This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [patch] Lno branch merge part 7 -- tree level invariant motion
Hello,
> On Tue, Jul 06, 2004 at 04:15:42PM +0200, Zdenek Dvorak wrote:
> > + bool
> > + for_each_index (tree *addr_p, bool (*cbck) (tree, tree *, void *), void *data)
>
> This doesn't handle ARRAY_RANGE_REF or VIEW_CONVERT_EXPR.
because I don't know they exist (they never showed up when I used to
have default: abort (); clause in the switch).
> Does it
> need to do anything special for ARRAY_REF with variable lower bound
I don't think so; this function just iterates over all indices in the
memory reference.
> or varible stride?
What's that?
> > + /* Returns true if MEM is a memory access that might cause error. */
> > +
> > + static bool
> > + unsafe_memory_access_p (tree mem)
>
> I believe this is tree_could_trap_p ...
As far as I see, tree_could_trap_p will never say you that ARRAY_REF
access traps; otherwise I also think so (as far as I remember, the
reason for having unsafe_memory_access_p was that in the time I wrote
this part, tree_could_trap_p did nothing but checking for div_exprs).
> > + return !in_array_bounds_p (base, idx);
>
> ... except for this. Is this necessary? It would be if you're
> moving a store out of a possibly-zero-trip loop, sure. Assuming
> it is necessary, can we share code with tree_could_trap_p?
Not strictly necessary, but it enables you to move more invariants
out of the loops.
> > + || tree_could_trap_p (rhs)
> > + || unsafe_memory_access_p (rhs))
>
> Hum. You're already calling both. In which case we definitely
> should figure out how to share code.
Sure; I think we just need to fix handling of array_refs in
tree_could_trap_p and it should be possible to use it, then.
> I think your handling of
> INDIRECT_REF, for instance, is incorrect.
It is definitely conservatively correct.
> > + determine_max_movement (tree stmt, bool must_preserve_exec)
> ...
> > + for (i = 0; i < NUM_USES (uses); i++)
> > + for (i = 0; i < NUM_VUSES (vuses); i++)
> > + for (i = 0; i < NUM_V_MAY_DEFS (v_may_defs); i++)
>
> Missing MUST_DEFS? If not, add a comment why.
Because we obviously are interested only in uses of statement.
> > + static tree
> > + single_reachable_address (struct loop *loop, tree stmt,
> > + struct mem_ref **mem_refs)
> ...
> > + for (i = 0; i < NUM_V_MAY_DEFS (v_may_defs); i++)
> > + for (i = 0; i < NUM_VUSES (vuses); i++)
>
> MUST_DEFS again?
Since we are interested only in virtual uses (and comment is already there).
> > + /* Set ALWAYS_EXECUTED_IN for each block. Quadratic, can be improved. */
>
> You're not processing any statement more than once.
> How is that quadratic?
I am not really sure why this comment is there; the only quadratic
behavior I see is that fill_always_executed_in is executed for each loop
and it is linear in size of the loop body, but this should not be a
problem in practice.
Anyway, here is the (not fully tested yet) patch reflecting those of the
changes you suggest I was able to do without further discussion.
Zdenek
Index: Makefile.in
===================================================================
RCS file: /cvs/gcc/gcc/gcc/Makefile.in,v
retrieving revision 1.1321
diff -c -3 -p -r1.1321 Makefile.in
*** Makefile.in 8 Jul 2004 08:19:58 -0000 1.1321
--- Makefile.in 8 Jul 2004 15:52:50 -0000
*************** OBJS-common = \
*** 899,905 ****
cfg.o cfganal.o cfgbuild.o cfgcleanup.o cfglayout.o cfgloop.o \
cfgloopanal.o cfgloopmanip.o loop-init.o loop-unswitch.o loop-unroll.o \
cfgrtl.o combine.o conflict.o convert.o coverage.o cse.o cselib.o \
! dbxout.o ddg.o tree-ssa-loop-ch.o loop-invariant.o \
debug.o df.o diagnostic.o dojump.o dominance.o loop-doloop.o \
dwarf2asm.o dwarf2out.o emit-rtl.o except.o explow.o loop-iv.o \
expmed.o expr.o final.o flow.o fold-const.o function.o gcse.o \
--- 899,905 ----
cfg.o cfganal.o cfgbuild.o cfgcleanup.o cfglayout.o cfgloop.o \
cfgloopanal.o cfgloopmanip.o loop-init.o loop-unswitch.o loop-unroll.o \
cfgrtl.o combine.o conflict.o convert.o coverage.o cse.o cselib.o \
! dbxout.o ddg.o tree-ssa-loop-ch.o loop-invariant.o tree-ssa-loop-im.o \
debug.o df.o diagnostic.o dojump.o dominance.o loop-doloop.o \
dwarf2asm.o dwarf2out.o emit-rtl.o except.o explow.o loop-iv.o \
expmed.o expr.o final.o flow.o fold-const.o function.o gcse.o \
*************** tree-ssa-loop-ch.o : tree-ssa-loop-ch.c
*** 1680,1685 ****
--- 1680,1689 ----
$(SYSTEM_H) $(RTL_H) $(TREE_H) $(TM_P_H) $(CFGLOOP_H) tree-inline.h \
output.h diagnostic.h $(TIMEVAR_H) $(TM_H) coretypes.h $(TREE_DUMP_H) \
tree-pass.h flags.h
+ tree-ssa-loop-im.o : tree-ssa-loop-im.c $(TREE_FLOW_H) $(CONFIG_H) \
+ $(SYSTEM_H) $(RTL_H) $(TREE_H) $(TM_P_H) $(CFGLOOP_H) domwalk.h $(PARAMS_H)\
+ output.h diagnostic.h $(TIMEVAR_H) $(TM_H) coretypes.h $(TREE_DUMP_H) \
+ tree-pass.h flags.h
tree-ssa-alias.o : tree-ssa-alias.c $(TREE_FLOW_H) $(CONFIG_H) $(SYSTEM_H) \
$(RTL_H) $(TREE_H) $(TM_P_H) $(EXPR_H) $(GGC_H) tree-inline.h $(FLAGS_H) \
function.h $(TIMEVAR_H) tree-alias-common.h convert.h $(TM_H) coretypes.h \
Index: cfgloop.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cfgloop.c,v
retrieving revision 1.32
diff -c -3 -p -r1.32 cfgloop.c
*** cfgloop.c 13 May 2004 06:39:32 -0000 1.32
--- cfgloop.c 8 Jul 2004 15:52:50 -0000
*************** flow_loop_nested_p (const struct loop *o
*** 101,106 ****
--- 101,120 ----
&& loop->pred[outer->depth] == outer;
}
+ /* Returns superloop of LOOP at given DEPTH. */
+
+ struct loop *
+ superloop_at_depth (struct loop *loop, unsigned depth)
+ {
+ if (depth > (unsigned) loop->depth)
+ abort ();
+
+ if (depth == (unsigned) loop->depth)
+ return loop;
+
+ return loop->pred[depth];
+ }
+
/* Dump the loop information specified by LOOP to the stream FILE
using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
Index: cfgloop.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cfgloop.h,v
retrieving revision 1.20
diff -c -3 -p -r1.20 cfgloop.h
*** cfgloop.h 20 Jun 2004 21:31:28 -0000 1.20
--- cfgloop.h 8 Jul 2004 15:52:50 -0000
*************** extern bool flow_loop_outside_edge_p (co
*** 253,258 ****
--- 253,259 ----
extern bool flow_loop_nested_p (const struct loop *, const struct loop *);
extern bool flow_bb_inside_loop_p (const struct loop *, const basic_block);
extern struct loop * find_common_loop (struct loop *, struct loop *);
+ struct loop *superloop_at_depth (struct loop *, unsigned);
extern int num_loop_insns (struct loop *);
extern int average_num_loop_insns (struct loop *);
extern unsigned get_loop_level (const struct loop *);
Index: common.opt
===================================================================
RCS file: /cvs/gcc/gcc/gcc/common.opt,v
