[14/n] PR85694: Rework overwidening detection

Richard Sandiford richard.sandiford@arm.com
Wed Jun 20 10:37:00 GMT 2018


This patch is the main part of PR85694.  The aim is to recognise at least:

  signed char *a, *b, *c;
  ...
  for (int i = 0; i < 2048; i++)
    c[i] = (a[i] + b[i]) >> 1;

as an over-widening pattern, since the addition and shift can be done
on shorts rather than ints.  However, it ended up being a lot more
general than that.

The current over-widening pattern detection is limited to a few simple
cases: logical ops with immediate second operands, and shifts by a
constant.  These cases are enough for common pixel-format conversion
and can be detected in a peephole way.

The loop above requires two generalisations of the current code: support
for addition as well as logical ops, and support for non-constant second
operands.  These are harder to detect in the same peephole way, so the
patch tries to take a more global approach.

The idea is to get information about the minimum operation width
in two ways:

(1) by using the range information attached to the SSA_NAMEs
    (effectively a forward walk, since the range info is
    context-independent).

(2) by back-propagating the number of output bits required by
    users of the result.

As explained in the comments, there's a balance to be struck between
narrowing an individual operation and fitting in with the surrounding
code.  The approach is pretty conservative: if we could narrow an
operation to N bits without changing its semantics, it's OK to do that if:

- no operations later in the chain require more than N bits; or

- all internally-defined inputs are extended from N bits or fewer,
  and at least one of them is single-use.

See the comments for the rationale.

I didn't bother adding STMT_VINFO_* wrappers for the new fields
since the code seemed more readable without.

Tested on aarch64-linux-gnu and x86_64-linux-gnu.  OK to install?

Richard


2018-06-20  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* poly-int.h (print_hex): New function.
	* dumpfile.h (dump_dec, dump_hex): Declare.
	* dumpfile.c (dump_dec, dump_hex): New poly_wide_int functions.
	* tree-vectorizer.h (_stmt_vec_info): Add min_output_precision,
	min_input_precision, operation_precision and operation_sign.
	* tree-vect-patterns.c (vect_get_range_info): New function.
	(vect_same_loop_or_bb_p, vect_single_imm_use)
	(vect_operation_fits_smaller_type): Delete.
	(vect_look_through_possible_promotion): Add an optional
	single_use_p parameter.
	(vect_recog_over_widening_pattern): Rewrite to use new
	stmt_vec_info infomration.  Handle one operation at a time.
	(vect_recog_cast_forwprop_pattern, vect_narrowable_type_p)
	(vect_truncatable_operation_p, vect_set_operation_type)
	(vect_set_min_input_precision): New functions.
	(vect_determine_min_output_precision_1): Likewise.
	(vect_determine_min_output_precision): Likewise.
	(vect_determine_precisions_from_range): Likewise.
	(vect_determine_precisions_from_users): Likewise.
	(vect_determine_stmt_precisions, vect_determine_precisions): Likewise.
	(vect_vect_recog_func_ptrs): Put over_widening first.
	Add cast_forwprop.
	(vect_pattern_recog): Call vect_determine_precisions.

gcc/testsuite/
	* gcc.dg/vect/vect-over-widen-1.c: Update the scan tests for new
	over-widening messages.
	* gcc.dg/vect/vect-over-widen-1-big-array.c: Likewise.
	* gcc.dg/vect/vect-over-widen-2.c: Likewise.
	* gcc.dg/vect/vect-over-widen-2-big-array.c: Likewise.
	* gcc.dg/vect/vect-over-widen-3.c: Likewise.
	* gcc.dg/vect/vect-over-widen-3-big-array.c: Likewise.
	* gcc.dg/vect/vect-over-widen-4.c: Likewise.
	* gcc.dg/vect/vect-over-widen-4-big-array.c: Likewise.
	* gcc.dg/vect/bb-slp-over-widen-1.c: New test.
	* gcc.dg/vect/bb-slp-over-widen-2.c: Likewise.
	* gcc.dg/vect/vect-over-widen-5.c: Likewise.
	* gcc.dg/vect/vect-over-widen-6.c: Likewise.
	* gcc.dg/vect/vect-over-widen-7.c: Likewise.
	* gcc.dg/vect/vect-over-widen-8.c: Likewise.
	* gcc.dg/vect/vect-over-widen-9.c: Likewise.
	* gcc.dg/vect/vect-over-widen-10.c: Likewise.
	* gcc.dg/vect/vect-over-widen-11.c: Likewise.
	* gcc.dg/vect/vect-over-widen-12.c: Likewise.
	* gcc.dg/vect/vect-over-widen-13.c: Likewise.
	* gcc.dg/vect/vect-over-widen-14.c: Likewise.
	* gcc.dg/vect/vect-over-widen-15.c: Likewise.
	* gcc.dg/vect/vect-over-widen-16.c: Likewise.
	* gcc.dg/vect/vect-over-widen-17.c: Likewise.
	* gcc.dg/vect/vect-over-widen-18.c: Likewise.
	* gcc.dg/vect/vect-over-widen-19.c: Likewise.
	* gcc.dg/vect/vect-over-widen-20.c: Likewise.
	* gcc.dg/vect/vect-over-widen-21.c: Likewise.

Index: gcc/poly-int.h
===================================================================
*** gcc/poly-int.h	2018-06-20 11:36:19.000000000 +0100
--- gcc/poly-int.h	2018-06-20 11:36:20.135890693 +0100
*************** print_dec (const poly_int_pod<N, C> &val
*** 2420,2425 ****
--- 2420,2444 ----
  	     poly_coeff_traits<C>::signedness ? SIGNED : UNSIGNED);
  }
  
+ /* Use print_hex to print VALUE to FILE.  */
+ 
+ template<unsigned int N, typename C>
+ void
+ print_hex (const poly_int_pod<N, C> &value, FILE *file)
+ {
+   if (value.is_constant ())
+     print_hex (value.coeffs[0], file);
+   else
+     {
+       fprintf (file, "[");
+       for (unsigned int i = 0; i < N; ++i)
+ 	{
+ 	  print_hex (value.coeffs[i], file);
+ 	  fputc (i == N - 1 ? ']' : ',', file);
+ 	}
+     }
+ }
+ 
  /* Helper for calculating the distance between two points P1 and P2,
     in cases where known_le (P1, P2).  T1 and T2 are the types of the
     two positions, in either order.  The coefficients of P2 - P1 have
Index: gcc/dumpfile.h
===================================================================
*** gcc/dumpfile.h	2018-06-20 11:36:19.000000000 +0100
--- gcc/dumpfile.h	2018-06-20 11:36:20.131890728 +0100
*************** extern bool enable_rtl_dump_file (void);
*** 288,293 ****
--- 288,295 ----
  
  template<unsigned int N, typename C>
  void dump_dec (dump_flags_t, const poly_int<N, C> &);
+ extern void dump_dec (dump_flags_t, const poly_wide_int &, signop);
+ extern void dump_hex (dump_flags_t, const poly_wide_int &);
  
  /* In tree-dump.c  */
  extern void dump_node (const_tree, dump_flags_t, FILE *);
Index: gcc/dumpfile.c
===================================================================
*** gcc/dumpfile.c	2018-06-20 11:36:19.000000000 +0100
--- gcc/dumpfile.c	2018-06-20 11:36:20.131890728 +0100
*************** template void dump_dec (dump_flags_t, co
*** 512,517 ****
--- 512,539 ----
  template void dump_dec (dump_flags_t, const poly_offset_int &);
  template void dump_dec (dump_flags_t, const poly_widest_int &);
  
+ void
+ dump_dec (dump_flags_t dump_kind, const poly_wide_int &value, signop sgn)
+ {
+   if (dump_file && (dump_kind & pflags))
+     print_dec (value, dump_file, sgn);
+ 
+   if (alt_dump_file && (dump_kind & alt_flags))
+     print_dec (value, alt_dump_file, sgn);
+ }
+ 
+ /* Output VALUE in hexadecimal to appropriate dump streams.  */
+ 
+ void
+ dump_hex (dump_flags_t dump_kind, const poly_wide_int &value)
+ {
+   if (dump_file && (dump_kind & pflags))
+     print_hex (value, dump_file);
+ 
+   if (alt_dump_file && (dump_kind & alt_flags))
+     print_hex (value, alt_dump_file);
+ }
+ 
  /* Start a dump for PHASE. Store user-supplied dump flags in
     *FLAG_PTR.  Return the number of streams opened.  Set globals
     DUMP_FILE, and ALT_DUMP_FILE to point to the opened streams, and
Index: gcc/tree-vectorizer.h
===================================================================
*** gcc/tree-vectorizer.h	2018-06-20 11:36:19.000000000 +0100
--- gcc/tree-vectorizer.h	2018-06-20 11:36:20.139890658 +0100
*************** typedef struct _stmt_vec_info {
*** 872,877 ****
--- 872,892 ----
  
    /* The number of scalar stmt references from active SLP instances.  */
    unsigned int num_slp_uses;
+ 
+   /* If nonzero, the lhs of the statement could be truncated to this
+      many bits without affecting any users of the result.  */
+   unsigned int min_output_precision;
+ 
+   /* If nonzero, all non-boolean input operands have the same precision,
+      and they could each be truncated to this many bits without changing
+      the result.  */
+   unsigned int min_input_precision;
+ 
+   /* If OPERATION_BITS is nonzero, the statement could be performed on
+      an integer with the sign and number of bits given by OPERATION_SIGN
+      and OPERATION_BITS without changing the result.  */
+   unsigned int operation_precision;
+   signop operation_sign;
  } *stmt_vec_info;
  
  /* Information about a gather/scatter call.  */
Index: gcc/tree-vect-patterns.c
===================================================================
*** gcc/tree-vect-patterns.c	2018-06-20 11:36:19.000000000 +0100
--- gcc/tree-vect-patterns.c	2018-06-20 11:36:20.139890658 +0100
*************** Software Foundation; either version 3, o
*** 47,52 ****
--- 47,86 ----
  #include "omp-simd-clone.h"
  #include "predict.h"
  
+ /* Return true if we have a useful VR_RANGE range for VAR, storing it
+    in *MIN_VALUE and *MAX_VALUE if so.  Note the range in the dump files.  */
+ 
+ static bool
+ vect_get_range_info (tree var, wide_int *min_value, wide_int *max_value)
+ {
+   value_range_type vr_type = get_range_info (var, min_value, max_value);
+   wide_int nonzero = get_nonzero_bits (var);
+   signop sgn = TYPE_SIGN (TREE_TYPE (var));
+   if (intersect_range_with_nonzero_bits (vr_type, min_value, max_value,
+ 					 nonzero, sgn) == VR_RANGE)
+     {
+       if (dump_enabled_p ())
+ 	{
+ 	  dump_generic_expr_loc (MSG_NOTE, vect_location, TDF_SLIM, var);
+ 	  dump_printf (MSG_NOTE, " has range [");
+ 	  dump_hex (MSG_NOTE, *min_value);
+ 	  dump_printf (MSG_NOTE, ", ");
+ 	  dump_hex (MSG_NOTE, *max_value);
+ 	  dump_printf (MSG_NOTE, "]\n");
+ 	}
+       return true;
+     }
+   else
+     {
+       if (dump_enabled_p ())
+ 	{
+ 	  dump_generic_expr_loc (MSG_NOTE, vect_location, TDF_SLIM, var);
+ 	  dump_printf (MSG_NOTE, " has no range info\n");
+ 	}
+       return false;
+     }
+ }
+ 
  /* Report that we've found an instance of pattern PATTERN in
     statement STMT.  */
  
*************** vect_supportable_direct_optab_p (tree ot
*** 190,229 ****
    return true;
  }
  
- /* Check whether STMT2 is in the same loop or basic block as STMT1.
-    Which of the two applies depends on whether we're currently doing
-    loop-based or basic-block-based vectorization, as determined by
-    the vinfo_for_stmt for STMT1 (which must be defined).
- 
-    If this returns true, vinfo_for_stmt for STMT2 is guaranteed
-    to be defined as well.  */
- 
- static bool
- vect_same_loop_or_bb_p (gimple *stmt1, gimple *stmt2)
- {
-   stmt_vec_info stmt_vinfo = vinfo_for_stmt (stmt1);
-   return vect_stmt_in_region_p (stmt_vinfo->vinfo, stmt2);
- }
- 
- /* If the LHS of DEF_STMT has a single use, and that statement is
-    in the same loop or basic block, return it.  */
- 
- static gimple *
- vect_single_imm_use (gimple *def_stmt)
- {
-   tree lhs = gimple_assign_lhs (def_stmt);
-   use_operand_p use_p;
-   gimple *use_stmt;
- 
-   if (!single_imm_use (lhs, &use_p, &use_stmt))
-     return NULL;
- 
-   if (!vect_same_loop_or_bb_p (def_stmt, use_stmt))
-     return NULL;
- 
-   return use_stmt;
- }
- 
  /* If OP is defined by a statement that's being considered for vectorization,
     return information about that statement, otherwise return NULL.  */
  
--- 224,229 ----
*************** vect_unpromoted_value::set_op (tree op_i
*** 341,347 ****
     is possible to convert OP' back to OP using a possible sign change
     followed by a possible promotion P.  Return this OP', or null if OP is
     not a vectorizable SSA name.  If there is a promotion P, describe its
!    input in UNPROM, otherwise describe OP' in UNPROM.
  
