[Bug tree-optimization/58143] [4.8/4.9 regression] wrong code at -O3

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58143

--- Comment #30 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Thu Oct 17 09:59:47 2013
New Revision: 203745

URL: http://gcc.gnu.org/viewcvs?rev=203745&root=gcc&view=rev
Log:
2013-10-17  Richard Biener  <rguenther@suse.de>

    PR tree-optimization/58143
    * tree-ssa-loop-im.c (arith_code_with_undefined_signed_overflow):
    New function.
    (rewrite_to_defined_overflow): Likewise.
    (move_computations_dom_walker::before_dom): Rewrite stmts
    with undefined signed overflow that are not always executed
    into unsigned arithmetic.

    * gcc.dg/torture/pr58143-1.c: New testcase.
    * gcc.dg/torture/pr58143-2.c: Likewise.
    * gcc.dg/torture/pr58143-3.c: Likewise.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/pr58143-1.c
    trunk/gcc/testsuite/gcc.dg/torture/pr58143-2.c
    trunk/gcc/testsuite/gcc.dg/torture/pr58143-3.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-loop-im.c