[PATCH] Teach SCCVN about VIEW_CONVERT_EXPR simplifying, add some foldings
Richard Guenther
rguenther@suse.de
Mon Mar 3 11:54:00 GMT 2008
This is a preparatory patch for teaching type-punnning to SCCVN which
I'll apply separately to make the two proposal patches smaller. It
adds folding of VIEW_CONVERT_EXPR of same-precision integral types
and pointer types as well as teaching SCCVN to combine VIEW_CONVERT_EXPR
the same as it does for NOP_EXPR and REAL/IMAGPART_EXPR.
It also fixes two latent problems, may_be_nonaddressable_p in IVOPTS
(again) and SCCVN inserting struct copy RHS into its expression tables.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2008-02-29 Richard Guenther <rguenther@suse.de>
* fold-const.c (fold_unary): Fold VIEW_CONVERT_EXPR of
integral and pointer arguments which do not change the
precision to NOP_EXPRs.
* tree-ssa-loop-ivopts.c (may_be_nonaddressable_p): Adjust
VIEW_CONVERT_EXPR case.
Index: gcc/fold-const.c
===================================================================
*** gcc/fold-const.c 2008-03-01 19:51:04.000000000 +0100
--- gcc/fold-const.c 2008-03-01 19:53:25.000000000 +0100
*************** fold_unary (enum tree_code code, tree ty
*** 8277,8289 ****
case VIEW_CONVERT_EXPR:
if (TREE_TYPE (op0) == type)
return op0;
! if (TREE_CODE (op0) == VIEW_CONVERT_EXPR
! || (TREE_CODE (op0) == NOP_EXPR
! && INTEGRAL_TYPE_P (TREE_TYPE (op0))
! && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (op0, 0)))
! && TYPE_PRECISION (TREE_TYPE (op0))
! == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
return fold_build1 (VIEW_CONVERT_EXPR, type, TREE_OPERAND (op0, 0));
return fold_view_convert_expr (type, op0);
case NEGATE_EXPR:
--- 8277,8304 ----
case VIEW_CONVERT_EXPR:
if (TREE_TYPE (op0) == type)
return op0;
! if (TREE_CODE (op0) == VIEW_CONVERT_EXPR)
return fold_build1 (VIEW_CONVERT_EXPR, type, TREE_OPERAND (op0, 0));
+
+ /* For integral conversions with the same precision or pointer
+ conversions use a NOP_EXPR instead. */
+ if ((INTEGRAL_TYPE_P (type) && INTEGRAL_TYPE_P (TREE_TYPE (op0))
+ && TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (op0))
+ /* Do not muck with VIEW_CONVERT_EXPRs that convert from
+ a sub-type to its base type as generated by the Ada FE. */
+ && !TREE_TYPE (TREE_TYPE (op0)))
+ || (POINTER_TYPE_P (type) && POINTER_TYPE_P (TREE_TYPE (op0))))
+ return fold_convert (type, op0);
+
+ /* Strip inner integral conversions that do not change the precision. */
+ if ((TREE_CODE (op0) == NOP_EXPR
+ || TREE_CODE (op0) == CONVERT_EXPR)
+ && INTEGRAL_TYPE_P (TREE_TYPE (op0))
+ && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (op0, 0)))
+ && (TYPE_PRECISION (TREE_TYPE (op0))
+ == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
+ return fold_build1 (VIEW_CONVERT_EXPR, type, TREE_OPERAND (op0, 0));
+
return fold_view_convert_expr (type, op0);
case NEGATE_EXPR:
Index: gcc/tree-ssa-loop-ivopts.c
===================================================================
*** gcc/tree-ssa-loop-ivopts.c 2008-03-01 19:51:04.000000000 +0100
--- gcc/tree-ssa-loop-ivopts.c 2008-03-01 19:53:25.000000000 +0100
*************** may_be_nonaddressable_p (tree expr)
*** 1522,1529 ****
and make them look addressable. After some processing the
non-addressability may be uncovered again, causing ADDR_EXPRs
of inappropriate objects to be built. */
! if (AGGREGATE_TYPE_P (TREE_TYPE (expr))
! && !AGGREGATE_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0))))
return true;
/* ... fall through ... */
--- 1522,1529 ----
and make them look addressable. After some processing the
non-addressability may be uncovered again, causing ADDR_EXPRs
of inappropriate objects to be built. */
! if (is_gimple_reg (TREE_OPERAND (expr, 0))
! || is_gimple_min_invariant (TREE_OPERAND (expr, 0)))
return true;
/* ... fall through ... */
2008-02-29 Richard Guenther <rguenther@suse.de>
* tree-ssa-sccvn.c (visit_reference_op_store): Do not insert
struct copies into the expression table.