     A successful return means that it is possible to go from OP' to OP
     via UNPROM.  The cast from OP' to UNPROM is at most a sign change,
--- 341,349 ----
     is possible to convert OP' back to OP using a possible sign change
     followed by a possible promotion P.  Return this OP', or null if OP is
     not a vectorizable SSA name.  If there is a promotion P, describe its
!    input in UNPROM, otherwise describe OP' in UNPROM.  If SINGLE_USE_P
!    is nonnull, set *SINGLE_USE_P to false if any of the SSA names involved
!    have more than one user.
  
     A successful return means that it is possible to go from OP' to OP
     via UNPROM.  The cast from OP' to UNPROM is at most a sign change,
*************** vect_unpromoted_value::set_op (tree op_i
*** 368,374 ****
  
  static tree
  vect_look_through_possible_promotion (vec_info *vinfo, tree op,
! 				      vect_unpromoted_value *unprom)
  {
    tree res = NULL_TREE;
    tree op_type = TREE_TYPE (op);
--- 370,377 ----
  
  static tree
  vect_look_through_possible_promotion (vec_info *vinfo, tree op,
! 				      vect_unpromoted_value *unprom,
! 				      bool *single_use_p = NULL)
  {
    tree res = NULL_TREE;
    tree op_type = TREE_TYPE (op);
*************** vect_look_through_possible_promotion (ve
*** 417,422 ****
--- 420,430 ----
  	{
  	  def_stmt = vect_look_through_pattern (def_stmt);
  	  caster = vinfo_for_stmt (def_stmt);
+ 	  /* Ignore pattern statements, since we don't link uses for them.  */
+ 	  if (single_use_p
+ 	      && !STMT_VINFO_RELATED_STMT (caster)
+ 	      && !has_single_use (res))
+ 	    *single_use_p = false;
  	}
        else
  	caster = NULL;
*************** vect_recog_widen_sum_pattern (vec<gimple
*** 1307,1669 ****
    return pattern_stmt;
  }
  
  
! /* Return TRUE if the operation in STMT can be performed on a smaller type.
! 
!    Input:
!    STMT - a statement to check.
!    DEF - we support operations with two operands, one of which is constant.
!          The other operand can be defined by a demotion operation, or by a
!          previous statement in a sequence of over-promoted operations.  In the
!          later case DEF is used to replace that operand.  (It is defined by a
!          pattern statement we created for the previous statement in the
!          sequence).
! 
!    Input/output:
!    NEW_TYPE - Output: a smaller type that we are trying to use.  Input: if not
!          NULL, it's the type of DEF.
!    STMTS - additional pattern statements.  If a pattern statement (type
!          conversion) is created in this function, its original statement is
!          added to STMTS.
  
!    Output:
!    OP0, OP1 - if the operation fits a smaller type, OP0 and OP1 are the new
!          operands to use in the new pattern statement for STMT (will be created
!          in vect_recog_over_widening_pattern ()).
!    NEW_DEF_STMT - in case DEF has to be promoted, we create two pattern
!          statements for STMT: the first one is a type promotion and the second
!          one is the operation itself.  We return the type promotion statement
! 	 in NEW_DEF_STMT and further store it in STMT_VINFO_PATTERN_DEF_SEQ of
!          the second pattern statement.  */
  
! static bool
! vect_operation_fits_smaller_type (gimple *stmt, tree def, tree *new_type,
! 				  tree *op0, tree *op1, gimple **new_def_stmt,
! 				  vec<gimple *> *stmts)
! {
!   enum tree_code code;
!   tree const_oprnd, oprnd;
!   tree interm_type = NULL_TREE, half_type, new_oprnd, type;
!   gimple *def_stmt, *new_stmt;
!   bool first = false;
!   bool promotion;
  
!   *op0 = NULL_TREE;
!   *op1 = NULL_TREE;
!   *new_def_stmt = NULL;
  
!   if (!is_gimple_assign (stmt))
!     return false;
  
!   code = gimple_assign_rhs_code (stmt);
!   if (code != LSHIFT_EXPR && code != RSHIFT_EXPR
!       && code != BIT_IOR_EXPR && code != BIT_XOR_EXPR && code != BIT_AND_EXPR)
!     return false;
  
!   oprnd = gimple_assign_rhs1 (stmt);
!   const_oprnd = gimple_assign_rhs2 (stmt);
!   type = gimple_expr_type (stmt);
  
!   if (TREE_CODE (oprnd) != SSA_NAME
!       || TREE_CODE (const_oprnd) != INTEGER_CST)
!     return false;
  
!   /* If oprnd has other uses besides that in stmt we cannot mark it
!      as being part of a pattern only.  */
!   if (!has_single_use (oprnd))
!     return false;
  
!   /* If we are in the middle of a sequence, we use DEF from a previous
!      statement.  Otherwise, OPRND has to be a result of type promotion.  */
!   if (*new_type)
!     {
!       half_type = *new_type;
!       oprnd = def;
!     }
!   else
      {
!       first = true;
!       if (!type_conversion_p (oprnd, stmt, false, &half_type, &def_stmt,
! 			      &promotion)
! 	  || !promotion
! 	  || !vect_same_loop_or_bb_p (stmt, def_stmt))
!         return false;
      }
  
!   /* Can we perform the operation on a smaller type?  */
!   switch (code)
!     {
!       case BIT_IOR_EXPR:
!       case BIT_XOR_EXPR:
!       case BIT_AND_EXPR:
!         if (!int_fits_type_p (const_oprnd, half_type))
!           {
!             /* HALF_TYPE is not enough.  Try a bigger type if possible.  */
!             if (TYPE_PRECISION (type) < (TYPE_PRECISION (half_type) * 4))
!               return false;
! 
!             interm_type = build_nonstandard_integer_type (
!                         TYPE_PRECISION (half_type) * 2, TYPE_UNSIGNED (type));
!             if (!int_fits_type_p (const_oprnd, interm_type))
!               return false;
!           }
! 
!         break;
! 
!       case LSHIFT_EXPR:
!         /* Try intermediate type - HALF_TYPE is not enough for sure.  */
!         if (TYPE_PRECISION (type) < (TYPE_PRECISION (half_type) * 4))
!           return false;
! 
!         /* Check that HALF_TYPE size + shift amount <= INTERM_TYPE size.
!           (e.g., if the original value was char, the shift amount is at most 8
!            if we want to use short).  */
!         if (compare_tree_int (const_oprnd, TYPE_PRECISION (half_type)) == 1)
!           return false;
! 
!         interm_type = build_nonstandard_integer_type (
!                         TYPE_PRECISION (half_type) * 2, TYPE_UNSIGNED (type));
! 
!         if (!vect_supportable_shift (code, interm_type))
!           return false;
! 
!         break;
! 
!       case RSHIFT_EXPR:
!         if (vect_supportable_shift (code, half_type))
!           break;
! 
!         /* Try intermediate type - HALF_TYPE is not supported.  */
!         if (TYPE_PRECISION (type) < (TYPE_PRECISION (half_type) * 4))
!           return false;
! 
!         interm_type = build_nonstandard_integer_type (
!                         TYPE_PRECISION (half_type) * 2, TYPE_UNSIGNED (type));
! 
!         if (!vect_supportable_shift (code, interm_type))
!           return false;
! 
!         break;
! 
!       default:
!         gcc_unreachable ();
!     }
! 
!   /* There are four possible cases:
!      1. OPRND is defined by a type promotion (in that case FIRST is TRUE, it's
!         the first statement in the sequence)
!         a. The original, HALF_TYPE, is not enough - we replace the promotion
!            from HALF_TYPE to TYPE with a promotion to INTERM_TYPE.
!         b. HALF_TYPE is sufficient, OPRND is set as the RHS of the original
!            promotion.
!      2. OPRND is defined by a pattern statement we created.
!         a. Its type is not sufficient for the operation, we create a new stmt:
!            a type conversion for OPRND from HALF_TYPE to INTERM_TYPE.  We store
!            this statement in NEW_DEF_STMT, and it is later put in
! 	   STMT_VINFO_PATTERN_DEF_SEQ of the pattern statement for STMT.
!         b. OPRND is good to use in the new statement.  */
!   if (first)
!     {
!       if (interm_type)
!         {
!           /* Replace the original type conversion HALF_TYPE->TYPE with
!              HALF_TYPE->INTERM_TYPE.  */
!           if (STMT_VINFO_RELATED_STMT (vinfo_for_stmt (def_stmt)))
!             {
!               new_stmt = STMT_VINFO_RELATED_STMT (vinfo_for_stmt (def_stmt));
!               /* Check if the already created pattern stmt is what we need.  */
!               if (!is_gimple_assign (new_stmt)
!                   || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (new_stmt))
!                   || TREE_TYPE (gimple_assign_lhs (new_stmt)) != interm_type)
!                 return false;
! 
! 	      stmts->safe_push (def_stmt);
!               oprnd = gimple_assign_lhs (new_stmt);
!             }
!           else
!             {
!               /* Create NEW_OPRND = (INTERM_TYPE) OPRND.  */
!               oprnd = gimple_assign_rhs1 (def_stmt);
! 	      new_oprnd = make_ssa_name (interm_type);
! 	      new_stmt = gimple_build_assign (new_oprnd, NOP_EXPR, oprnd);
!               STMT_VINFO_RELATED_STMT (vinfo_for_stmt (def_stmt)) = new_stmt;
!               stmts->safe_push (def_stmt);
!               oprnd = new_oprnd;
!             }
!         }
!       else
!         {
!           /* Retrieve the operand before the type promotion.  */
!           oprnd = gimple_assign_rhs1 (def_stmt);
!         }
!     }
!   else
!     {
!       if (interm_type)
!         {
!           /* Create a type conversion HALF_TYPE->INTERM_TYPE.  */
! 	  new_oprnd = make_ssa_name (interm_type);
! 	  new_stmt = gimple_build_assign (new_oprnd, NOP_EXPR, oprnd);
!           oprnd = new_oprnd;
!           *new_def_stmt = new_stmt;
!         }
  
!       /* Otherwise, OPRND is already set.  */
      }
  
!   if (interm_type)
!     *new_type = interm_type;
!   else
!     *new_type = half_type;
! 
!   *op0 = oprnd;
!   *op1 = fold_convert (*new_type, const_oprnd);
  
!   return true;
  }
  
  
! /* Try to find a statement or a sequence of statements that can be performed
!    on a smaller type:
  
!      type x_t;
!      TYPE x_T, res0_T, res1_T;
!    loop:
!      S1  x_t = *p;
!      S2  x_T = (TYPE) x_t;
!      S3  res0_T = op (x_T, C0);
!      S4  res1_T = op (res0_T, C1);
!      S5  ... = () res1_T;  - type demotion
! 
!    where type 'TYPE' is at least double the size of type 'type', C0 and C1 are
!    constants.
!    Check if S3 and S4 can be done on a smaller type than 'TYPE', it can either
!    be 'type' or some intermediate type.  For now, we expect S5 to be a type
!    demotion operation.  We also check that S3 and S4 have only one use.  */
  