retrieving revision 1.39
diff -c -3 -p -r1.39 common.opt
*** common.opt 30 Jun 2004 21:28:59 -0000 1.39
--- common.opt 8 Jul 2004 15:52:50 -0000
*************** ftree-fre
*** 777,782 ****
--- 777,786 ----
Common Report Var(flag_tree_fre)
Enable Full Redundancy Elimination (FRE) on trees
+ ftree-lim
+ Common Report Var(flag_tree_lim) Init(1)
+ Enable loop invariant motion on trees
+
ftree-loop-optimize
Common Report Var(flag_tree_loop_optimize) Init(1)
Enable loop optimizations on tree level
Index: params.def
===================================================================
RCS file: /cvs/gcc/gcc/gcc/params.def,v
retrieving revision 1.41
diff -c -3 -p -r1.41 params.def
*** params.def 25 May 2004 12:54:54 -0000 1.41
--- params.def 8 Jul 2004 15:52:50 -0000
*************** DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
*** 304,309 ****
--- 304,316 ----
"The maximum length of path considered in cse",
10)
+ /* The cost of expression in loop invariant motion that is considered
+ expensive. */
+ DEFPARAM(PARAM_LIM_EXPENSIVE,
+ "lim-expensive",
+ "The minimum cost of an expensive expression in the loop invariant motion",
+ 20)
+
/* The product of the next two is used to decide whether or not to
use .GLOBAL_VAR. See tree-dfa.c. */
DEFPARAM(PARAM_GLOBAL_VAR_THRESHOLD,
Index: timevar.def
===================================================================
RCS file: /cvs/gcc/gcc/gcc/timevar.def,v
retrieving revision 1.29
diff -c -3 -p -r1.29 timevar.def
*** timevar.def 29 Jun 2004 01:53:03 -0000 1.29
--- timevar.def 8 Jul 2004 15:52:50 -0000
*************** DEFTIMEVAR (TV_TREE_DCE , "tree co
*** 82,87 ****
--- 82,88 ----
DEFTIMEVAR (TV_TREE_CD_DCE , "tree aggressive DCE")
DEFTIMEVAR (TV_TREE_DSE , "tree DSE")
DEFTIMEVAR (TV_TREE_LOOP , "tree loop optimization")
+ DEFTIMEVAR (TV_LIM , "loop invariant motion")
DEFTIMEVAR (TV_TREE_CH , "tree copy headers")
DEFTIMEVAR (TV_TREE_SSA_TO_NORMAL , "tree SSA to normal")
DEFTIMEVAR (TV_TREE_NRV , "tree NRV optimization")
Index: tree-dfa.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-dfa.c,v
retrieving revision 2.15
diff -c -3 -p -r2.15 tree-dfa.c
*** tree-dfa.c 25 Jun 2004 18:30:09 -0000 2.15
--- tree-dfa.c 8 Jul 2004 15:52:50 -0000
*************** compute_immediate_uses (int flags, bool
*** 178,184 ****
tree phi;
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
! compute_immediate_uses_for_phi (phi, calc_for);
for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
{
--- 178,197 ----
tree phi;
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
! {
! if (is_gimple_reg (PHI_RESULT (phi)))
! {
! if (!(flags & TDFA_USE_OPS))
! continue;
! }
! else
! {
! if (!(flags & TDFA_USE_VOPS))
! continue;
! }
!
! compute_immediate_uses_for_phi (phi, calc_for);
! }
for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
{
Index: tree-eh.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-eh.c,v
retrieving revision 2.8
diff -c -3 -p -r2.8 tree-eh.c
*** tree-eh.c 29 Jun 2004 06:59:34 -0000 2.8
--- tree-eh.c 8 Jul 2004 15:52:50 -0000
*************** tree_could_trap_p (tree expr)
*** 1702,1708 ****
bool honor_nans = false;
bool honor_snans = false;
bool fp_operation = false;
! tree t;
if (TREE_CODE_CLASS (code) == '<'
|| TREE_CODE_CLASS (code) == '1'
--- 1702,1708 ----
bool honor_nans = false;
bool honor_snans = false;
bool fp_operation = false;
! tree t, base, idx;
if (TREE_CODE_CLASS (code) == '<'
|| TREE_CODE_CLASS (code) == '1'
*************** tree_could_trap_p (tree expr)
*** 1719,1732 ****
switch (code)
{
- case ARRAY_REF:
- case ARRAY_RANGE_REF:
case COMPONENT_REF:
case REALPART_EXPR:
case IMAGPART_EXPR:
case BIT_FIELD_REF:
! t = get_base_address (expr);
! return !t || tree_could_trap_p (t);
case INDIRECT_REF:
return !TREE_THIS_NOTRAP (expr);
--- 1719,1742 ----
switch (code)
{
case COMPONENT_REF:
case REALPART_EXPR:
case IMAGPART_EXPR:
case BIT_FIELD_REF:
! t = TREE_OPERAND (expr, 0);
! return tree_could_trap_p (t);
!
! case ARRAY_REF:
! case ARRAY_RANGE_REF:
! base = TREE_OPERAND (expr, 0);
! idx = TREE_OPERAND (expr, 1);
! if (tree_could_trap_p (base))
! return true;
!
! if (TREE_CODE_CLASS (TREE_CODE (idx)) != 'c')
! return true;
!
! return !in_array_bounds_p (base, idx);
case INDIRECT_REF:
return !TREE_THIS_NOTRAP (expr);
Index: tree-flow.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-flow.h,v
retrieving revision 2.20
diff -c -3 -p -r2.20 tree-flow.h
*** tree-flow.h 8 Jul 2004 06:34:22 -0000 2.20
--- tree-flow.h 8 Jul 2004 15:52:50 -0000
*************** struct tree_ann_common_d GTY(())
*** 80,85 ****
--- 80,89 ----
/* Annotation type. */
enum tree_ann_type type;
+ /* Auxiliary info specific to a pass. At all times, this
+ should either point to valid data or be NULL. */
+ PTR GTY ((skip (""))) aux;
+
/* The value handle for this expression. Used by GVN-PRE. */
tree GTY((skip)) value_handle;
};
*************** extern void propagate_tree_value (tree *
*** 597,602 ****
--- 601,612 ----
extern void replace_exp (use_operand_p, tree);
extern bool may_propagate_copy (tree, tree);
+ /* In tree-ssa-loop-*.c */
+
+ void loop_commit_inserts (void);
+ bool for_each_index (tree *, bool (*) (tree, tree *, void *), void *);
+ void tree_ssa_lim (struct loops *);
+
/* In tree-flow-inline.h */
static inline int phi_arg_from_edge (tree, edge);
static inline bool is_call_clobbered (tree);
Index: tree-optimize.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-optimize.c,v
retrieving revision 2.26
diff -c -3 -p -r2.26 tree-optimize.c
*** tree-optimize.c 7 Jul 2004 03:19:55 -0000 2.26
--- tree-optimize.c 8 Jul 2004 15:52:50 -0000
*************** init_tree_optimization_passes (void)
*** 327,332 ****
--- 327,333 ----
p = &pass_loop.sub;
NEXT_PASS (pass_loop_init);
+ NEXT_PASS (pass_lim);
NEXT_PASS (pass_loop_done);
*p = NULL;
Index: tree-pass.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-pass.h,v
retrieving revision 2.4
diff -c -3 -p -r2.4 tree-pass.h
*** tree-pass.h 30 Jun 2004 21:28:59 -0000 2.4
--- tree-pass.h 8 Jul 2004 15:52:50 -0000
*************** extern struct tree_opt_pass pass_tail_re
*** 107,112 ****
--- 107,113 ----
extern struct tree_opt_pass pass_tail_calls;
extern struct tree_opt_pass pass_loop;
extern struct tree_opt_pass pass_loop_init;
+ extern struct tree_opt_pass pass_lim;
extern struct tree_opt_pass pass_loop_done;
extern struct tree_opt_pass pass_ch;
extern struct tree_opt_pass pass_ccp;
Index: tree-ssa-loop-im.c
===================================================================
RCS file: tree-ssa-loop-im.c
diff -N tree-ssa-loop-im.c
*** /dev/null 1 Jan 1970 00:00:00 -0000
--- tree-ssa-loop-im.c 8 Jul 2004 15:52:50 -0000
***************
*** 0 ****
--- 1,1217 ----
+ /* Loop invariant motion.
