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[PATCH] Fix PR47566
- From: Richard Guenther <rguenther at suse dot de>
- To: gcc-patches at gcc dot gnu dot org
- Date: Wed, 2 Feb 2011 10:56:41 +0100 (CET)
- Subject: [PATCH] Fix PR47566
When inserting calls in PRE we do fold them, which, when presented
by an unfolded call can result in a load of stmts to appear
(like in the testcase the equivalent of sqrt(imag(x)**2+real(x)**2)).
This is not a problem in principle, but gimplifying the stmts causes
us to insert non-register temporaries when gimplifying save-exprs.
I'm not sure why save-expr gimplifying is not using registers, but
the following patch avoids using save-exprs around SSA_NAMEs which
is clearly unnecessary.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2011-02-02 Richard Guenther <rguenther@suse.de>
PR tree-optimization/47566
* builtins.c (builtin_save_expr): No SAVE_EXPR for SSA_NAMEs.
* gcc.dg/lto/20110201-1_0.c: New testcase.
Index: gcc/builtins.c
===================================================================
*** gcc/builtins.c (revision 169486)
--- gcc/builtins.c (working copy)
*************** target_char_cast (tree cst, char *p)
*** 652,660 ****
static tree
builtin_save_expr (tree exp)
{
! if (TREE_ADDRESSABLE (exp) == 0
! && (TREE_CODE (exp) == PARM_DECL
! || (TREE_CODE (exp) == VAR_DECL && !TREE_STATIC (exp))))
return exp;
return save_expr (exp);
--- 652,661 ----
static tree
builtin_save_expr (tree exp)
{
! if (TREE_CODE (exp) == SSA_NAME
! || (TREE_ADDRESSABLE (exp) == 0
! && (TREE_CODE (exp) == PARM_DECL
! || (TREE_CODE (exp) == VAR_DECL && !TREE_STATIC (exp)))))
return exp;
return save_expr (exp);
Index: gcc/testsuite/gcc.dg/lto/20110201-1_0.c
===================================================================
*** gcc/testsuite/gcc.dg/lto/20110201-1_0.c (revision 0)
--- gcc/testsuite/gcc.dg/lto/20110201-1_0.c (revision 0)
***************
*** 0 ****
--- 1,19 ----
+ /* { dg-lto-do run } */
+ /* { dg-lto-options { { -O0 -flto } } } */
+ /* { dg-extra-ld-options "-O2 -ffast-math -fuse-linker-plugin" } */
+ /* { dg-require-linker-plugin "" } */
+
+ /* We require a linker plugin because otherwise we'd need to link
+ against libm which we are not sure here has cabs on all targets.
+ This is because collect2 invokes ld on the -O0 object code
+ which does not have folded cabs. */
+
+ double cabs(_Complex double);
+ double __attribute__((used))
+ foo (_Complex double x, int b)
+ {
+ if (b)
+ x = 0;
+ return cabs(x);
+ }
+ int main() { return 0; }