! static gimple *
! vect_recog_over_widening_pattern (vec<gimple *> *stmts, tree *type_out)
! {
!   gimple *stmt = stmts->pop ();
!   gimple *pattern_stmt = NULL, *new_def_stmt, *prev_stmt = NULL,
! 	 *use_stmt = NULL;
!   tree op0, op1, vectype = NULL_TREE, use_lhs, use_type;
!   tree var = NULL_TREE, new_type = NULL_TREE, new_oprnd;
!   bool first;
!   tree type = NULL;
! 
!   first = true;
!   while (1)
!     {
!       if (!vinfo_for_stmt (stmt)
!           || STMT_VINFO_IN_PATTERN_P (vinfo_for_stmt (stmt)))
!         return NULL;
! 
!       new_def_stmt = NULL;
!       if (!vect_operation_fits_smaller_type (stmt, var, &new_type,
!                                              &op0, &op1, &new_def_stmt,
!                                              stmts))
!         {
!           if (first)
!             return NULL;
!           else
!             break;
!         }
  
!       /* STMT can be performed on a smaller type.  Check its uses.  */
!       use_stmt = vect_single_imm_use (stmt);
!       if (!use_stmt || !is_gimple_assign (use_stmt))
!         return NULL;
! 
!       /* Create pattern statement for STMT.  */
!       vectype = get_vectype_for_scalar_type (new_type);
!       if (!vectype)
!         return NULL;
! 
!       /* We want to collect all the statements for which we create pattern
!          statetments, except for the case when the last statement in the
!          sequence doesn't have a corresponding pattern statement.  In such
!          case we associate the last pattern statement with the last statement
!          in the sequence.  Therefore, we only add the original statement to
!          the list if we know that it is not the last.  */
!       if (prev_stmt)
!         stmts->safe_push (prev_stmt);
  
!       var = vect_recog_temp_ssa_var (new_type, NULL);
!       pattern_stmt
! 	= gimple_build_assign (var, gimple_assign_rhs_code (stmt), op0, op1);
!       STMT_VINFO_RELATED_STMT (vinfo_for_stmt (stmt)) = pattern_stmt;
!       new_pattern_def_seq (vinfo_for_stmt (stmt), new_def_stmt);
  
!       if (dump_enabled_p ())
!         {
!           dump_printf_loc (MSG_NOTE, vect_location,
!                            "created pattern stmt: ");
!           dump_gimple_stmt (MSG_NOTE, TDF_SLIM, pattern_stmt, 0);
!         }
  
!       type = gimple_expr_type (stmt);
!       prev_stmt = stmt;
!       stmt = use_stmt;
! 
!       first = false;
!     }
! 
!   /* We got a sequence.  We expect it to end with a type demotion operation.
!      Otherwise, we quit (for now).  There are three possible cases: the
!      conversion is to NEW_TYPE (we don't do anything), the conversion is to
!      a type bigger than NEW_TYPE and/or the signedness of USE_TYPE and
!      NEW_TYPE differs (we create a new conversion statement).  */
!   if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (use_stmt)))
!     {
!       use_lhs = gimple_assign_lhs (use_stmt);
!       use_type = TREE_TYPE (use_lhs);
!       /* Support only type demotion or signedess change.  */
!       if (!INTEGRAL_TYPE_P (use_type)
! 	  || TYPE_PRECISION (type) <= TYPE_PRECISION (use_type))
!         return NULL;
  
!       /* Check that NEW_TYPE is not bigger than the conversion result.  */
!       if (TYPE_PRECISION (new_type) > TYPE_PRECISION (use_type))
! 	return NULL;
  
!       if (TYPE_UNSIGNED (new_type) != TYPE_UNSIGNED (use_type)
!           || TYPE_PRECISION (new_type) != TYPE_PRECISION (use_type))
!         {
! 	  *type_out = get_vectype_for_scalar_type (use_type);
! 	  if (!*type_out)
! 	    return NULL;
  
!           /* Create NEW_TYPE->USE_TYPE conversion.  */
! 	  new_oprnd = make_ssa_name (use_type);
! 	  pattern_stmt = gimple_build_assign (new_oprnd, NOP_EXPR, var);
!           STMT_VINFO_RELATED_STMT (vinfo_for_stmt (use_stmt)) = pattern_stmt;
! 
!           /* We created a pattern statement for the last statement in the
!              sequence, so we don't need to associate it with the pattern
!              statement created for PREV_STMT.  Therefore, we add PREV_STMT
!              to the list in order to mark it later in vect_pattern_recog_1.  */
!           if (prev_stmt)
!             stmts->safe_push (prev_stmt);
!         }
!       else
!         {
!           if (prev_stmt)
! 	    STMT_VINFO_PATTERN_DEF_SEQ (vinfo_for_stmt (use_stmt))
! 	       = STMT_VINFO_PATTERN_DEF_SEQ (vinfo_for_stmt (prev_stmt));
  
! 	  *type_out = vectype;
!         }
  
!       stmts->safe_push (use_stmt);
!     }
!   else
!     /* TODO: support general case, create a conversion to the correct type.  */
      return NULL;
  
!   /* Pattern detected.  */
!   vect_pattern_detected ("vect_recog_over_widening_pattern", stmts->last ());
  
    return pattern_stmt;
  }
  
--- 1315,1632 ----
    return pattern_stmt;
  }
  
+ /* Recognize cases in which an operation is performed in one type WTYPE
+    but could be done more efficiently in a narrower type NTYPE.  For example,
+    if we have:
+ 
+      ATYPE a;  // narrower than NTYPE
+      BTYPE b;  // narrower than NTYPE
+      WTYPE aw = (WTYPE) a;
+      WTYPE bw = (WTYPE) b;
+      WTYPE res = aw + bw;  // only uses of aw and bw
+ 
+    then it would be more efficient to do:
+ 
+      NTYPE an = (NTYPE) a;
+      NTYPE bn = (NTYPE) b;
+      NTYPE resn = an + bn;
+      WTYPE res = (WTYPE) resn;
+ 
+    Other situations include things like:
+ 
+      ATYPE a;  // NTYPE or narrower
+      WTYPE aw = (WTYPE) a;
+      WTYPE res = aw + b;
+ 
+    when only "(NTYPE) res" is significant.  In that case it's more efficient
+    to truncate "b" and do the operation on NTYPE instead:
+ 
+      NTYPE an = (NTYPE) a;
+      NTYPE bn = (NTYPE) b;  // truncation
+      NTYPE resn = an + bn;
+      WTYPE res = (WTYPE) resn;
+ 
+    All users of "res" should then use "resn" instead, making the final
+    statement dead (not marked as relevant).  The final statement is still
+    needed to maintain the type correctness of the IR.
+ 
+    vect_determine_precisions has already determined the minimum
+    precison of the operation and the minimum precision required
+    by users of the result.  */
  
! static gimple *
! vect_recog_over_widening_pattern (vec<gimple *> *stmts, tree *type_out)
! {
!   gassign *last_stmt = dyn_cast <gassign *> (stmts->pop ());
!   if (!last_stmt)
!     return NULL;
  
!   /* See whether we have found that this operation can be done on a
!      narrower type without changing its semantics.  */
!   stmt_vec_info last_stmt_info = vinfo_for_stmt (last_stmt);
!   unsigned int new_precision = last_stmt_info->operation_precision;
!   if (!new_precision)
!     return NULL;
  
!   vec_info *vinfo = last_stmt_info->vinfo;
!   tree lhs = gimple_assign_lhs (last_stmt);
!   tree type = TREE_TYPE (lhs);
!   tree_code code = gimple_assign_rhs_code (last_stmt);
! 
!   /* Keep the first operand of a COND_EXPR as-is: only the other two
!      operands are interesting.  */
!   unsigned int first_op = (code == COND_EXPR ? 2 : 1);
! 
!   /* Check the operands.  */
!   unsigned int nops = gimple_num_ops (last_stmt) - first_op;
!   auto_vec <vect_unpromoted_value, 3> unprom (nops);
!   unprom.quick_grow (nops);
!   unsigned int min_precision = 0;
!   bool single_use_p = false;
!   for (unsigned int i = 0; i < nops; ++i)
!     {
!       tree op = gimple_op (last_stmt, first_op + i);
!       if (TREE_CODE (op) == INTEGER_CST)
! 	unprom[i].set_op (op, vect_constant_def);
!       else if (TREE_CODE (op) == SSA_NAME)
! 	{
! 	  bool op_single_use_p = true;
! 	  if (!vect_look_through_possible_promotion (vinfo, op, &unprom[i],
! 						     &op_single_use_p))
! 	    return NULL;
! 	  /* If:
  
! 	     (1) N bits of the result are needed;
! 	     (2) all inputs are widened from M<N bits; and
! 	     (3) one operand OP is a single-use SSA name
! 
! 	     we can shift the M->N widening from OP to the output
! 	     without changing the number or type of extensions involved.
! 	     This then reduces the number of copies of STMT_INFO.
! 
! 	     If instead of (3) more than one operand is a single-use SSA name,
! 	     shifting the extension to the output is even more of a win.
! 
! 	     If instead:
! 
! 	     (1) N bits of the result are needed;
! 	     (2) one operand OP2 is widened from M2<N bits;
! 	     (3) another operand OP1 is widened from M1<M2 bits; and
! 	     (4) both OP1 and OP2 are single-use
! 
! 	     the choice is between:
! 
! 	     (a) truncating OP2 to M1, doing the operation on M1,
! 		 and then widening the result to N
! 
! 	     (b) widening OP1 to M2, doing the operation on M2, and then
! 		 widening the result to N
! 
! 	     Both shift the M2->N widening of the inputs to the output.
! 	     (a) additionally shifts the M1->M2 widening to the output;
! 	     it requires fewer copies of STMT_INFO but requires an extra
! 	     M2->M1 truncation.
! 
! 	     Which is better will depend on the complexity and cost of
! 	     STMT_INFO, which is hard to predict at this stage.  However,
! 	     a clear tie-breaker in favor of (b) is the fact that the
! 	     truncation in (a) increases the length of the operation chain.
! 
! 	     If instead of (4) only one of OP1 or OP2 is single-use,
! 	     (b) is still a win over doing the operation in N bits:
! 	     it still shifts the M2->N widening on the single-use operand
! 	     to the output and reduces the number of STMT_INFO copies.
! 
! 	     If neither operand is single-use then operating on fewer than
! 	     N bits might lead to more extensions overall.  Whether it does
! 	     or not depends on global information about the vectorization
! 	     region, and whether that's a good trade-off would again
! 	     depend on the complexity and cost of the statements involved,
! 	     as well as things like register pressure that are not normally
! 	     modelled at this stage.  We therefore ignore these cases
! 	     and just optimize the clear single-use wins above.
! 
! 	     Thus we take the maximum precision of the unpromoted operands
! 	     and record whether any operand is single-use.  */
! 	  if (unprom[i].dt == vect_internal_def)
! 	    {
! 	      min_precision = MAX (min_precision,
! 				   TYPE_PRECISION (unprom[i].type));
! 	      single_use_p |= op_single_use_p;
! 	    }
! 	}
!     }
  
!   /* Although the operation could be done in operation_precision, we have
!      to balance that against introducing extra truncations or extensions.
!      Calculate the minimum precision that can be handled efficiently.
! 
!      The loop above determined that the operation could be handled
!      efficiently in MIN_PRECISION if SINGLE_USE_P; this would shift an
!      extension from the inputs to the output without introducing more
!      instructions, and would reduce the number of instructions required
!      for STMT_INFO itself.
! 
!      vect_determine_precisions has also determined that the result only
!      needs min_output_precision bits.  Truncating by a factor of N times
!      requires a tree of N - 1 instructions, so if TYPE is N times wider
!      than min_output_precision, doing the operation in TYPE and truncating
!      the result requires N + (N - 1) = 2N - 1 instructions per output vector.
!      In contrast:
! 
!      - truncating the input to a unary operation and doing the operation
!        in the new type requires at most N - 1 + 1 = N instructions per
!        output vector
! 
!      - doing the same for a binary operation requires at most
!        (N - 1) * 2 + 1 = 2N - 1 instructions per output vector
! 
!      Both unary and binary operations require fewer instructions than
!      this if the operands were extended from a suitable truncated form.
!      Thus there is usually nothing to lose by doing operations in
!      min_output_precision bits, but there can be something to gain.  */
!   if (!single_use_p)
!     min_precision = last_stmt_info->min_output_precision;
!   else
!     min_precision = MIN (min_precision, last_stmt_info->min_output_precision);
  