+ Copyright (C) 2003 Free Software Foundation, Inc.
+
+ This file is part of GCC.
+
+ GCC is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by the
+ Free Software Foundation; either version 2, or (at your option) any
+ later version.
+
+ GCC is distributed in the hope that it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with GCC; see the file COPYING. If not, write to the Free
+ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+ 02111-1307, USA. */
+
+ #include "config.h"
+ #include "system.h"
+ #include "coretypes.h"
+ #include "tm.h"
+ #include "tree.h"
+ #include "rtl.h"
+ #include "tm_p.h"
+ #include "hard-reg-set.h"
+ #include "basic-block.h"
+ #include "output.h"
+ #include "diagnostic.h"
+ #include "tree-flow.h"
+ #include "tree-dump.h"
+ #include "timevar.h"
+ #include "cfgloop.h"
+ #include "domwalk.h"
+ #include "params.h"
+ #include "tree-pass.h"
+ #include "flags.h"
+
+ /* A type for the list of statements that have to be moved in order to be able
+ to hoist an invariant computation. */
+
+ struct depend
+ {
+ tree stmt;
+ struct depend *next;
+ };
+
+ /* The possibilities of statement movement. */
+
+ enum move_pos
+ {
+ MOVE_IMPOSSIBLE, /* No movement -- side effect expression. */
+ MOVE_PRESERVE_EXECUTION, /* Must not cause the non-executed statement
+ become executed -- memory accesses, ... */
+ MOVE_POSSIBLE /* Unlimited movement. */
+ };
+
+ /* The auxiliary data kept for each statement. */
+
+ struct lim_aux_data
+ {
+ struct loop *max_loop; /* The outermost loop in that the statement
+ is invariant. */
+
+ struct loop *tgt_loop; /* The loop out of that we want to move the
+ invariant. */
+
+ struct loop *always_executed_in;
+ /* The outermost loop for that we are sure
+ the statement is executed if the loop
+ is entered. */
+
+ bool sm_done; /* True iff the store motion for a memory
+ reference in the statement has already
+ been executed. */
+
+ unsigned cost; /* Cost of the computation performed by the
+ statement. */
+
+ struct depend *depends; /* List of statements that must be also hoisted
+ out of the loop when this statement is
+ hoisted; i.e. those that define the operands
+ of the statement and are inside of the
+ MAX_LOOP loop. */
+ };
+
+ #define LIM_DATA(STMT) ((struct lim_aux_data *) (stmt_ann (STMT)->common.aux))
+
+ /* Description of a memory reference for store motion. */
+
+ struct mem_ref
+ {
+ tree *ref; /* The reference itself. */
+ tree stmt; /* The statement in that it occurs. */
+ struct mem_ref *next; /* Next use in the chain. */
+ };
+
+ /* Minimum cost of an expensive expression. */
+ #define LIM_EXPENSIVE ((unsigned) PARAM_VALUE (PARAM_LIM_EXPENSIVE))
+
+ /* The outermost loop for that execution of the header guarantees that the
+ block will be executed. */
+ #define ALWAYS_EXECUTED_IN(BB) ((struct loop *) (BB)->aux)
+
+ /* Maximum uid in the statement in the function. */
+
+ static unsigned max_uid;
+
+ /* Calls CBCK for each index in memory reference ADDR_P. There are two
+ situations handled:
+
+ Access to an array: ARRAY_REF (base, index). In this case we pass the pointer
+ to the index, the base if it is an array and DATA to the callback.
+
+ Pointer dereference: INDIRECT_REF (index). In this case we pass the pointer
+ to the index and DATA to the callback, and pass NULL_TREE instead of the
+ array base.
+
+ If the callback returns false, the whole search stops and false is returned.
+ Otherwise the function returns true after traversing through the whole
+ reference *ADDR_P. */
+
+ bool
+ for_each_index (tree *addr_p, bool (*cbck) (tree, tree *, void *), void *data)
+ {
+ tree *nxt;
+
+ for (; ; addr_p = nxt)
+ {
+ switch (TREE_CODE (*addr_p))
+ {
+ case SSA_NAME:
+ return cbck (NULL, addr_p, data);
+
+ case INDIRECT_REF:
+ nxt = &TREE_OPERAND (*addr_p, 0);
+ return cbck (NULL, nxt, data);
+
+ case BIT_FIELD_REF:
+ case COMPONENT_REF:
+ case VIEW_CONVERT_EXPR:
+ nxt = &TREE_OPERAND (*addr_p, 0);
+ break;
+
+ case ARRAY_REF:
+ case ARRAY_RANGE_REF:
+ nxt = &TREE_OPERAND (*addr_p, 0);
+ if (!cbck (*nxt, &TREE_OPERAND (*addr_p, 1), data))
+ return false;
+ break;
+
+ case VAR_DECL:
+ case PARM_DECL:
+ case STRING_CST:
+ case RESULT_DECL:
+ return true;
+
+ default:
+ abort ();
+ }
+ }
+ }
+
+ /* If it is possible to hoist the statement STMT unconditionally,
+ returns MOVE_POSSIBLE.
+ If it is possible to hoist the statement STMT, but we must avoid making
+ it executed if it would not be executed in the original program (e.g.
+ because it may trap), return MOVE_PRESERVE_EXECUTION.
+ Otherwise return MOVE_IMPOSSIBLE. */
+
+ static enum move_pos
+ movement_possibility (tree stmt)
+ {
+ tree lhs, rhs;
+
+ if (flag_unswitch_loops
+ && TREE_CODE (stmt) == COND_EXPR)
+ {
+ /* If we perform unswitching, force the operands of the invariant
+ condition to be moved out of the loop. */
+ get_stmt_operands (stmt);
+
+ return MOVE_POSSIBLE;
+ }
+
+ if (TREE_CODE (stmt) != MODIFY_EXPR)
+ return MOVE_IMPOSSIBLE;
+
+ if (stmt_ends_bb_p (stmt))
+ return MOVE_IMPOSSIBLE;
+
+ get_stmt_operands (stmt);
+
+ if (stmt_ann (stmt)->has_volatile_ops)
+ return MOVE_IMPOSSIBLE;
+
+ lhs = TREE_OPERAND (stmt, 0);
+ if (TREE_CODE (lhs) == SSA_NAME
+ && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
+ return MOVE_IMPOSSIBLE;
+
+ rhs = TREE_OPERAND (stmt, 1);
+
+ if (TREE_SIDE_EFFECTS (rhs))
+ return MOVE_IMPOSSIBLE;
+
+ if (TREE_CODE (lhs) != SSA_NAME
+ || tree_could_trap_p (rhs))
+ return MOVE_PRESERVE_EXECUTION;
+
+ return MOVE_POSSIBLE;
+ }
+
+ /* Suppose that operand DEF is used inside the LOOP. Returns the outermost
+ loop to that we could move the expresion using DEF if it did not have
+ other operands, i.e. the outermost loop enclosing LOOP in that the value
+ of DEF is invariant. */
+
+ static struct loop *
+ outermost_invariant_loop (tree def, struct loop *loop)
+ {
+ tree def_stmt;
+ basic_block def_bb;
+ struct loop *max_loop;
+
+ if (is_gimple_min_invariant (def))
+ return superloop_at_depth (loop, 1);
+
+ def_stmt = SSA_NAME_DEF_STMT (def);
+ def_bb = bb_for_stmt (def_stmt);
+ if (!def_bb)
+ return superloop_at_depth (loop, 1);
+
+ max_loop = find_common_loop (loop, def_bb->loop_father);
+
+ if (LIM_DATA (def_stmt) && LIM_DATA (def_stmt)->max_loop)
+ max_loop = find_common_loop (max_loop,
+ LIM_DATA (def_stmt)->max_loop->outer);
+ if (max_loop == loop)
+ return NULL;
+ max_loop = superloop_at_depth (loop, max_loop->depth + 1);
+
+ return max_loop;
+ }
+
+ /* DATA is a structure containing information associated with a statement
+ inside LOOP. DEF is one of the operands of this statement.
