[Bug tree-optimization/54027] [4.8 Regression] possible mis-optimization of signed left shift in c89 mode

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54027

--- Comment #5 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-08-10 
08:34:01 UTC ---
Author: rguenth
Date: Fri Aug 10 08:33:57 2012
New Revision: 190286

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=190286
Log:
2012-08-10  Richard Guenther  <rguent...@suse.de>

    PR tree-optimization/54027
    * tree-vrp.c (extract_range_from_binary_expr_1): Merge RSHIFT_EXPR
    and LSHIFT_EXPR handling, force -fwrapv for the multiplication used
    to handle LSHIFT_EXPR with a constant.

    * gcc.dg/torture/pr54027.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/pr54027.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-vrp.c