!   /* Apply the minimum efficient precision we just calculated.  */
!   if (new_precision < min_precision)
!     new_precision = min_precision;
!   if (new_precision >= TYPE_PRECISION (type))
!     return NULL;
  
!   vect_pattern_detected ("vect_recog_over_widening_pattern", last_stmt);
  
!   *type_out = get_vectype_for_scalar_type (type);
!   if (!*type_out)
!     return NULL;
  
!   /* We've found a viable pattern.  Get the new type of the operation.  */
!   bool unsigned_p = (last_stmt_info->operation_sign == UNSIGNED);
!   tree new_type = build_nonstandard_integer_type (new_precision, unsigned_p);
! 
!   /* We specifically don't check here whether the target supports the
!      new operation, since it might be something that a later pattern
!      wants to rewrite anyway.  If targets have a minimum element size
!      for some optabs, we should pattern-match smaller ops to larger ops
!      where beneficial.  */
!   tree new_vectype = get_vectype_for_scalar_type (new_type);
!   if (!new_vectype)
!     return NULL;
  
!   if (dump_enabled_p ())
      {
!       dump_printf_loc (MSG_NOTE, vect_location, "demoting ");
!       dump_generic_expr (MSG_NOTE, TDF_SLIM, type);
!       dump_printf (MSG_NOTE, " to ");
!       dump_generic_expr (MSG_NOTE, TDF_SLIM, new_type);
!       dump_printf (MSG_NOTE, "\n");
      }
  
!   /* Calculate the rhs operands for an operation on NEW_TYPE.  */
!   STMT_VINFO_PATTERN_DEF_SEQ (last_stmt_info) = NULL;
!   tree ops[3] = {};
!   for (unsigned int i = 1; i < first_op; ++i)
!     ops[i - 1] = gimple_op (last_stmt, i);
!   vect_convert_inputs (last_stmt_info, nops, &ops[first_op - 1],
! 		       new_type, &unprom[0], new_vectype);
! 
!   /* Use the operation to produce a result of type NEW_TYPE.  */
!   tree new_var = vect_recog_temp_ssa_var (new_type, NULL);
!   gimple *pattern_stmt = gimple_build_assign (new_var, code,
! 					      ops[0], ops[1], ops[2]);
!   gimple_set_location (pattern_stmt, gimple_location (last_stmt));
  
!   if (dump_enabled_p ())
!     {
!       dump_printf_loc (MSG_NOTE, vect_location,
! 		       "created pattern stmt: ");
!       dump_gimple_stmt (MSG_NOTE, TDF_SLIM, pattern_stmt, 0);
      }
  
!   pattern_stmt = vect_convert_output (last_stmt_info, type,
! 				      pattern_stmt, new_vectype);
  
!   stmts->safe_push (last_stmt);
!   return pattern_stmt;
  }
  
+ /* Recognize cases in which the input to a cast is wider than its
+    output, and the input is fed by a widening operation.  Fold this
+    by removing the unnecessary intermediate widening.  E.g.:
  
!      unsigned char a;
!      unsigned int b = (unsigned int) a;
!      unsigned short c = (unsigned short) b;
  
!    -->
  
!      unsigned short c = (unsigned short) a;
  
!    Although this is rare in input IR, it is an expected side-effect
!    of the over-widening pattern above.
  
!    This is beneficial also for integer-to-float conversions, if the
!    widened integer has more bits than the float, and if the unwidened
!    input doesn't.  */
  
! static gimple *
! vect_recog_cast_forwprop_pattern (vec<gimple *> *stmts, tree *type_out)
! {
!   /* Check for a cast, including an integer-to-float conversion.  */
!   gassign *last_stmt = dyn_cast <gassign *> (stmts->pop ());
!   if (!last_stmt)
!     return NULL;
!   tree_code code = gimple_assign_rhs_code (last_stmt);
!   if (!CONVERT_EXPR_CODE_P (code) && code != FLOAT_EXPR)
!     return NULL;
  
!   /* Make sure that the rhs is a scalar with a natural bitsize.  */
!   tree lhs = gimple_assign_lhs (last_stmt);
!   if (!lhs)
!     return NULL;
!   tree lhs_type = TREE_TYPE (lhs);
!   scalar_mode lhs_mode;
!   if (VECT_SCALAR_BOOLEAN_TYPE_P (lhs_type)
!       || !is_a <scalar_mode> (TYPE_MODE (lhs_type), &lhs_mode))
!     return NULL;
  
!   /* Check for a narrowing operation (from a vector point of view).  */
!   tree rhs = gimple_assign_rhs1 (last_stmt);
!   tree rhs_type = TREE_TYPE (rhs);
!   if (!INTEGRAL_TYPE_P (rhs_type)
!       || VECT_SCALAR_BOOLEAN_TYPE_P (rhs_type)
!       || TYPE_PRECISION (rhs_type) <= GET_MODE_BITSIZE (lhs_mode))
!     return NULL;
  
!   /* Try to find an unpromoted input.  */
!   stmt_vec_info last_stmt_info = vinfo_for_stmt (last_stmt);
!   vec_info *vinfo = last_stmt_info->vinfo;
!   vect_unpromoted_value unprom;
!   if (!vect_look_through_possible_promotion (vinfo, rhs, &unprom)
!       || TYPE_PRECISION (unprom.type) >= TYPE_PRECISION (rhs_type))
!     return NULL;
  
!   /* If the bits above RHS_TYPE matter, make sure that they're the
!      same when extending from UNPROM as they are when extending from RHS.  */
!   if (!INTEGRAL_TYPE_P (lhs_type)
!       && TYPE_SIGN (rhs_type) != TYPE_SIGN (unprom.type))
!     return NULL;
  
!   /* We can get the same result by casting UNPROM directly, to avoid
!      the unnecessary widening and narrowing.  */
!   vect_pattern_detected ("vect_recog_cast_forwprop_pattern", last_stmt);
  
!   *type_out = get_vectype_for_scalar_type (lhs_type);
!   if (!*type_out)
      return NULL;
  
!   tree new_var = vect_recog_temp_ssa_var (lhs_type, NULL);
!   gimple *pattern_stmt = gimple_build_assign (new_var, NOP_EXPR, unprom.op);
!   gimple_set_location (pattern_stmt, gimple_location (last_stmt));
  
+   stmts->safe_push (last_stmt);
    return pattern_stmt;
  }
  
*************** vect_recog_gather_scatter_pattern (vec<g
*** 4145,4150 ****
--- 4108,4498 ----
    return pattern_stmt;
  }
  