+
+ Find the outermost loop enclosing LOOP in that value of DEF is invariant
+ and record this in DATA->max_loop field. If DEF itself is defined inside
+ this loop as well (i.e. we need to hoist it out of the loop if we want
+ to hoist the statement represented by DATA), record the statement in that
+ DEF is defined to the DATA->depends list. Additionally if ADD_COST is true,
+ add the cost of the computation of DEF to the DATA->cost.
+
+ If DEF is not invariant in LOOP, return false. Otherwise return TRUE. */
+
+ static bool
+ add_dependency (tree def, struct lim_aux_data *data, struct loop *loop,
+ bool add_cost)
+ {
+ tree def_stmt = SSA_NAME_DEF_STMT (def);
+ basic_block def_bb = bb_for_stmt (def_stmt);
+ struct loop *max_loop;
+ struct depend *dep;
+
+ if (!def_bb)
+ return true;
+
+ max_loop = outermost_invariant_loop (def, loop);
+ if (!max_loop)
+ return false;
+
+ if (flow_loop_nested_p (data->max_loop, max_loop))
+ data->max_loop = max_loop;
+
+ if (!LIM_DATA (def_stmt))
+ return true;
+
+ if (add_cost
+ /* Only add the cost if the statement defining DEF is inside LOOP,
+ i.e. if it is likely that by moving the invariants dependent
+ on it, we will be able to avoid creating a new register for
+ it (since it will be only used in these dependent invariants). */
+ && def_bb->loop_father == loop)
+ data->cost += LIM_DATA (def_stmt)->cost;
+
+ dep = xmalloc (sizeof (struct depend));
+ dep->stmt = def_stmt;
+ dep->next = data->depends;
+ data->depends = dep;
+
+ return true;
+ }
+
+ /* Returns an estimate for a cost of statement STMT. TODO -- the values here
+ are just ad-hoc constants. The estimates should be based on target-specific
+ values. */
+
+ static unsigned
+ stmt_cost (tree stmt)
+ {
+ tree lhs, rhs;
+ unsigned cost = 1;
+
+ /* Always try to create possibilities for unswitching. */
+ if (TREE_CODE (stmt) == COND_EXPR)
+ return LIM_EXPENSIVE;
+
+ lhs = TREE_OPERAND (stmt, 0);
+ rhs = TREE_OPERAND (stmt, 1);
+
+ /* Hoisting memory references out should almost surely be a win. */
+ if (!is_gimple_variable (lhs))
+ cost += 20;
+ if (is_gimple_addr_expr_arg (rhs) && !is_gimple_variable (rhs))
+ cost += 20;
+
+ switch (TREE_CODE (rhs))
+ {
+ case CALL_EXPR:
+ /* We should be hoisting calls if possible. */
+
+ /* Unless the call is a builtin_constant_p; this always folds to a
+ constant, so moving it is useless. */
+ rhs = get_callee_fndecl (rhs);
+ if (DECL_BUILT_IN (rhs)
+ && DECL_FUNCTION_CODE (rhs) == BUILT_IN_CONSTANT_P)
+ return 0;
+
+ cost += 20;
+ break;
+
+ case MULT_EXPR:
+ case TRUNC_DIV_EXPR:
+ case CEIL_DIV_EXPR:
+ case FLOOR_DIV_EXPR:
+ case ROUND_DIV_EXPR:
+ case EXACT_DIV_EXPR:
+ case CEIL_MOD_EXPR:
+ case FLOOR_MOD_EXPR:
+ case ROUND_MOD_EXPR:
+ case TRUNC_MOD_EXPR:
+ /* Division and multiplication are usually expensive. */
+ cost += 20;
+ break;
+
+ default:
+ break;
+ }
+
+ return cost;
+ }
+
+ /* Determine the outermost loop to that it is possible to hoist a statement
+ STMT and store it to LIM_DATA (STMT)->max_loop. To do this we determine
+ the outermost loop in that the value computed by STMT is invariant.
+ If MUST_PRESERVE_EXEC is true, additionally choose such a loop that
+ we preserve the fact whether STMT is executed. It also fills other related
+ information to LIM_DATA (STMT).
+
+ The function returns false if STMT cannot be hoisted outside of the loop it
+ is defined in, and true otherwise. */
+
+ static bool
+ determine_max_movement (tree stmt, bool must_preserve_exec)
+ {
+ basic_block bb = bb_for_stmt (stmt);
+ struct loop *loop = bb->loop_father;
+ struct loop *level;
+ struct lim_aux_data *lim_data = LIM_DATA (stmt);
+ use_optype uses;
+ vuse_optype vuses;
+ v_may_def_optype v_may_defs;
+ stmt_ann_t ann = stmt_ann (stmt);
+ unsigned i;
+
+ if (must_preserve_exec)
+ level = ALWAYS_EXECUTED_IN (bb);
+ else
+ level = superloop_at_depth (loop, 1);
+ lim_data->max_loop = level;
+
+ uses = USE_OPS (ann);
+ for (i = 0; i < NUM_USES (uses); i++)
+ if (!add_dependency (USE_OP (uses, i), lim_data, loop, true))
+ return false;
+
+ vuses = VUSE_OPS (ann);
+ for (i = 0; i < NUM_VUSES (vuses); i++)
+ if (!add_dependency (VUSE_OP (vuses, i), lim_data, loop, false))
+ return false;
+
+ v_may_defs = V_MAY_DEF_OPS (ann);
+ for (i = 0; i < NUM_V_MAY_DEFS (v_may_defs); i++)
+ if (!add_dependency (V_MAY_DEF_OP (v_may_defs, i), lim_data, loop, false))
+ return false;
+
+ lim_data->cost += stmt_cost (stmt);
+
+ return true;
+ }
+
+ /* Suppose that some statement in ORIG_LOOP is hoisted to the loop LEVEL,
+ and that one of the operands of this statement is computed by STMT.
+ Ensure that STMT (together with all the statements that define its
+ operands) is hoisted at least out of the loop LEVEL. */
+
+ static void
+ set_level (tree stmt, struct loop *orig_loop, struct loop *level)
+ {
+ struct loop *stmt_loop = bb_for_stmt (stmt)->loop_father;
+ struct depend *dep;
+
+ stmt_loop = find_common_loop (orig_loop, stmt_loop);
+ if (LIM_DATA (stmt) && LIM_DATA (stmt)->tgt_loop)
+ stmt_loop = find_common_loop (stmt_loop,
+ LIM_DATA (stmt)->tgt_loop->outer);
+ if (flow_loop_nested_p (stmt_loop, level))
+ return;
+
+ if (!LIM_DATA (stmt))
+ abort ();
+
+ if (level != LIM_DATA (stmt)->max_loop
+ && !flow_loop_nested_p (LIM_DATA (stmt)->max_loop, level))
+ abort ();
+
+ LIM_DATA (stmt)->tgt_loop = level;
+ for (dep = LIM_DATA (stmt)->depends; dep; dep = dep->next)
+ set_level (dep->stmt, orig_loop, level);
+ }
+
+ /* Determines an outermost loop from that we want to hoist the statement STMT.
