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re PR tree-optimization/31146 (forwprop does not look through casts)

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2007-05-02  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/31146
	* tree-ssa-forwprop.c (forward_propagate_addr_expr_1): New
	argument, single_use_p.  If we have a single use that is
	a conversion to the definition rhs type, propagate that rhs.
	(forward_propagate_addr_expr): Pass single_use_p argument
	to forward_propagate_addr_expr_1.

	* g++.dg/tree-ssa/pr31146-2.C: New testcase.

From-SVN: r124349
This commit is contained in:
Richard Guenther 2007-05-02 09:12:49 +00:00 committed by Richard Biener
parent d7598e110d
commit f6c5fefc1d
4 changed files with 55 additions and 4 deletions
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9
gcc/ChangeLog
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@ -1,3 +1,12 @@
2007-05-02 Richard Guenther <rguenther@suse.de>
PR tree-optimization/31146
* tree-ssa-forwprop.c (forward_propagate_addr_expr_1): New
argument, single_use_p. If we have a single use that is
a conversion to the definition rhs type, propagate that rhs.
(forward_propagate_addr_expr): Pass single_use_p argument
to forward_propagate_addr_expr_1.
2007-05-01 H.J. Lu <hongjiu.lu@intel.com> 2007-05-01 H.J. Lu <hongjiu.lu@intel.com>
* config/i386/i386.c (ix86_expand_sse_comi): Remove unused * config/i386/i386.c (ix86_expand_sse_comi): Remove unused

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2007-05-02 Richard Guenther <rguenther@suse.de>
PR tree-optimization/31146
* g++.dg/tree-ssa/pr31146-2.C: New testcase.
2007-05-01 Geoffrey Keating <geoffk@apple.com> 2007-05-01 Geoffrey Keating <geoffk@apple.com>
* gcc.c-torture/compile/limits-blockid.c: New. * gcc.c-torture/compile/limits-blockid.c: New.

24
gcc/testsuite/g++.dg/tree-ssa/pr31146-2.C Normal file
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@ -0,0 +1,24 @@
/* { dg-do compile } */
/* { dg-options "-O -fdump-tree-forwprop1" } */
#include <new>
template <class T>
struct Vec
{
Vec()
{
for (int i=0; i<3; ++i)
new (&a[i]) T(0);
}
T a[3];
};
double foo (void)
{
Vec<double> v;
return v.a[2];
}
/* { dg-final { scan-tree-dump "Replaced .*iftmp.* != 0B. with .1" "forwprop1" } } */
/* { dg-final { cleanup-tree-dump "forwprop1" } } */

21
gcc/tree-ssa-forwprop.c
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@ -559,7 +559,8 @@ forward_propagate_addr_into_variable_array_index (tree offset, tree lhs,
be not totally successful, yet things may have been changed). */ be not totally successful, yet things may have been changed). */
static bool static bool
forward_propagate_addr_expr_1 (tree name, tree def_rhs, tree use_stmt) forward_propagate_addr_expr_1 (tree name, tree def_rhs, tree use_stmt,
bool single_use_p)
{ {
tree lhs, rhs, array_ref; tree lhs, rhs, array_ref;
@ -584,10 +585,20 @@ forward_propagate_addr_expr_1 (tree name, tree def_rhs, tree use_stmt)
/* Continue propagating into the RHS. */ /* Continue propagating into the RHS. */
} }
/* Trivial case. The use statement could be a trivial copy or a /* Trivial cases. The use statement could be a trivial copy or a
useless conversion. Recurse to the uses of the lhs as copyprop does useless conversion. Recurse to the uses of the lhs as copyprop does
not copy through differen variant pointers and FRE does not catch not copy through differen variant pointers and FRE does not catch
all useless conversions. */ all useless conversions. Treat the case of a single-use name and
a conversion to def_rhs type separate, though. */
else if (TREE_CODE (lhs) == SSA_NAME
&& (TREE_CODE (rhs) == NOP_EXPR
|| TREE_CODE (rhs) == CONVERT_EXPR)
&& TREE_TYPE (rhs) == TREE_TYPE (def_rhs)
&& single_use_p)
{
GIMPLE_STMT_OPERAND (use_stmt, 1) = unshare_expr (def_rhs);
return true;
}
else if ((TREE_CODE (lhs) == SSA_NAME else if ((TREE_CODE (lhs) == SSA_NAME
&& rhs == name) && rhs == name)
|| ((TREE_CODE (rhs) == NOP_EXPR || ((TREE_CODE (rhs) == NOP_EXPR
@ -702,6 +713,7 @@ forward_propagate_addr_expr (tree name, tree rhs)
imm_use_iterator iter; imm_use_iterator iter;
tree use_stmt; tree use_stmt;
bool all = true; bool all = true;
bool single_use_p = has_single_use (name);
FOR_EACH_IMM_USE_STMT (use_stmt, iter, name) FOR_EACH_IMM_USE_STMT (use_stmt, iter, name)
{ {
@ -726,7 +738,8 @@ forward_propagate_addr_expr (tree name, tree rhs)
push_stmt_changes (&use_stmt); push_stmt_changes (&use_stmt);
result = forward_propagate_addr_expr_1 (name, rhs, use_stmt); result = forward_propagate_addr_expr_1 (name, rhs, use_stmt,
single_use_p);
all &= result; all &= result;
pop_stmt_changes (&use_stmt); pop_stmt_changes (&use_stmt);