+ /* Return true if TYPE is a non-boolean integer type.  These are the types
+    that we want to consider for narrowing.  */
+ 
+ static bool
+ vect_narrowable_type_p (tree type)
+ {
+   return INTEGRAL_TYPE_P (type) && !VECT_SCALAR_BOOLEAN_TYPE_P (type);
+ }
+ 
+ /* Return true if the operation given by CODE can be truncated to N bits
+    when only N bits of the output are needed.  This is only true if bit N+1
+    of the inputs has no effect on the low N bits of the result.  */
+ 
+ static bool
+ vect_truncatable_operation_p (tree_code code)
+ {
+   switch (code)
+     {
+     case PLUS_EXPR:
+     case MINUS_EXPR:
+     case MULT_EXPR:
+     case BIT_AND_EXPR:
+     case BIT_IOR_EXPR:
+     case BIT_XOR_EXPR:
+     case COND_EXPR:
+       return true;
+ 
+     default:
+       return false;
+     }
+ }
+ 
+ /* Record that STMT_INFO could be changed from operating on TYPE to
+    operating on a type with the precision and sign given by PRECISION
+    and SIGN respectively.  PRECISION is an arbitrary bit precision;
+    it might not be a whole number of bytes.  */
+ 
+ static void
+ vect_set_operation_type (stmt_vec_info stmt_info, tree type,
+ 			 unsigned int precision, signop sign)
+ {
+   /* Round the precision up to a whole number of bytes.  */
+   precision = 1 << ceil_log2 (precision);
+   precision = MAX (precision, BITS_PER_UNIT);
+   if (precision < TYPE_PRECISION (type)
+       && (!stmt_info->operation_precision
+ 	  || stmt_info->operation_precision > precision))
+     {
+       stmt_info->operation_precision = precision;
+       stmt_info->operation_sign = sign;
+     }
+ }
+ 
+ /* Record that STMT_INFO only requires MIN_INPUT_PRECISION from its
+    non-boolean inputs, all of which have type TYPE.  MIN_INPUT_PRECISION
+    is an arbitrary bit precision; it might not be a whole number of bytes.  */
+ 
+ static void
+ vect_set_min_input_precision (stmt_vec_info stmt_info, tree type,
+ 			      unsigned int min_input_precision)
+ {
+   /* This operation in isolation only requires the inputs to have
+      MIN_INPUT_PRECISION of precision,  However, that doesn't mean
+      that MIN_INPUT_PRECISION is a natural precision for the chain
+      as a whole.  E.g. consider something like:
+ 
+ 	 unsigned short *x, *y;
+ 	 *y = ((*x & 0xf0) >> 4) | (*y << 4);
+ 
+      The right shift can be done on unsigned chars, and only requires the
+      result of "*x & 0xf0" to be done on unsigned chars.  But taking that
+      approach would mean turning a natural chain of single-vector unsigned
+      short operations into one that truncates "*x" and then extends
+      "(*x & 0xf0) >> 4", with two vectors for each unsigned short
+      operation and one vector for each unsigned char operation.
+      This would be a significant pessimization.
+ 
+      Instead only propagate the maximum of this precision and the precision
+      required by the users of the result.  This means that we don't pessimize
+      the case above but continue to optimize things like:
+ 
+ 	 unsigned char *y;
+ 	 unsigned short *x;
+ 	 *y = ((*x & 0xf0) >> 4) | (*y << 4);
+ 
+      Here we would truncate two vectors of *x to a single vector of
+      unsigned chars and use single-vector unsigned char operations for
+      everything else, rather than doing two unsigned short copies of
+      "(*x & 0xf0) >> 4" and then truncating the result.  */
+   min_input_precision = MAX (min_input_precision,
+ 			     stmt_info->min_output_precision);
+ 
+   if (min_input_precision < TYPE_PRECISION (type)
+       && (!stmt_info->min_input_precision
+ 	  || stmt_info->min_input_precision > min_input_precision))
+     stmt_info->min_input_precision = min_input_precision;
+ }
+ 
+ /* Subroutine of vect_determine_min_output_precision.  Return true if
+    we can calculate a reduced number of output bits for STMT_INFO,
+    whose result is LHS.  */
+ 
+ static bool
+ vect_determine_min_output_precision_1 (stmt_vec_info stmt_info, tree lhs)
+ {
+   /* Take the maximum precision required by users of the result.  */
+   unsigned int precision = 0;
+   imm_use_iterator iter;
+   use_operand_p use;
+   FOR_EACH_IMM_USE_FAST (use, iter, lhs)
+     {
+       gimple *use_stmt = USE_STMT (use);
+       if (is_gimple_debug (use_stmt))
+ 	continue;
+       if (!vect_stmt_in_region_p (stmt_info->vinfo, use_stmt))
+ 	return false;
+       stmt_vec_info use_stmt_info = vinfo_for_stmt (use_stmt);
+       if (!use_stmt_info->min_input_precision)
+ 	return false;
+       precision = MAX (precision, use_stmt_info->min_input_precision);
+     }
+ 
+   if (dump_enabled_p ())
+     {
+       dump_printf_loc (MSG_NOTE, vect_location, "only the low %d bits of ",
+ 		       precision);
+       dump_generic_expr (MSG_NOTE, TDF_SLIM, lhs);
+       dump_printf (MSG_NOTE, " are significant\n");
+     }
+   stmt_info->min_output_precision = precision;
+   return true;
+ }
+ 
+ /* Calculate min_output_precision for STMT_INFO.  */
+ 
+ static void
+ vect_determine_min_output_precision (stmt_vec_info stmt_info)
+ {
+   /* We're only interested in statements with a narrowable result.  */
+   tree lhs = gimple_get_lhs (stmt_info->stmt);
+   if (!lhs
+       || TREE_CODE (lhs) != SSA_NAME
+       || !vect_narrowable_type_p (TREE_TYPE (lhs)))
+     return;
+ 
+   if (!vect_determine_min_output_precision_1 (stmt_info, lhs))
+     stmt_info->min_output_precision = TYPE_PRECISION (TREE_TYPE (lhs));
+ }
+ 
+ /* Use range information to decide whether STMT (described by STMT_INFO)
+    could be done in a narrower type.  This is effectively a forward
+    propagation, since it uses context-independent information that applies
+    to all users of an SSA name.  */
+ 
+ static void
+ vect_determine_precisions_from_range (stmt_vec_info stmt_info, gassign *stmt)
+ {
+   tree lhs = gimple_assign_lhs (stmt);
+   if (!lhs || TREE_CODE (lhs) != SSA_NAME)
+     return;
+ 
+   tree type = TREE_TYPE (lhs);
+   if (!vect_narrowable_type_p (type))
+     return;
+ 
+   /* First see whether we have any useful range information for the result.  */
+   unsigned int precision = TYPE_PRECISION (type);
+   signop sign = TYPE_SIGN (type);
+   wide_int min_value, max_value;
+   if (!vect_get_range_info (lhs, &min_value, &max_value))
+     return;
+ 
+   tree_code code = gimple_assign_rhs_code (stmt);
+   unsigned int nops = gimple_num_ops (stmt);
+ 
+   if (!vect_truncatable_operation_p (code))
+     /* Check that all relevant input operands are compatible, and update
+        [MIN_VALUE, MAX_VALUE] to include their ranges.  */
+     for (unsigned int i = 1; i < nops; ++i)
+       {
+ 	tree op = gimple_op (stmt, i);
+ 	if (TREE_CODE (op) == INTEGER_CST)
+ 	  {
+ 	    /* Don't require the integer to have RHS_TYPE (which it might
+ 	       not for things like shift amounts, etc.), but do require it
+ 	       to fit the type.  */
+ 	    if (!int_fits_type_p (op, type))
+ 	      return;
+ 
+ 	    min_value = wi::min (min_value, wi::to_wide (op, precision), sign);
+ 	    max_value = wi::max (max_value, wi::to_wide (op, precision), sign);
+ 	  }
+ 	else if (TREE_CODE (op) == SSA_NAME)
+ 	  {
+ 	    /* Ignore codes that don't take uniform arguments.  */
+ 	    if (!types_compatible_p (TREE_TYPE (op), type))
+ 	      return;
+ 
+ 	    wide_int op_min_value, op_max_value;
+ 	    if (!vect_get_range_info (op, &op_min_value, &op_max_value))
+ 	      return;
+ 
+ 	    min_value = wi::min (min_value, op_min_value, sign);
+ 	    max_value = wi::max (max_value, op_max_value, sign);
+ 	  }
+ 	else
+ 	  return;
+       }
+ 
+   /* Try to switch signed types for unsigned types if we can.
+      This is better for two reasons.  First, unsigned ops tend
+      to be cheaper than signed ops.  Second, it means that we can
+      handle things like:
+ 
+ 	signed char c;
+ 	int res = (int) c & 0xff00; // range [0x0000, 0xff00]
+ 
+      as:
+ 
+ 	signed char c;
+ 	unsigned short res_1 = (unsigned short) c & 0xff00;
+ 	int res = (int) res_1;
+ 
+      where the intermediate result res_1 has unsigned rather than
+      signed type.  */
+   if (sign == SIGNED && !wi::neg_p (min_value))
+     sign = UNSIGNED;
+ 
+   /* See what precision is required for MIN_VALUE and MAX_VALUE.  */
+   unsigned int precision1 = wi::min_precision (min_value, sign);
+   unsigned int precision2 = wi::min_precision (max_value, sign);
+   unsigned int value_precision = MAX (precision1, precision2);
+   if (value_precision >= precision)
+     return;
+ 
+   if (dump_enabled_p ())
+     {
+       dump_printf_loc (MSG_NOTE, vect_location, "can narrow to %s:%d"
+ 		       " without loss of precision: ",
+ 		       sign == SIGNED ? "signed" : "unsigned",
+ 		       value_precision);
+       dump_gimple_stmt (MSG_NOTE, TDF_SLIM, stmt, 0);
+     }
+ 
+   vect_set_operation_type (stmt_info, type, value_precision, sign);
+   vect_set_min_input_precision (stmt_info, type, value_precision);
+ }
+ 
+ /* Use information about the users of STMT's result to decide whether
+    STMT (described by STMT_INFO) could be done in a narrower type.
+    This is effectively a backward propagation.  */
+ 
+ static void
+ vect_determine_precisions_from_users (stmt_vec_info stmt_info, gassign *stmt)
+ {
+   tree_code code = gimple_assign_rhs_code (stmt);
+   unsigned int opno = (code == COND_EXPR ? 2 : 1);
+   tree type = TREE_TYPE (gimple_op (stmt, opno));
+   if (!vect_narrowable_type_p (type))
+     return;
+ 
+   unsigned int precision = TYPE_PRECISION (type);
+   unsigned int operation_precision, min_input_precision;
+   switch (code)
+     {
+     CASE_CONVERT:
+       /* Only the bits that contribute to the output matter.  Don't change
+ 	 the precision of the operation itself.  */
+       operation_precision = precision;
+       min_input_precision = stmt_info->min_output_precision;
+       break;
+ 
+     case LSHIFT_EXPR:
+     case RSHIFT_EXPR:
+       {
+ 	tree shift = gimple_assign_rhs2 (stmt);
+ 	if (TREE_CODE (shift) != INTEGER_CST
+ 	    || !wi::ltu_p (wi::to_widest (shift), precision))
+ 	  return;
+ 	unsigned int const_shift = TREE_INT_CST_LOW (shift);
+ 	if (code == LSHIFT_EXPR)
+ 	  {
+ 	    /* We need CONST_SHIFT fewer bits of the input.  */
+ 	    operation_precision = stmt_info->min_output_precision;
+ 	    min_input_precision = (MAX (operation_precision, const_shift)
+ 				    - const_shift);
+ 	  }
+ 	else
+ 	  {
+ 	    /* We need CONST_SHIFT extra bits to do the operation.  */
+ 	    operation_precision = (stmt_info->min_output_precision
+ 				   + const_shift);
+ 	    min_input_precision = operation_precision;
+ 	  }
+ 	break;
+       }
+ 
+     default:
+       if (vect_truncatable_operation_p (code))
+ 	{
+ 	  /* Input bit N has no effect on output bits N-1 and lower.  */
+ 	  operation_precision = stmt_info->min_output_precision;
+ 	  min_input_precision = operation_precision;
+ 	  break;
+ 	}
+       return;
+     }
+ 
+   if (operation_precision < precision)
+     {
+       if (dump_enabled_p ())
+ 	{
+ 	  dump_printf_loc (MSG_NOTE, vect_location, "can narrow to %s:%d"
+ 			   " without affecting users: ",
+ 			   TYPE_UNSIGNED (type) ? "unsigned" : "signed",
+ 			   operation_precision);
+ 	  dump_gimple_stmt (MSG_NOTE, TDF_SLIM, stmt, 0);
+ 	}
+       vect_set_operation_type (stmt_info, type, operation_precision,
+ 			       TYPE_SIGN (type));
+     }
+   vect_set_min_input_precision (stmt_info, type, min_input_precision);
+ }
+ 
+ /* Handle vect_determine_precisions for STMT_INFO, given that we
+    have already done so for the users of its result.  */
+ 
+ void
+ vect_determine_stmt_precisions (stmt_vec_info stmt_info)
+ {
+   vect_determine_min_output_precision (stmt_info);
+   if (gassign *stmt = dyn_cast <gassign *> (stmt_info->stmt))
+     {
+       vect_determine_precisions_from_range (stmt_info, stmt);
+       vect_determine_precisions_from_users (stmt_info, stmt);
+     }
+ }
+ 
+ /* Walk backwards through the vectorizable region to determine the
+    values of these fields:
+ 
+    - min_output_precision
+    - min_input_precision
+    - operation_precision
+    - operation_sign.  */
+ 
+ void
+ vect_determine_precisions (vec_info *vinfo)
+ {
+   DUMP_VECT_SCOPE ("vect_determine_precisions");
+ 
+   if (loop_vec_info loop_vinfo = dyn_cast <loop_vec_info> (vinfo))
+     {
+       struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
+       basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
+       unsigned int nbbs = loop->num_nodes;
+ 
+       for (unsigned int i = 0; i < nbbs; i++)
+ 	{
+ 	  basic_block bb = bbs[nbbs - i - 1];
+ 	  for (gimple_stmt_iterator si = gsi_last_bb (bb);
+ 	       !gsi_end_p (si); gsi_prev (&si))
+ 	    vect_determine_stmt_precisions (vinfo_for_stmt (gsi_stmt (si)));
+ 	}
+     }
+   else
+     {
+       bb_vec_info bb_vinfo = as_a <bb_vec_info> (vinfo);
+       gimple_stmt_iterator si = bb_vinfo->region_end;
+       gimple *stmt;
+       do
+ 	{
+ 	  if (!gsi_stmt (si))
+ 	    si = gsi_last_bb (bb_vinfo->bb);
+ 	  else
+ 	    gsi_prev (&si);
+ 	  stmt = gsi_stmt (si);
+ 	  stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
+ 	  if (stmt_info && STMT_VINFO_VECTORIZABLE (stmt_info))
+ 	    vect_determine_stmt_precisions (stmt_info);
+ 	}
+       while (stmt != gsi_stmt (bb_vinfo->region_begin));
+     }
+ }
+ 
  typedef gimple *(*vect_recog_func_ptr) (vec<gimple *> *, tree *);
  
  struct vect_recog_func
*************** struct vect_recog_func
*** 4157,4169 ****
     taken which means usually the more complex one needs to preceed the
     less comples onex (widen_sum only after dot_prod or sad for example).  */
  static vect_recog_func vect_vect_recog_func_ptrs[] = {
    { vect_recog_widen_mult_pattern, "widen_mult" },
    { vect_recog_dot_prod_pattern, "dot_prod" },
    { vect_recog_sad_pattern, "sad" },
    { vect_recog_widen_sum_pattern, "widen_sum" },
    { vect_recog_pow_pattern, "pow" },
    { vect_recog_widen_shift_pattern, "widen_shift" },
-   { vect_recog_over_widening_pattern, "over_widening" },
    { vect_recog_rotate_pattern, "rotate" },
    { vect_recog_vector_vector_shift_pattern, "vector_vector_shift" },
    { vect_recog_divmod_pattern, "divmod" },
--- 4505,4518 ----
     taken which means usually the more complex one needs to preceed the
     less comples onex (widen_sum only after dot_prod or sad for example).  */
  static vect_recog_func vect_vect_recog_func_ptrs[] = {
+   { vect_recog_over_widening_pattern, "over_widening" },
+   { vect_recog_cast_forwprop_pattern, "cast_forwprop" },
    { vect_recog_widen_mult_pattern, "widen_mult" },
    { vect_recog_dot_prod_pattern, "dot_prod" },
    { vect_recog_sad_pattern, "sad" },
    { vect_recog_widen_sum_pattern, "widen_sum" },
    { vect_recog_pow_pattern, "pow" },
    { vect_recog_widen_shift_pattern, "widen_shift" },
    { vect_recog_rotate_pattern, "rotate" },
    { vect_recog_vector_vector_shift_pattern, "vector_vector_shift" },
    { vect_recog_divmod_pattern, "divmod" },
*************** vect_pattern_recog (vec_info *vinfo)
*** 4437,4442 ****
--- 4786,4793 ----
    unsigned int i, j;
    auto_vec<gimple *, 1> stmts_to_replace;
  
+   vect_determine_precisions (vinfo);
+ 
    DUMP_VECT_SCOPE ("vect_pattern_recog");
  
    if (loop_vec_info loop_vinfo = dyn_cast <loop_vec_info> (vinfo))
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-1.c
===================================================================
*** gcc/testsuite/gcc.dg/vect/vect-over-widen-1.c	2018-06-20 11:36:19.000000000 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-1.c	2018-06-20 11:36:20.135890693 +0100
*************** int main (void)
*** 62,69 ****
  }
  