+ For now we chose the outermost possible loop. TODO -- use profiling
+ information to set it more sanely. */
+
+ static void
+ set_profitable_level (tree stmt)
+ {
+ set_level (stmt, bb_for_stmt (stmt)->loop_father, LIM_DATA (stmt)->max_loop);
+ }
+
+ /* Returns true if STMT is not a pure call. */
+
+ static bool
+ nonpure_call_p (tree stmt)
+ {
+ tree call = get_call_expr_in (stmt);
+
+ if (!call)
+ return false;
+
+ return TREE_SIDE_EFFECTS (call) != 0;
+ }
+
+ /* Releases the memory occupied by DATA. */
+
+ static void
+ free_lim_aux_data (struct lim_aux_data *data)
+ {
+ struct depend *dep, *next;
+
+ for (dep = data->depends; dep; dep = next)
+ {
+ next = dep->next;
+ free (dep);
+ }
+ free (data);
+ }
+
+ /* Determine the outermost loops in that statements in basic block BB are
+ invariant, and record them to the LIM_DATA associated with the statements.
+ Callback for walk_dominator_tree. */
+
+ static void
+ determine_invariantness_stmt (struct dom_walk_data *dw_data ATTRIBUTE_UNUSED,
+ basic_block bb)
+ {
+ enum move_pos pos;
+ block_stmt_iterator bsi;
+ tree stmt;
+ bool maybe_never = ALWAYS_EXECUTED_IN (bb) == NULL;
+ struct loop *outermost = ALWAYS_EXECUTED_IN (bb);
+
+ if (!bb->loop_father->outer)
+ return;
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "Basic block %d (loop %d -- depth %d):\n\n",
+ bb->index, bb->loop_father->num, bb->loop_father->depth);
+
+ for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
+ {
+ stmt = bsi_stmt (bsi);
+
+ pos = movement_possibility (stmt);
+ if (pos == MOVE_IMPOSSIBLE)
+ {
+ if (nonpure_call_p (stmt))
+ {
+ maybe_never = true;
+ outermost = NULL;
+ }
+ continue;
+ }
+
+ stmt_ann (stmt)->common.aux = xcalloc (1, sizeof (struct lim_aux_data));
+ LIM_DATA (stmt)->always_executed_in = outermost;
+
+ if (maybe_never && pos == MOVE_PRESERVE_EXECUTION)
+ continue;
+
+ if (!determine_max_movement (stmt, pos == MOVE_PRESERVE_EXECUTION))
+ {
+ LIM_DATA (stmt)->max_loop = NULL;
+ continue;
+ }
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ print_generic_stmt_indented (dump_file, stmt, 0, 2);
+ fprintf (dump_file, " invariant up to level %d, cost %d.\n\n",
+ LIM_DATA (stmt)->max_loop->depth,
+ LIM_DATA (stmt)->cost);
+ }
+
+ if (LIM_DATA (stmt)->cost >= LIM_EXPENSIVE)
+ set_profitable_level (stmt);
+ }
+ }
+
+ /* For each statement determines the outermost loop in that it is invariant,
+ statements on whose motion it depends and the cost of the computation.
+ This information is stored to the LIM_DATA structure associated with
+ each statement. */
+
+ static void
+ determine_invariantness (void)
+ {
+ struct dom_walk_data walk_data;
+
+ memset (&walk_data, 0, sizeof (struct dom_walk_data));
+ walk_data.before_dom_children_before_stmts = determine_invariantness_stmt;
+
+ init_walk_dominator_tree (&walk_data);
+ walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR);
+ fini_walk_dominator_tree (&walk_data);
+ }
+
+ /* Commits edge insertions and updates loop structures. */
+
+ void
+ loop_commit_inserts (void)
+ {
+ unsigned old_last_basic_block, i;
+ basic_block bb;
+
+ old_last_basic_block = last_basic_block;
+ bsi_commit_edge_inserts (NULL);
+ for (i = old_last_basic_block; i < (unsigned) last_basic_block; i++)
+ {
+ bb = BASIC_BLOCK (i);
+ add_bb_to_loop (bb,
+ find_common_loop (bb->succ->dest->loop_father,
+ bb->pred->src->loop_father));
+ }
+ }
+
+ /* Hoist the statements in basic block BB out of the loops prescribed by
+ data stored in LIM_DATA structres associated with each statement. Callback
+ for walk_dominator_tree. */
+
+ static void
+ move_computations_stmt (struct dom_walk_data *dw_data ATTRIBUTE_UNUSED,
+ basic_block bb)
+ {
+ struct loop *level;
+ block_stmt_iterator bsi;
+ tree stmt;
+ unsigned cost = 0;
+
+ if (!bb->loop_father->outer)
+ return;
+
+ for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
+ {
+ stmt = bsi_stmt (bsi);
+
+ if (!LIM_DATA (stmt))
+ {
+ bsi_next (&bsi);
+ continue;
+ }
+
+ cost = LIM_DATA (stmt)->cost;
+ level = LIM_DATA (stmt)->tgt_loop;
+ free_lim_aux_data (LIM_DATA (stmt));
+ stmt_ann (stmt)->common.aux = NULL;
+
+ if (!level)
+ {
+ bsi_next (&bsi);
+ continue;
+ }
+
+ /* We do not really want to move conditionals out of the loop; we just
+ placed it here to force its operands to be moved if necessary. */
+ if (TREE_CODE (stmt) == COND_EXPR)
+ continue;
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Moving statement\n");
+ print_generic_stmt (dump_file, stmt, 0);
+ fprintf (dump_file, "(cost %u) out of loop %d.\n\n",
+ cost, level->num);
+ }
+ bsi_insert_on_edge (loop_preheader_edge (level), stmt);
+ bsi_remove (&bsi);
+ }
+ }
+
+ /* Hoist the statements out of the loops prescribed by data stored in
+ LIM_DATA structres associated with each statement.*/
+
+ static void
+ move_computations (void)
+ {
+ struct dom_walk_data walk_data;
+
+ memset (&walk_data, 0, sizeof (struct dom_walk_data));
+ walk_data.before_dom_children_before_stmts = move_computations_stmt;
+
+ init_walk_dominator_tree (&walk_data);
+ walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR);
+ fini_walk_dominator_tree (&walk_data);
+
+ loop_commit_inserts ();
+ rewrite_into_ssa (false);
+ bitmap_clear (vars_to_rename);
+ }
+
+ /* Checks whether the statement defining variable *INDEX can be hoisted
+ out of the loop passed in DATA. Callback for for_each_index. */
+
+ static bool
+ may_move_till (tree base ATTRIBUTE_UNUSED, tree *index, void *data)
+ {
+ struct loop *loop = data, *max_loop;
+
+ if (TREE_CODE (*index) != SSA_NAME)
+ return true;
+
+ max_loop = outermost_invariant_loop (*index, loop);
+
+ if (!max_loop)
+ return false;
+
+ if (loop == max_loop
+ || flow_loop_nested_p (max_loop, loop))
+ return true;
+
+ return false;
+ }
+
+ /* Forces statement defining variable *INDEX to be moved out of the
+ loop passed in DATA. Callback for for_each_index. */
+
+ static bool
+ force_move_till (tree base ATTRIBUTE_UNUSED, tree *index, void *data)
+ {
+ tree stmt;
+
+ if (TREE_CODE (*index) != SSA_NAME)
+ return true;
+
+ stmt = SSA_NAME_DEF_STMT (*index);
+ if (IS_EMPTY_STMT (stmt))
+ return true;
+
+ set_level (stmt, bb_for_stmt (stmt)->loop_father, data);
+
+ return true;
+ }
+
+ /* Records memory reference *REF (that occurs in statement STMT)
+ to the list MEM_REFS. */
+
+ static void
+ record_mem_ref (struct mem_ref **mem_refs, tree stmt, tree *ref)
+ {
+ struct mem_ref *aref = xmalloc (sizeof (struct mem_ref));
+
+ aref->stmt = stmt;
+ aref->ref = ref;
+
+ aref->next = *mem_refs;
+ *mem_refs = aref;
+ }
+
+ /* Releases list of memory references MEM_REFS. */
+
+ static void
+ free_mem_refs (struct mem_ref *mem_refs)
+ {
+ struct mem_ref *act;
+
+ while (mem_refs)
+ {
+ act = mem_refs;
+ mem_refs = mem_refs->next;
+ free (act);
+ }
+ }
+
+ /* If VAR is defined in LOOP and the statement it is defined in does not belong
+ to the set SEEN, add the statement to QUEUE of length IN_QUEUE and
+ to the set SEEN. */
+
+ static void
+ maybe_queue_var (tree var, struct loop *loop,
+ sbitmap seen, tree *queue, unsigned *in_queue)
+ {
+ tree stmt = SSA_NAME_DEF_STMT (var);
+ basic_block def_bb = bb_for_stmt (stmt);
+
+ if (!def_bb
+ || !flow_bb_inside_loop_p (loop, def_bb)
+ || TEST_BIT (seen, stmt_ann (stmt)->uid))
+ return;
+
+ SET_BIT (seen, stmt_ann (stmt)->uid);
+ queue[(*in_queue)++] = stmt;
+ }
+
+ /* Determine whether all memory references inside the LOOP that correspond
+ to virtual ssa names defined in statement STMT are equal.