(simplify_unary_expression): Handle VIEW_CONVERT_EXPR.
(try_to_simplify): Likewise.
Index: gcc/tree-ssa-sccvn.c
===================================================================
*** gcc/tree-ssa-sccvn.c 2008-03-01 19:53:24.000000000 +0100
--- gcc/tree-ssa-sccvn.c 2008-03-01 19:53:24.000000000 +0100
*************** visit_reference_op_store (tree lhs, tree
*** 1311,1317 ****
changed |= set_ssa_val_to (vdef, vdef);
}
! vn_reference_insert (lhs, op, vdefs);
}
else
{
--- 1365,1374 ----
changed |= set_ssa_val_to (vdef, vdef);
}
! /* Do not insert structure copies into the tables. */
! if (is_gimple_min_invariant (op)
! || is_gimple_reg (op))
! vn_reference_insert (lhs, op, vdefs);
}
else
{
*************** simplify_unary_expression (tree rhs)
*** 1549,1561 ****
else if (TREE_CODE (rhs) == NOP_EXPR
|| TREE_CODE (rhs) == CONVERT_EXPR
|| TREE_CODE (rhs) == REALPART_EXPR
! || TREE_CODE (rhs) == IMAGPART_EXPR)
{
/* We want to do tree-combining on conversion-like expressions.
Make sure we feed only SSA_NAMEs or constants to fold though. */
tree tem = valueize_expr (VN_INFO (op0)->expr);
if (UNARY_CLASS_P (tem)
|| BINARY_CLASS_P (tem)
|| TREE_CODE (tem) == SSA_NAME
|| is_gimple_min_invariant (tem))
op0 = tem;
--- 1606,1620 ----
else if (TREE_CODE (rhs) == NOP_EXPR
|| TREE_CODE (rhs) == CONVERT_EXPR
|| TREE_CODE (rhs) == REALPART_EXPR
! || TREE_CODE (rhs) == IMAGPART_EXPR
! || TREE_CODE (rhs) == VIEW_CONVERT_EXPR)
{
/* We want to do tree-combining on conversion-like expressions.
Make sure we feed only SSA_NAMEs or constants to fold though. */
tree tem = valueize_expr (VN_INFO (op0)->expr);
if (UNARY_CLASS_P (tem)
|| BINARY_CLASS_P (tem)
+ || TREE_CODE (tem) == VIEW_CONVERT_EXPR
|| TREE_CODE (tem) == SSA_NAME
|| is_gimple_min_invariant (tem))
op0 = tem;
*************** try_to_simplify (tree stmt, tree rhs)
*** 1607,1613 ****
/* Fallthrough for some codes that can operate on registers. */
if (!(TREE_CODE (rhs) == REALPART_EXPR
! || TREE_CODE (rhs) == IMAGPART_EXPR))
break;
/* We could do a little more with unary ops, if they expand
into binary ops, but it's debatable whether it is worth it. */
--- 1666,1673 ----
/* Fallthrough for some codes that can operate on registers. */
if (!(TREE_CODE (rhs) == REALPART_EXPR
! || TREE_CODE (rhs) == IMAGPART_EXPR
! || TREE_CODE (rhs) == VIEW_CONVERT_EXPR))
break;
/* We could do a little more with unary ops, if they expand
into binary ops, but it's debatable whether it is worth it. */
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