  /* { dg-final { scan-tree-dump-times "vect_recog_widen_shift_pattern: detected" 2 "vect" { target vect_widen_shift } } } */
! /* { dg-final { scan-tree-dump-times "vect_recog_over_widening_pattern: detected" 2 "vect" { target vect_widen_shift } } } */
! /* { dg-final { scan-tree-dump-times "vect_recog_over_widening_pattern: detected" 4 "vect" { target { { ! vect_sizes_32B_16B } && { ! vect_widen_shift } } } } } */
! /* { dg-final { scan-tree-dump-times "vect_recog_over_widening_pattern: detected" 8 "vect" { target vect_sizes_32B_16B } } } */
  /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
  
--- 62,70 ----
  }
  
  /* { dg-final { scan-tree-dump-times "vect_recog_widen_shift_pattern: detected" 2 "vect" { target vect_widen_shift } } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* << 3} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 3} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* << 8} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 5} "vect" } } */
  /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
  
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-1-big-array.c
===================================================================
*** gcc/testsuite/gcc.dg/vect/vect-over-widen-1-big-array.c	2018-06-20 11:36:19.000000000 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-1-big-array.c	2018-06-20 11:36:20.135890693 +0100
*************** int main (void)
*** 58,64 ****
  }
  
  /* { dg-final { scan-tree-dump-times "vect_recog_widen_shift_pattern: detected" 2 "vect" { target vect_widen_shift } } } */
! /* { dg-final { scan-tree-dump-times "vect_recog_over_widening_pattern: detected" 2 "vect" { target vect_widen_shift } } } */
! /* { dg-final { scan-tree-dump-times "vect_recog_over_widening_pattern: detected" 4 "vect" { target { ! vect_widen_shift } } } } */
  /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
  
--- 58,66 ----
  }
  
  /* { dg-final { scan-tree-dump-times "vect_recog_widen_shift_pattern: detected" 2 "vect" { target vect_widen_shift } } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* << 3} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 3} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* << 8} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 5} "vect" } } */
  /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
  
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-2.c
===================================================================
*** gcc/testsuite/gcc.dg/vect/vect-over-widen-2.c	2018-06-20 11:36:19.000000000 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-2.c	2018-06-20 11:36:20.135890693 +0100
*************** int main (void)
*** 57,63 ****
    return 0;
  }
  
! /* Final value stays in int, so no over-widening is detected at the moment.  */
! /* { dg-final { scan-tree-dump-times "vect_recog_over_widening_pattern: detected" 0 "vect" } } */
  /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
  
--- 57,68 ----
    return 0;
  }
  
! /* This is an over-widening even though the final result is still an int.
!    It's better to do one vector of ops on chars and then widen than to
!    widen and then do 4 vectors of ops on ints.  */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* << 3} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 3} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* << 8} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 5} "vect" } } */
  /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
  
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-2-big-array.c
===================================================================
*** gcc/testsuite/gcc.dg/vect/vect-over-widen-2-big-array.c	2018-06-20 11:36:19.000000000 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-2-big-array.c	2018-06-20 11:36:20.135890693 +0100
*************** int main (void)
*** 57,63 ****
    return 0;
  }
  
! /* Final value stays in int, so no over-widening is detected at the moment.  */
! /* { dg-final { scan-tree-dump-times "vect_recog_over_widening_pattern: detected" 0 "vect" } } */
  /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
  
--- 57,68 ----
    return 0;
  }
  
! /* This is an over-widening even though the final result is still an int.
!    It's better to do one vector of ops on chars and then widen than to
!    widen and then do 4 vectors of ops on ints.  */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* << 3} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 3} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* << 8} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 5} "vect" } } */
  /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
  
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-3.c
===================================================================
*** gcc/testsuite/gcc.dg/vect/vect-over-widen-3.c	2018-06-20 11:36:19.000000000 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-3.c	2018-06-20 11:36:20.135890693 +0100
*************** int main (void)
*** 57,62 ****
    return 0;
  }
  
! /* { dg-final { scan-tree-dump "vect_recog_over_widening_pattern: detected" "vect" } } */
  /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
  
--- 57,65 ----
    return 0;
  }
  
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* << 3} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 3} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 8} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* << 9} "vect" } } */
  /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
  
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-3-big-array.c
===================================================================
*** gcc/testsuite/gcc.dg/vect/vect-over-widen-3-big-array.c	2018-06-20 11:36:19.000000000 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-3-big-array.c	2018-06-20 11:36:20.135890693 +0100
*************** int main (void)
*** 59,65 ****
    return 0;
  }
  
! /* { dg-final { scan-tree-dump-times "vect_recog_over_widening_pattern: detected" 2 "vect" { target { ! vect_widen_shift } } } } */
! /* { dg-final { scan-tree-dump-times "vect_recog_over_widening_pattern: detected" 1 "vect" { target vect_widen_shift } } } */
  /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
  
--- 59,67 ----
    return 0;
  }
  
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* << 3} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 3} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 8} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* << 9} "vect" } } */
  /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
  
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-4.c
===================================================================
*** gcc/testsuite/gcc.dg/vect/vect-over-widen-4.c	2018-06-20 11:36:19.000000000 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-4.c	2018-06-20 11:36:20.135890693 +0100
*************** int main (void)
*** 66,73 ****
  }
  
  /* { dg-final { scan-tree-dump-times "vect_recog_widen_shift_pattern: detected" 2 "vect" { target vect_widen_shift } } } */
! /* { dg-final { scan-tree-dump-times "vect_recog_over_widening_pattern: detected" 2 "vect" { target vect_widen_shift } } } */
! /* { dg-final { scan-tree-dump-times "vect_recog_over_widening_pattern: detected" 4 "vect" { target { { ! vect_sizes_32B_16B } && { ! vect_widen_shift } } } } } */
! /* { dg-final { scan-tree-dump-times "vect_recog_over_widening_pattern: detected" 8 "vect" { target vect_sizes_32B_16B } } } */
  /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
  
--- 66,74 ----
  }
  
  /* { dg-final { scan-tree-dump-times "vect_recog_widen_shift_pattern: detected" 2 "vect" { target vect_widen_shift } } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* << 3} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 3} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* << 8} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 5} "vect" } } */
  /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
  
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-4-big-array.c
===================================================================
*** gcc/testsuite/gcc.dg/vect/vect-over-widen-4-big-array.c	2018-06-20 11:36:19.000000000 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-4-big-array.c	2018-06-20 11:36:20.135890693 +0100
*************** int main (void)
*** 62,68 ****
  }
  
  /* { dg-final { scan-tree-dump-times "vect_recog_widen_shift_pattern: detected" 2 "vect" { target vect_widen_shift } } } */
! /* { dg-final { scan-tree-dump-times "vect_recog_over_widening_pattern: detected" 2 "vect" { target vect_widen_shift } } } */
! /* { dg-final { scan-tree-dump-times "vect_recog_over_widening_pattern: detected" 4 "vect" { target { ! vect_widen_shift } } } } */
  /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
  
--- 62,70 ----
  }
  
  /* { dg-final { scan-tree-dump-times "vect_recog_widen_shift_pattern: detected" 2 "vect" { target vect_widen_shift } } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* << 3} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 3} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* << 8} "vect" } } */
! /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 5} "vect" } } */
  /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
  