+ If so, store the list of the references to MEM_REFS, and return one
+ of them. Otherwise store NULL to MEM_REFS and return NULL_TREE. */
+
+ static tree
+ single_reachable_address (struct loop *loop, tree stmt,
+ struct mem_ref **mem_refs)
+ {
+ tree *queue = xmalloc (sizeof (tree) * max_uid);
+ sbitmap seen = sbitmap_alloc (max_uid);
+ tree common_ref = NULL, *aref;
+ unsigned in_queue = 1;
+ dataflow_t df;
+ unsigned i, n;
+ v_may_def_optype v_may_defs;
+ vuse_optype vuses;
+
+ sbitmap_zero (seen);
+
+ *mem_refs = NULL;
+
+ queue[0] = stmt;
+ SET_BIT (seen, stmt_ann (stmt)->uid);
+
+ while (in_queue)
+ {
+ stmt = queue[--in_queue];
+
+ if (LIM_DATA (stmt)
+ && LIM_DATA (stmt)->sm_done)
+ goto fail;
+
+ switch (TREE_CODE (stmt))
+ {
+ case MODIFY_EXPR:
+ aref = &TREE_OPERAND (stmt, 0);
+ if (is_gimple_reg (*aref)
+ || !is_gimple_lvalue (*aref))
+ aref = &TREE_OPERAND (stmt, 1);
+ if (is_gimple_reg (*aref)
+ || !is_gimple_lvalue (*aref)
+ || (common_ref && !operand_equal_p (*aref, common_ref, 0)))
+ goto fail;
+ common_ref = *aref;
+
+ record_mem_ref (mem_refs, stmt, aref);
+
+ /* Traverse also definitions of the VUSES (there may be other
+ distinct from the one we used to get to this statement). */
+ v_may_defs = STMT_V_MAY_DEF_OPS (stmt);
+ for (i = 0; i < NUM_V_MAY_DEFS (v_may_defs); i++)
+ maybe_queue_var (V_MAY_DEF_OP (v_may_defs, i), loop,
+ seen, queue, &in_queue);
+
+ vuses = STMT_VUSE_OPS (stmt);
+ for (i = 0; i < NUM_VUSES (vuses); i++)
+ maybe_queue_var (VUSE_OP (vuses, i), loop,
+ seen, queue, &in_queue);
+ break;
+
+ case PHI_NODE:
+ for (i = 0; i < (unsigned) PHI_NUM_ARGS (stmt); i++)
+ maybe_queue_var (PHI_ARG_DEF (stmt, i), loop,
+ seen, queue, &in_queue);
+ break;
+
+ default:
+ goto fail;
+ }
+
+ /* Find uses of virtual names. */
+ df = get_immediate_uses (stmt);
+ n = num_immediate_uses (df);
+
+ for (i = 0; i < n; i++)
+ {
+ stmt = immediate_use (df, i);
+
+ if (!flow_bb_inside_loop_p (loop, bb_for_stmt (stmt)))
+ continue;
+
+ if (TEST_BIT (seen, stmt_ann (stmt)->uid))
+ continue;
+ SET_BIT (seen, stmt_ann (stmt)->uid);
+
+ queue[in_queue++] = stmt;
+ }
+ }
+
+ free (queue);
+ sbitmap_free (seen);
+
+ return common_ref;
+
+ fail:
+ free_mem_refs (*mem_refs);
+ *mem_refs = NULL;
+ free (queue);
+ sbitmap_free (seen);
+
+ return NULL;
+ }
+
+ /* Rewrites memory references in list MEM_REFS by variable TMP_VAR. */
+
+ static void
+ rewrite_mem_refs (tree tmp_var, struct mem_ref *mem_refs)
+ {
+ v_may_def_optype v_may_defs;
+ v_must_def_optype v_must_defs;
+ vuse_optype vuses;
+ unsigned i;
+ tree var;
+
+ for (; mem_refs; mem_refs = mem_refs->next)
+ {
+ v_may_defs = STMT_V_MAY_DEF_OPS (mem_refs->stmt);
+ for (i = 0; i < NUM_V_MAY_DEFS (v_may_defs); i++)
+ {
+ var = SSA_NAME_VAR (V_MAY_DEF_RESULT (v_may_defs, i));
+ bitmap_set_bit (vars_to_rename, var_ann (var)->uid);
+ }
+
+ v_must_defs = STMT_V_MUST_DEF_OPS (mem_refs->stmt);
+ for (i = 0; i < NUM_V_MUST_DEFS (v_must_defs); i++)
+ {
+ var = SSA_NAME_VAR (V_MUST_DEF_OP (v_must_defs, i));
+ bitmap_set_bit (vars_to_rename, var_ann (var)->uid);
+ }
+
+ vuses = STMT_VUSE_OPS (mem_refs->stmt);
+ for (i = 0; i < NUM_VUSES (vuses); i++)
+ {
+ var = SSA_NAME_VAR (VUSE_OP (vuses, i));
+ bitmap_set_bit (vars_to_rename, var_ann (var)->uid);
+ }
+
+ *mem_refs->ref = tmp_var;
+ modify_stmt (mem_refs->stmt);
+ }
+ }
+
+ /* Records request for store motion of memory reference REF from LOOP.
+ MEM_REFS is the list of occurences of the reference REF inside LOOP;
+ these references are rewritten by a new temporary variable.
+ Exits from the LOOP are stored in EXITS, there are N_EXITS of them.
+ The initialization of the temporary variable is put to the preheader
+ of the loop, and assignments to the reference from the temporary variable
+ are emitted to exits. */
+
+ static void
+ schedule_sm (struct loop *loop, edge *exits, unsigned n_exits, tree ref,
+ struct mem_ref *mem_refs)
+ {
+ struct mem_ref *aref;
+ tree tmp_var;
+ unsigned i;
+ tree load, store;
+
+ tmp_var = make_rename_temp (TREE_TYPE (ref), "lsm_tmp");
+
+ for_each_index (&ref, force_move_till, loop);
+
+ rewrite_mem_refs (tmp_var, mem_refs);
+ for (aref = mem_refs; aref; aref = aref->next)
+ if (LIM_DATA (aref->stmt))
+ LIM_DATA (aref->stmt)->sm_done = true;
+
+ /* Emit the load & stores. */
+ load = build (MODIFY_EXPR, void_type_node, tmp_var, ref);
+ modify_stmt (load);
+ stmt_ann (load)->common.aux = xcalloc (1, sizeof (struct lim_aux_data));
+ LIM_DATA (load)->max_loop = loop;
+ LIM_DATA (load)->tgt_loop = loop;
+
+ /* Put this into the latch, so that we are sure it will be processed after
+ all dependencies. */
+ bsi_insert_on_edge (loop_latch_edge (loop), load);
+
+ for (i = 0; i < n_exits; i++)
+ {
+ store = build (MODIFY_EXPR, void_type_node,
+ unshare_expr (ref), tmp_var);
+ bsi_insert_on_edge (exits[i], store);
+ }
+ }
+
+ /* Determine whether all memory references inside LOOP corresponding to the
+ virtual ssa name REG are equal to each other, and whether the address of
+ this common reference can be hoisted outside of the loop. If this is true,
+ prepare the statements that load the value of the memory reference to a
+ temporary variable in the loop preheader, store it back on the loop exits,
+ and replace all the references inside LOOP by this temporary variable.