Index: gcc/testsuite/gcc.dg/vect/bb-slp-over-widen-1.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/bb-slp-over-widen-1.c	2018-06-20 11:36:20.135890693 +0100
***************
*** 0 ****
--- 1,66 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #include "tree-vect.h"
+ 
+ /* Deliberate use of signed >>.  */
+ #define DEF_LOOP(SIGNEDNESS)			\
+   void __attribute__ ((noipa))			\
+   f_##SIGNEDNESS (SIGNEDNESS char *restrict a,	\
+ 		  SIGNEDNESS char *restrict b,	\
+ 		  SIGNEDNESS char *restrict c)	\
+   {						\
+     a[0] = (b[0] + c[0]) >> 1;			\
+     a[1] = (b[1] + c[1]) >> 1;			\
+     a[2] = (b[2] + c[2]) >> 1;			\
+     a[3] = (b[3] + c[3]) >> 1;			\
+     a[4] = (b[4] + c[4]) >> 1;			\
+     a[5] = (b[5] + c[5]) >> 1;			\
+     a[6] = (b[6] + c[6]) >> 1;			\
+     a[7] = (b[7] + c[7]) >> 1;			\
+     a[8] = (b[8] + c[8]) >> 1;			\
+     a[9] = (b[9] + c[9]) >> 1;			\
+     a[10] = (b[10] + c[10]) >> 1;		\
+     a[11] = (b[11] + c[11]) >> 1;		\
+     a[12] = (b[12] + c[12]) >> 1;		\
+     a[13] = (b[13] + c[13]) >> 1;		\
+     a[14] = (b[14] + c[14]) >> 1;		\
+     a[15] = (b[15] + c[15]) >> 1;		\
+   }
+ 
+ DEF_LOOP (signed)
+ DEF_LOOP (unsigned)
+ 
+ #define N 16
+ 
+ #define TEST_LOOP(SIGNEDNESS, BASE_B, BASE_C)		\
+   {							\
+     SIGNEDNESS char a[N], b[N], c[N];			\
+     for (int i = 0; i < N; ++i)				\
+       {							\
+ 	b[i] = BASE_B + i * 15;				\
+ 	c[i] = BASE_C + i * 14;				\
+ 	asm volatile ("" ::: "memory");			\
+       }							\
+     f_##SIGNEDNESS (a, b, c);				\
+     for (int i = 0; i < N; ++i)				\
+       if (a[i] != (BASE_B + BASE_C + i * 29) >> 1)	\
+ 	__builtin_abort ();				\
+   }
+ 
+ int
+ main (void)
+ {
+   check_vect ();
+ 
+   TEST_LOOP (signed, -128, -120);
+   TEST_LOOP (unsigned, 4, 10);
+ 
+   return 0;
+ }
+ 
+ /* { dg-final { scan-tree-dump "demoting int to signed short" "slp2" { target { ! vect_widen_shift } } } } */
+ /* { dg-final { scan-tree-dump "demoting int to unsigned short" "slp2" { target { ! vect_widen_shift } } } } */
+ /* { dg-final { scan-tree-dump-times "basic block vectorized" 2 "vect" } } */
Index: gcc/testsuite/gcc.dg/vect/bb-slp-over-widen-2.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/bb-slp-over-widen-2.c	2018-06-20 11:36:20.135890693 +0100
***************
*** 0 ****
--- 1,65 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #include "tree-vect.h"
+ 
+ /* Deliberate use of signed >>.  */
+ #define DEF_LOOP(SIGNEDNESS)			\
+   void __attribute__ ((noipa))			\
+   f_##SIGNEDNESS (SIGNEDNESS char *restrict a,	\
+ 		  SIGNEDNESS char *restrict b,	\
+ 		  SIGNEDNESS char c)		\
+   {						\
+     a[0] = (b[0] + c) >> 1;			\
+     a[1] = (b[1] + c) >> 1;			\
+     a[2] = (b[2] + c) >> 1;			\
+     a[3] = (b[3] + c) >> 1;			\
+     a[4] = (b[4] + c) >> 1;			\
+     a[5] = (b[5] + c) >> 1;			\
+     a[6] = (b[6] + c) >> 1;			\
+     a[7] = (b[7] + c) >> 1;			\
+     a[8] = (b[8] + c) >> 1;			\
+     a[9] = (b[9] + c) >> 1;			\
+     a[10] = (b[10] + c) >> 1;			\
+     a[11] = (b[11] + c) >> 1;			\
+     a[12] = (b[12] + c) >> 1;			\
+     a[13] = (b[13] + c) >> 1;			\
+     a[14] = (b[14] + c) >> 1;			\
+     a[15] = (b[15] + c) >> 1;			\
+   }
+ 
+ DEF_LOOP (signed)
+ DEF_LOOP (unsigned)
+ 
+ #define N 16
+ 
+ #define TEST_LOOP(SIGNEDNESS, BASE_B, C)		\
+   {							\
+     SIGNEDNESS char a[N], b[N], c[N];			\
+     for (int i = 0; i < N; ++i)				\
+       {							\
+ 	b[i] = BASE_B + i * 15;				\
+ 	asm volatile ("" ::: "memory");			\
+       }							\
+     f_##SIGNEDNESS (a, b, C);				\
+     for (int i = 0; i < N; ++i)				\
+       if (a[i] != (BASE_B + C + i * 15) >> 1)		\
+ 	__builtin_abort ();				\
+   }
+ 
+ int
+ main (void)
+ {
+   check_vect ();
+ 
+   TEST_LOOP (signed, -128, -120);
+   TEST_LOOP (unsigned, 4, 250);
+ 
+   return 0;
+ }
+ 
+ /* { dg-final { scan-tree-dump "demoting int to signed short" "slp2" { target { ! vect_widen_shift } } } } */
+ /* { dg-final { scan-tree-dump "demoting int to unsigned short" "slp2" { target { ! vect_widen_shift } } } } */
+ /* { dg-final { scan-tree-dump-times "basic block vectorized" 2 "vect" } } */
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-5.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-5.c	2018-06-20 11:36:20.135890693 +0100
***************
*** 0 ****
--- 1,51 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #include "tree-vect.h"
+ 
+ #ifndef SIGNEDNESS
+ #define SIGNEDNESS signed
+ #define BASE_B -128
+ #define BASE_C -100
+ #endif
+ 
+ #define N 50
+ 
+ /* Both range analysis and backward propagation from the truncation show
+    that these calculations can be done in SIGNEDNESS short.  */
+ void __attribute__ ((noipa))
+ f (SIGNEDNESS char *restrict a, SIGNEDNESS char *restrict b,
+    SIGNEDNESS char *restrict c)
+ {
+   /* Deliberate use of signed >>.  */
+   for (int i = 0; i < N; ++i)
+     a[i] = (b[i] + c[i]) >> 1;
+ }
+ 
+ int
+ main (void)
+ {
+   check_vect ();
+ 
+   SIGNEDNESS char a[N], b[N], c[N];
+   for (int i = 0; i < N; ++i)
+     {
+       b[i] = BASE_B + i * 5;
+       c[i] = BASE_C + i * 4;
+       asm volatile ("" ::: "memory");
+     }
+   f (a, b, c);
+   for (int i = 0; i < N; ++i)
+     if (a[i] != (BASE_B + BASE_C + i * 9) >> 1)
+       __builtin_abort ();
+ 
+   return 0;
+ }
+ 
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* \+ } "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 1} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_cast_forwprop_pattern: detected:[^\n]* \(signed char\)} "vect" } } */
+ /* { dg-final { scan-tree-dump-not {vector[^ ]* int} "vect" } } */
+ /* { dg-final { scan-tree-dump-times "vectorized 1 loop" 1 "vect" } } */
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-6.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-6.c	2018-06-20 11:36:20.139890658 +0100
***************
*** 0 ****
--- 1,16 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #define SIGNEDNESS unsigned
+ #define BASE_B 4
+ #define BASE_C 40
+ 
+ #include "vect-over-widen-5.c"
+ 
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* \+ } "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 1} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_cast_forwprop_pattern: detected:[^\n]* \(unsigned char\)} "vect" } } */
+ /* { dg-final { scan-tree-dump-not {vector[^ ]* int} "vect" } } */
+ /* { dg-final { scan-tree-dump-times "vectorized 1 loop" 1 "vect" } } */
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-7.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-7.c	2018-06-20 11:36:20.139890658 +0100
***************
*** 0 ****
--- 1,53 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #include "tree-vect.h"
+ 
+ #ifndef SIGNEDNESS
+ #define SIGNEDNESS signed
+ #define BASE_B -128
+ #define BASE_C -100
+ #define D -120
+ #endif
+ 
+ #define N 50
+ 
+ /* Both range analysis and backward propagation from the truncation show
+    that these calculations can be done in SIGNEDNESS short.  */
+ void __attribute__ ((noipa))
+ f (SIGNEDNESS char *restrict a, SIGNEDNESS char *restrict b,
+    SIGNEDNESS char *restrict c, SIGNEDNESS char d)
+ {
+   int promoted_d = d;
+   for (int i = 0; i < N; ++i)
+     /* Deliberate use of signed >>.  */
+     a[i] = (b[i] + c[i] + promoted_d) >> 2;
+ }
+ 
+ int
+ main (void)
+ {
+   check_vect ();
+ 
+   SIGNEDNESS char a[N], b[N], c[N];
+   for (int i = 0; i < N; ++i)
+     {
+       b[i] = BASE_B + i * 5;
+       c[i] = BASE_C + i * 4;
+       asm volatile ("" ::: "memory");
+     }
+   f (a, b, c, D);
+   for (int i = 0; i < N; ++i)
+     if (a[i] != (BASE_B + BASE_C + D + i * 9) >> 2)
+       __builtin_abort ();
+ 
+   return 0;
+ }
+ 
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* \+ } "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 2} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_cast_forwprop_pattern: detected:[^\n]* \(signed char\)} "vect" } } */
+ /* { dg-final { scan-tree-dump-not {vector[^ ]* int} "vect" } } */
+ /* { dg-final { scan-tree-dump-times "vectorized 1 loop" 1 "vect" } } */
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-8.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-8.c	2018-06-20 11:36:20.139890658 +0100
***************
*** 0 ****
--- 1,19 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #ifndef SIGNEDNESS
+ #define SIGNEDNESS unsigned
+ #define BASE_B 4
+ #define BASE_C 40
+ #define D 251
+ #endif
+ 
+ #include "vect-over-widen-7.c"
+ 
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* \+ } "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 2} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_cast_forwprop_pattern: detected:[^\n]* \(unsigned char\)} "vect" } } */
+ /* { dg-final { scan-tree-dump-not {vector[^ ]* int} "vect" } } */
+ /* { dg-final { scan-tree-dump-times "vectorized 1 loop" 1 "vect" } } */
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-9.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-9.c	2018-06-20 11:36:20.139890658 +0100
***************
*** 0 ****
--- 1,58 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #include "tree-vect.h"
+ 
+ #ifndef SIGNEDNESS
+ #define SIGNEDNESS signed
+ #define BASE_B -128
+ #define BASE_C -100
+ #endif
+ 
+ #define N 50
+ 
+ /* Both range analysis and backward propagation from the truncation show
+    that these calculations can be done in SIGNEDNESS short.  */
+ void __attribute__ ((noipa))
+ f (SIGNEDNESS char *restrict a, SIGNEDNESS char *restrict b,
+    SIGNEDNESS char *restrict c)
+ {
+   for (int i = 0; i < N; ++i)
+     {
+       /* Deliberate use of signed >>.  */
+       int res = b[i] + c[i];
+       a[i] = (res + (res >> 1)) >> 2;
+     }
+ }
+ 
+ int
+ main (void)
+ {
+   check_vect ();
+ 
+   SIGNEDNESS char a[N], b[N], c[N];
+   for (int i = 0; i < N; ++i)
+     {
+       b[i] = BASE_B + i * 5;
+       c[i] = BASE_C + i * 4;
+       asm volatile ("" ::: "memory");
+     }
+   f (a, b, c);
+   for (int i = 0; i < N; ++i)
+     {
+       int res = BASE_B + BASE_C + i * 9;
+       if (a[i] != ((res + (res >> 1)) >> 2))
+ 	__builtin_abort ();
+     }
+ 
+   return 0;
+ }
+ 
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* \+ } "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 1} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 2} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_cast_forwprop_pattern: detected:[^\n]* \(signed char\)} "vect" } } */
+ /* { dg-final { scan-tree-dump-not {vector[^ ]* int} "vect" } } */
+ /* { dg-final { scan-tree-dump-times "vectorized 1 loop" 1 "vect" } } */
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-10.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-10.c	2018-06-20 11:36:20.135890693 +0100
***************
*** 0 ****
--- 1,19 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #ifndef SIGNEDNESS
+ #define SIGNEDNESS unsigned
+ #define BASE_B 4
+ #define BASE_C 40
+ #endif
+ 
+ #include "vect-over-widen-9.c"
+ 
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* \+ } "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 1} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 2} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_cast_forwprop_pattern: detected:[^\n]* \(unsigned char\)} "vect" } } */
+ /* { dg-final { scan-tree-dump-not {vector[^ ]* int} "vect" } } */
+ /* { dg-final { scan-tree-dump-times "vectorized 1 loop" 1 "vect" } } */
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-11.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-11.c	2018-06-20 11:36:20.135890693 +0100
***************
*** 0 ****
--- 1,63 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #include "tree-vect.h"
+ 
+ #ifndef SIGNEDNESS
+ #define SIGNEDNESS signed
+ #define BASE_B -128
+ #define BASE_C -100
+ #endif
+ 
+ #define N 50
+ 
+ /* Both range analysis and backward propagation from the truncation show
+    that these calculations can be done in SIGNEDNESS short, with "res"
+    being extended for the store to d[i].  */
+ void __attribute__ ((noipa))
+ f (SIGNEDNESS char *restrict a, SIGNEDNESS char *restrict b,
+    SIGNEDNESS char *restrict c, int *restrict d)
+ {
+   for (int i = 0; i < N; ++i)
+     {
+       /* Deliberate use of signed >>.  */
+       int res = b[i] + c[i];
+       a[i] = (res + (res >> 1)) >> 2;
+       d[i] = res;
+     }
+ }
+ 
+ int
+ main (void)
+ {
+   check_vect ();
+ 
+   SIGNEDNESS char a[N], b[N], c[N];
+   int d[N];
+   for (int i = 0; i < N; ++i)
+     {
+       b[i] = BASE_B + i * 5;
+       c[i] = BASE_C + i * 4;
+       asm volatile ("" ::: "memory");
+     }
+   f (a, b, c, d);
+   for (int i = 0; i < N; ++i)
+     {
+       int res = BASE_B + BASE_C + i * 9;
+       if (a[i] != ((res + (res >> 1)) >> 2))
+ 	__builtin_abort ();
+       if (d[i] != res)
+ 	__builtin_abort ();
+     }
+ 
+   return 0;
+ }
+ 
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* \+ } "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 1} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 2} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_cast_forwprop_pattern: detected:[^\n]* \(signed char\)} "vect" } } */
+ /* { dg-final { scan-tree-dump {vector[^ ]* int} "vect" } } */
+ /* { dg-final { scan-tree-dump-times "vectorized 1 loop" 1 "vect" } } */
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-12.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-12.c	2018-06-20 11:36:20.135890693 +0100
***************
*** 0 ****
--- 1,19 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #ifndef SIGNEDNESS
+ #define SIGNEDNESS unsigned
+ #define BASE_B 4
+ #define BASE_C 40
+ #endif
+ 
+ #include "vect-over-widen-11.c"
+ 
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* \+ } "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 1} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 2} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_cast_forwprop_pattern: detected:[^\n]* \(unsigned char\)} "vect" } } */
+ /* { dg-final { scan-tree-dump {vector[^ ]* int} "vect" } } */
+ /* { dg-final { scan-tree-dump-times "vectorized 1 loop" 1 "vect" } } */
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-13.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-13.c	2018-06-20 11:36:20.135890693 +0100
***************
*** 0 ****
--- 1,50 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #include "tree-vect.h"
+ 
+ #ifndef SIGNEDNESS
+ #define SIGNEDNESS signed
+ #define BASE_B -128
+ #define BASE_C -120
+ #endif
+ 
+ #define N 50
+ 
+ /* We rely on range analysis to show that these calculations can be done
+    in SIGNEDNESS short.  */
+ void __attribute__ ((noipa))
+ f (SIGNEDNESS char *restrict a, SIGNEDNESS char *restrict b,
+    SIGNEDNESS char *restrict c)
+ {
+   for (int i = 0; i < N; ++i)
+     a[i] = (b[i] + c[i]) / 2;
+ }
+ 
+ int
+ main (void)
+ {
+   check_vect ();
+ 
+   SIGNEDNESS char a[N], b[N], c[N];
+   for (int i = 0; i < N; ++i)
+     {
+       b[i] = BASE_B + i * 5;
+       c[i] = BASE_C + i * 4;
+       asm volatile ("" ::: "memory");
+     }
+   f (a, b, c);
+   for (int i = 0; i < N; ++i)
+     if (a[i] != (BASE_B + BASE_C + i * 9) / 2)
+       __builtin_abort ();
+ 
+   return 0;
+ }
+ 
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* \+} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* / 2} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_cast_forwprop_pattern: detected:[^\n]* = \(signed char\)} "vect" } } */
+ /* { dg-final { scan-tree-dump-not {vector[^ ]* int} "vect" } } */
+ /* { dg-final { scan-tree-dump-times "vectorized 1 loop" 1 "vect" } } */
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-14.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-14.c	2018-06-20 11:36:20.135890693 +0100
***************
*** 0 ****
--- 1,18 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #ifndef SIGNEDNESS
+ #define SIGNEDNESS unsigned
+ #define BASE_B 4
+ #define BASE_C 40
+ #endif
+ 
+ #include "vect-over-widen-13.c"
+ 
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* \+} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 1} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_cast_forwprop_pattern: detected:[^\n]* = \(unsigned char\)} "vect" } } */
+ /* { dg-final { scan-tree-dump-not {vector[^ ]* int} "vect" } } */
+ /* { dg-final { scan-tree-dump-times "vectorized 1 loop" 1 "vect" } } */
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-15.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-15.c	2018-06-20 11:36:20.135890693 +0100
***************
*** 0 ****
--- 1,52 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #include "tree-vect.h"
+ 
+ #ifndef SIGNEDNESS
+ #define SIGNEDNESS signed
+ #define BASE_B -128
+ #define BASE_C -120
+ #endif
+ 
+ #define N 50
+ 
+ /* We rely on range analysis to show that these calculations can be done
+    in SIGNEDNESS short, with the result being extended to int for the
+    store.  */
+ void __attribute__ ((noipa))
+ f (int *restrict a, SIGNEDNESS char *restrict b,
+    SIGNEDNESS char *restrict c)
+ {
+   for (int i = 0; i < N; ++i)
+     a[i] = (b[i] + c[i]) / 2;
+ }
+ 
+ int
+ main (void)
+ {
+   check_vect ();
+ 
+   int a[N];
+   SIGNEDNESS char b[N], c[N];
+   for (int i = 0; i < N; ++i)
+     {
+       b[i] = BASE_B + i * 5;
+       c[i] = BASE_C + i * 4;
+       asm volatile ("" ::: "memory");
+     }
+   f (a, b, c);
+   for (int i = 0; i < N; ++i)
+     if (a[i] != (BASE_B + BASE_C + i * 9) / 2)
+       __builtin_abort ();
+ 
+   return 0;
+ }
+ 
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* \+} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* / 2} "vect" } } */
+ /* { dg-final { scan-tree-dump-not {vect_recog_cast_forwprop_pattern: detected} "vect" } } */
+ /* { dg-final { scan-tree-dump {vector[^ ]* int} "vect" } } */
+ /* { dg-final { scan-tree-dump-times "vectorized 1 loop" 1 "vect" } } */
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-16.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-16.c	2018-06-20 11:36:20.135890693 +0100
***************
*** 0 ****
--- 1,18 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #ifndef SIGNEDNESS
+ #define SIGNEDNESS unsigned
+ #define BASE_B 4
+ #define BASE_C 40
+ #endif
+ 
+ #include "vect-over-widen-15.c"
+ 
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* \+} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* >> 1} "vect" } } */
+ /* { dg-final { scan-tree-dump-not {vect_recog_cast_forwprop_pattern: detected} "vect" } } */
+ /* { dg-final { scan-tree-dump {vector[^ ]* int} "vect" } } */
+ /* { dg-final { scan-tree-dump-times "vectorized 1 loop" 1 "vect" } } */
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-17.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-17.c	2018-06-20 11:36:20.135890693 +0100
***************
*** 0 ****
--- 1,46 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #include "tree-vect.h"
+ 
+ #define N 1024
+ 
+ /* This should not be treated as an over-widening pattern, even though
+    "(b[i] & 0xef) | 0x80)" could be done in unsigned chars.  */
+ 
+ void __attribute__ ((noipa))
+ f (unsigned short *restrict a, unsigned short *restrict b)
+ {
+   for (__INTPTR_TYPE__ i = 0; i < N; ++i)
+     {
+       unsigned short foo = ((b[i] & 0xef) | 0x80) + (a[i] << 4);
+       a[i] = foo;
+     }
+ }
+ 
+ int
+ main (void)
+ {
+   check_vect ();
+ 
+   unsigned short a[N], b[N];
+   for (int i = 0; i < N; ++i)
+     {
+       a[i] = i;
+       b[i] = i * 3;
+       asm volatile ("" ::: "memory");
+     }
+   f (a, b);
+   for (int i = 0; i < N; ++i)
+     if (a[i] != ((((i * 3) & 0xef) | 0x80) + (i << 4)))
+       __builtin_abort ();
+ 
+   return 0;
+ }
+ 
+ /* { dg-final { scan-tree-dump-not {vect_recog_over_widening_pattern: detected} "vect" } } */
+ /* { dg-final { scan-tree-dump-not {vector[^\n]*char} "vect" } } */
+ /* { dg-final { scan-tree-dump-not {vector[^ ]* int} "vect" } } */
+ /* { dg-final { scan-tree-dump-times "vectorized 1 loop" 1 "vect" } } */
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-18.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-18.c	2018-06-20 11:36:20.135890693 +0100
***************
*** 0 ****
--- 1,50 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #include "tree-vect.h"
+ 
+ #define N 1024
+ 
+ /* This should be treated as an over-widening pattern: we can truncate
+    b to unsigned char after loading it and do all the computation in
+    unsigned char.  */
+ 
+ void __attribute__ ((noipa))
+ f (unsigned char *restrict a, unsigned short *restrict b)
+ {
+   for (__INTPTR_TYPE__ i = 0; i < N; ++i)
+     {
+       unsigned short foo = ((b[i] & 0xef) | 0x80) + (a[i] << 4);
+       a[i] = foo;
+     }
+ }
+ 
+ int
+ main (void)
+ {
+   check_vect ();
+ 
+   unsigned char a[N];
+   unsigned short b[N];
+   for (int i = 0; i < N; ++i)
+     {
+       a[i] = i;
+       b[i] = i * 3;
+       asm volatile ("" ::: "memory");
+     }
+   f (a, b);
+   for (int i = 0; i < N; ++i)
+     if (a[i] != (unsigned char) ((((i * 3) & 0xef) | 0x80) + (i << 4)))
+       __builtin_abort ();
+ 
+   return 0;
+ }
+ 
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* &} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* |} "vect" } } */
+ /* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* <<} "vect" } } */
+ /* { dg-final { scan-tree-dump {vector[^\n]*char} "vect" } } */
+ /* { dg-final { scan-tree-dump-not {vector[^ ]* int} "vect" } } */
+ /* { dg-final { scan-tree-dump-times "vectorized 1 loop" 1 "vect" } } */
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-19.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-19.c	2018-06-20 11:36:20.135890693 +0100
***************
*** 0 ****
--- 1,53 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #include "tree-vect.h"
+ 
+ #define N 111
+ 
+ /* This shouldn't be treated as an over-widening operation: it's better
+    to reuse the extensions of di and ei for di + ei than to add them
+    as shorts and introduce a third extension.  */
+ 
+ void __attribute__ ((noipa))
+ f (unsigned int *restrict a, unsigned int *restrict b,
+    unsigned int *restrict c, unsigned char *restrict d,
+    unsigned char *restrict e)
+ {
+   for (__INTPTR_TYPE__ i = 0; i < N; ++i)
+     {
+       unsigned int di = d[i];
+       unsigned int ei = e[i];
+       a[i] = di;
+       b[i] = ei;
+       c[i] = di + ei;
+     }
+ }
+ 
+ int
+ main (void)
+ {
+   check_vect ();
+ 
+   unsigned int a[N], b[N], c[N];
+   unsigned char d[N], e[N];
+   for (int i = 0; i < N; ++i)
+     {
+       d[i] = i * 2 + 3;
+       e[i] = i + 100;
+       asm volatile ("" ::: "memory");
+     }
+   f (a, b, c, d, e);
+   for (int i = 0; i < N; ++i)
+     if (a[i] != i * 2 + 3
+ 	|| b[i] != i + 100
+ 	|| c[i] != i * 3 + 103)
+       __builtin_abort ();
+ 
+   return 0;
+ }
+ 
+ /* { dg-final { scan-tree-dump-not {vect_recog_over_widening_pattern: detected} "vect" } } */
+ /* { dg-final { scan-tree-dump-times "vectorized 1 loop" 1 "vect" } } */
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-20.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-20.c	2018-06-20 11:36:20.135890693 +0100
***************
*** 0 ****
--- 1,53 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #include "tree-vect.h"
+ 
+ #define N 111
+ 
+ /* This shouldn't be treated as an over-widening operation: it's better
+    to reuse the extensions of di and ei for di + ei than to add them
+    as shorts and introduce a third extension.  */
+ 
+ void __attribute__ ((noipa))
+ f (unsigned int *restrict a, unsigned int *restrict b,
+    unsigned int *restrict c, unsigned char *restrict d,
+    unsigned char *restrict e)
+ {
+   for (__INTPTR_TYPE__ i = 0; i < N; ++i)
+     {
+       int di = d[i];
+       int ei = e[i];
+       a[i] = di;
+       b[i] = ei;
+       c[i] = di + ei;
+     }
+ }
+ 
+ int
+ main (void)
+ {
+   check_vect ();
+ 
+   unsigned int a[N], b[N], c[N];
+   unsigned char d[N], e[N];
+   for (int i = 0; i < N; ++i)
+     {
+       d[i] = i * 2 + 3;
+       e[i] = i + 100;
+       asm volatile ("" ::: "memory");
+     }
+   f (a, b, c, d, e);
+   for (int i = 0; i < N; ++i)
+     if (a[i] != i * 2 + 3
+ 	|| b[i] != i + 100
+ 	|| c[i] != i * 3 + 103)
+       __builtin_abort ();
+ 
+   return 0;
+ }
+ 
+ /* { dg-final { scan-tree-dump-not {vect_recog_over_widening_pattern: detected} "vect" } } */
+ /* { dg-final { scan-tree-dump-times "vectorized 1 loop" 1 "vect" } } */
Index: gcc/testsuite/gcc.dg/vect/vect-over-widen-21.c
===================================================================
*** /dev/null	2018-06-13 14:36:57.192460992 +0100
--- gcc/testsuite/gcc.dg/vect/vect-over-widen-21.c	2018-06-20 11:36:20.135890693 +0100
***************
*** 0 ****
--- 1,51 ----
+ /* { dg-require-effective-target vect_int } */
+ /* { dg-require-effective-target vect_shift } */
+ /* { dg-require-effective-target vect_pack_trunc } */
+ /* { dg-require-effective-target vect_unpack } */
+ 
+ #include "tree-vect.h"
+ 
+ #define N 111
+ 
+ /* This shouldn't be treated as an over-widening operation: it's better
+    to reuse the extensions of di and ei for di + ei than to add them
+    as shorts and introduce a third extension.  */
+ 
+ void __attribute__ ((noipa))
+ f (unsigned int *restrict a, unsigned int *restrict b,
+    unsigned int *restrict c, unsigned char *restrict d,
+    unsigned char *restrict e)
+ {
+   for (__INTPTR_TYPE__ i = 0; i < N; ++i)
+     {
+       a[i] = d[i];
+       b[i] = e[i];
+       c[i] = d[i] + e[i];
+     }
+ }
+ 
+ int
+ main (void)
+ {
+   check_vect ();
+ 
+   unsigned int a[N], b[N], c[N];
+   unsigned char d[N], e[N];
+   for (int i = 0; i < N; ++i)
+     {
+       d[i] = i * 2 + 3;
+       e[i] = i + 100;
+       asm volatile ("" ::: "memory");
+     }
+   f (a, b, c, d, e);
+   for (int i = 0; i < N; ++i)
+     if (a[i] != i * 2 + 3
+ 	|| b[i] != i + 100
+ 	|| c[i] != i * 3 + 103)
+       __builtin_abort ();
+ 
+   return 0;
+ }
+ 
+ /* { dg-final { scan-tree-dump-not {vect_recog_over_widening_pattern: detected} "vect" } } */
+ /* { dg-final { scan-tree-dump-times "vectorized 1 loop" 1 "vect" } } */



More information about the Gcc-patches mailing list