+ LOOP has N_EXITS stored in EXITS. */
+
+ static void
+ determine_lsm_reg (struct loop *loop, edge *exits, unsigned n_exits, tree reg)
+ {
+ tree ref;
+ struct mem_ref *mem_refs, *aref;
+ struct loop *must_exec;
+
+ if (is_gimple_reg (reg))
+ return;
+
+ ref = single_reachable_address (loop, SSA_NAME_DEF_STMT (reg), &mem_refs);
+ if (!ref)
+ return;
+
+ if (!for_each_index (&ref, may_move_till, loop))
+ {
+ free_mem_refs (mem_refs);
+ return;
+ }
+
+ if (tree_could_trap_p (ref))
+ {
+ /* If the memory access is unsafe (i.e. it might trap), ensure that some
+ of the statements in that it occurs is always executed when the loop
+ is entered. This way we know that by moving the load from the
+ reference out of the loop we will not cause the error that would not
+ occur otherwise.
+
+ TODO -- in fact we would like to check for anticipability of the
+ reference, i.e. that on each path from loop entry to loop exit at
+ least one of the statements containing the memory reference is
+ executed. */
+
+ for (aref = mem_refs; aref; aref = aref->next)
+ {
+ if (!LIM_DATA (aref->stmt))
+ continue;
+
+ must_exec = LIM_DATA (aref->stmt)->always_executed_in;
+ if (!must_exec)
+ continue;
+
+ if (must_exec == loop
+ || flow_loop_nested_p (must_exec, loop))
+ break;
+ }
+
+ if (!aref)
+ {
+ free_mem_refs (mem_refs);
+ return;
+ }
+ }
+
+ schedule_sm (loop, exits, n_exits, ref, mem_refs);
+ free_mem_refs (mem_refs);
+ }
+
+ /* Checks whether LOOP (with N_EXITS exits stored in EXITS array) is suitable
+ for a store motion optimization (i.e. whether we can insert statement
+ on its exits). */
+
+ static bool
+ loop_suitable_for_sm (struct loop *loop ATTRIBUTE_UNUSED, edge *exits,
+ unsigned n_exits)
+ {
+ unsigned i;
+
+ for (i = 0; i < n_exits; i++)
+ if (exits[i]->flags & EDGE_ABNORMAL)
+ return false;
+
+ return true;
+ }
+
+ /* Try to perform store motion for all memory references modified inside
+ LOOP. */
+
+ static void
+ determine_lsm_loop (struct loop *loop)
+ {
+ tree phi;
+ unsigned n_exits;
+ edge *exits = get_loop_exit_edges (loop, &n_exits);
+
+ if (!loop_suitable_for_sm (loop, exits, n_exits))
+ {
+ free (exits);
+ return;
+ }
+
+ for (phi = phi_nodes (loop->header); phi; phi = TREE_CHAIN (phi))
+ determine_lsm_reg (loop, exits, n_exits, PHI_RESULT (phi));
+
+ free (exits);
+ }
+
+ /* Try to perform store motion for all memory references modified inside
+ any of LOOPS. */
+
+ static void
+ determine_lsm (struct loops *loops)
+ {
+ struct loop *loop;
+ basic_block bb;
+
+ /* Create a UID for each statement in the function. Ordering of the
+ UIDs is not important for this pass. */
+ max_uid = 0;
+ FOR_EACH_BB (bb)
+ {
+ block_stmt_iterator bsi;
+ tree phi;
+
+ for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
+ stmt_ann (bsi_stmt (bsi))->uid = max_uid++;
+
+ for (phi = phi_nodes (bb); phi; phi = TREE_CHAIN (phi))
+ stmt_ann (phi)->uid = max_uid++;
+ }
+
+ compute_immediate_uses (TDFA_USE_VOPS, NULL);
+
+ /* Pass the loops from the outermost. For each virtual operand loop phi node
+ check whether all the references inside the loop correspond to a single
+ address, and if so, move them. */
+
+ loop = loops->tree_root->inner;
+ while (1)
+ {
+ determine_lsm_loop (loop);
+
+ if (loop->inner)
+ {
+ loop = loop->inner;
+ continue;
+ }
+ while (!loop->next)
+ {
+ loop = loop->outer;
+ if (loop == loops->tree_root)
+ {
+ free_df ();
+ loop_commit_inserts ();
+ return;
+ }
+ }
+ loop = loop->next;
+ }
+ }
+
+ /* Fills ALWAYS_EXECUTED_IN information for basic blocks of LOOP, i.e.
+ for each such basic block bb records the outermost loop for that execution
+ of its header implies execution of bb. CONTAINS_CALL is the bitmap of
+ blocks that contain a nonpure call. */
+
+ static void
+ fill_always_executed_in (struct loop *loop, sbitmap contains_call)
+ {
+ basic_block bb = NULL, *bbs, last = NULL;
+ unsigned i;
+ edge e;
+ struct loop *inn_loop = loop;
+
+ if (!loop->header->aux)
+ {
+ bbs = get_loop_body_in_dom_order (loop);
+
+ for (i = 0; i < loop->num_nodes; i++)
+ {
+ bb = bbs[i];
+
+ if (dominated_by_p (CDI_DOMINATORS, loop->latch, bb))
+ last = bb;
+
+ if (TEST_BIT (contains_call, bb->index))
+ break;
+
+ for (e = bb->succ; e; e = e->succ_next)
+ if (!flow_bb_inside_loop_p (loop, e->dest))
+ break;
+ if (e)
+ break;
+
+ /* A loop might be infinite (TODO use simple loop analysis
+ to disprove this if possible). */
+ if (bb->flags & BB_IRREDUCIBLE_LOOP)
+ break;
+
+ if (!flow_bb_inside_loop_p (inn_loop, bb))
+ break;
+
+ if (bb->loop_father->header == bb)
+ {
+ if (!dominated_by_p (CDI_DOMINATORS, loop->latch, bb))
+ break;
+
+ /* In a loop that is always entered we may proceed anyway.
+ But record that we entered it and stop once we leave it. */
+ inn_loop = bb->loop_father;
+ }
+ }
+
+ while (1)
+ {
+ last->aux = loop;
+ if (last == loop->header)
+ break;
+ last = get_immediate_dominator (CDI_DOMINATORS, last);
+ }
+
+ free (bbs);
+ }
+
+ for (loop = loop->inner; loop; loop = loop->next)
+ fill_always_executed_in (loop, contains_call);
+ }
+
+ /* Compute the global information needed by the loop invariant motion pass.
+ LOOPS is the loop tree. */
+
+ static void
+ tree_ssa_lim_initialize (struct loops *loops)
+ {
+ sbitmap contains_call = sbitmap_alloc (last_basic_block);
+ block_stmt_iterator bsi;
+ struct loop *loop;
+ basic_block bb;
+
+ sbitmap_zero (contains_call);
+ FOR_EACH_BB (bb)
+ {
+ for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
+ {
+ if (nonpure_call_p (bsi_stmt (bsi)))
+ break;
+ }
+
+ if (!bsi_end_p (bsi))
+ SET_BIT (contains_call, bb->index);
+ }
+
+ for (loop = loops->tree_root->inner; loop; loop = loop->next)
+ fill_always_executed_in (loop, contains_call);
+
+ sbitmap_free (contains_call);
+ }
+
+ /* Cleans up after the invariant motion pass. */
+
+ static void
+ tree_ssa_lim_finalize (void)
+ {
+ basic_block bb;
+
+ FOR_EACH_BB (bb)
+ {
+ bb->aux = NULL;
+ }
+ }
+
+ /* Moves invariants from LOOPS. Only "expensive" invariants are moved out --
+ i.e. those that are likely to be win regardless of the register pressure. */
+
+ void
+ tree_ssa_lim (struct loops *loops)
+ {
+ tree_ssa_lim_initialize (loops);
+
+ /* For each statement determine the outermost loop in that it is
+ invariant and cost for computing the invariant. */
+ determine_invariantness ();
+
+ /* For each memory reference determine whether it is possible to hoist it
+ out of the loop. Force the necessary invariants to be moved out of the
+ loops as well. */
+ determine_lsm (loops);
+
+ /* Move the expressions that are expensive enough. */
+ move_computations ();
+
+ tree_ssa_lim_finalize ();
+ }
Index: tree-ssa-loop.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-ssa-loop.c,v
retrieving revision 2.7
diff -c -3 -p -r2.7 tree-ssa-loop.c
*** tree-ssa-loop.c 30 Jun 2004 21:28:59 -0000 2.7
--- tree-ssa-loop.c 8 Jul 2004 15:52:50 -0000
*************** struct tree_opt_pass pass_loop_init =
*** 111,116 ****
--- 111,149 ----
0 /* todo_flags_finish */
};
+ /* Loop invariant motion pass. */
+
+ static void
+ tree_ssa_loop_im (void)
+ {
+ if (!current_loops)
+ return;
+
+ tree_ssa_lim (current_loops);
+ }
+
+ static bool
+ gate_tree_ssa_loop_im (void)
+ {
+ return flag_tree_lim != 0;
+ }
+
+ struct tree_opt_pass pass_lim =
+ {
+ "lim", /* name */
+ gate_tree_ssa_loop_im, /* gate */
+ tree_ssa_loop_im, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_LIM, /* tv_id */
+ PROP_cfg, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_dump_func /* todo_flags_finish */
+ };
+
/* Loop optimizer finalization. */
static void
Index: tree.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree.c,v
retrieving revision 1.392
diff -c -3 -p -r1.392 tree.c
*** tree.c 8 Jul 2004 08:44:09 -0000 1.392
--- tree.c 8 Jul 2004 15:52:51 -0000
*************** build_empty_stmt (void)
*** 5662,5667 ****
--- 5662,5697 ----
}
+ /* Returns true if it is possible to prove that IDX is inside bounds of
+ * ARRAY. */
+
+ bool
+ in_array_bounds_p (tree array, tree idx)
+ {
+ tree dom = TYPE_DOMAIN (TREE_TYPE (array));
+ tree min, max;
+
+ if (TREE_CODE (idx) != INTEGER_CST)
+ return false;
+
+ if (!dom)
+ return false;
+
+ min = TYPE_MIN_VALUE (dom);
+ max = TYPE_MAX_VALUE (dom);
+ if (!min
+ || !max
+ || TREE_CODE (min) != INTEGER_CST
+ || TREE_CODE (max) != INTEGER_CST)
+ return false;
+
+ if (tree_int_cst_lt (idx, min)
+ || tree_int_cst_lt (max, idx))
+ return false;
+
+ return true;
+ }
+
/* Return true if T (assumed to be a DECL) must be assigned a memory
location. */
Index: tree.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree.h,v
retrieving revision 1.547
diff -c -3 -p -r1.547 tree.h
*** tree.h 8 Jul 2004 08:44:10 -0000 1.547
--- tree.h 8 Jul 2004 15:52:51 -0000
*************** extern tree build_method_type (tree, tre
*** 2722,2727 ****
--- 2722,2728 ----
extern tree build_offset_type (tree, tree);
extern tree build_complex_type (tree);
extern tree array_type_nelts (tree);
+ extern bool in_array_bounds_p (tree, tree);
extern tree value_member (tree, tree);
extern tree purpose_member (tree, tree);
Index: doc/invoke.texi
===================================================================
RCS file: /cvs/gcc/gcc/gcc/doc/invoke.texi,v
retrieving revision 1.480
diff -c -3 -p -r1.480 invoke.texi
*** doc/invoke.texi 7 Jul 2004 19:24:57 -0000 1.480
--- doc/invoke.texi 8 Jul 2004 15:52:51 -0000
*************** in the following sections.
*** 313,318 ****
--- 313,319 ----
-funroll-all-loops -funroll-loops -fpeel-loops @gol
-funswitch-loops -fold-unroll-loops -fold-unroll-all-loops @gol
-ftree-pre -ftree-ccp -ftree-dce -ftree-loop-optimize @gol
+ -ftree-lim @gol
-ftree-dominator-opts -ftree-dse -ftree-copyrename @gol
-ftree-ch -ftree-sra -ftree-ter -ftree-lrs -ftree-fre @gol
--param @var{name}=@var{value}
*************** usually increases code size.
*** 4401,4406 ****
--- 4402,4415 ----
Perform loop optimizations on trees. This flag is enabled by default at -O
and higher.
+ @item -ftree-lim
+ Perform loop invariant motion on trees. This pass moves only invartiants that
+ would be hard to handle on rtl level (function calls, operations that expand to
+ nontrivial sequences of insns). With @option{-funswitch-loops} it also moves
+ operands of conditions that are invariant out of the loop, so that we can use
+ just trivial invariantness analysis in loop unswitching. The pass also includes
+ store motion.
+
@item -ftree-sra
Perform scalar replacement of aggregates. This pass replaces structure
references with scalars to prevent committing structures to memory too
*************** The maximum number of insns of an unswit
*** 5174,5179 ****
--- 5183,5191 ----
@item max-unswitch-level
The maximum number of branches unswitched in a single loop.
+ @item lim-expensive
+ The minimum cost of an expensive expression in the loop invariant motion.
+
@item hot-bb-count-fraction
Select fraction of the maximal count of repetitions of basic block in program
given basic block needs to have to be considered hot.
Index: doc/passes.texi
===================================================================
RCS file: /cvs/gcc/gcc/gcc/doc/passes.texi,v
retrieving revision 1.34
diff -c -3 -p -r1.34 passes.texi
*** doc/passes.texi 20 Jun 2004 21:31:32 -0000 1.34
--- doc/passes.texi 8 Jul 2004 15:52:51 -0000
*************** and is described by @code{pass_pre}.
*** 363,371 ****
@item Loop optimization
! TODO: Presumably we're going to do something with loops here. At
! present we don't, and this is a placeholder. The pass is located
! in @file{tree-ssa-loop.c} and is described by @code{pass_loop}.
@item Conditional constant propagation
--- 363,382 ----
@item Loop optimization
! The main driver of the pass is placed in @file{tree-ssa-loop.c}
! and described by @code{pass_loop}.
!
! The optimizations performed by this pass are:
!
! Loop invariant motion. This pass moves only invariants that
! would be hard to handle on rtl level (function calls, operations that expand to
! nontrivial sequences of insns). With @option{-funswitch-loops} it also moves
! operands of conditions that are invariant out of the loop, so that we can use
! just trivial invariantness analysis in loop unswitching. The pass also includes
! store motion. The pass is implemented in @file{tree-ssa-loop-im.c}.
!
! The optimizations also use various utility functions contained in
! @file{cfgloop.c}, @file{cfgloopanal.c} and @file{cfgloopmanip.c}.
@item Conditional constant propagation