[Bug tree-optimization/59058] [4.7/4.8/4.9 Regression] wrong code at -O3 on x86_64-linux-gnu (affecting gcc 4.6 to trunk)

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59058

--- Comment #13 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Fri Dec  6 09:23:07 2013
New Revision: 205730

URL: http://gcc.gnu.org/viewcvs?rev=205730&root=gcc&view=rev
Log:
2013-12-06  Richard Biener  <rguenther@suse.de>

    PR tree-optimization/59058
    * tree-vectorizer.h (struct _loop_vec_info): Add num_itersm1
    member.
    (LOOP_VINFO_NITERSM1): New macro.
    * tree-vect-loop-manip.c (slpeel_tree_peel_loop_to_edge): Express
    the vector loop entry test in terms of scalar latch executions.
    (vect_do_peeling_for_alignment): Update LOOP_VINFO_NITERSM1.
    * tree-vect-loop.c (vect_get_loop_niters): Also return the
    number of latch executions.
    (new_loop_vec_info): Initialize LOOP_VINFO_NITERSM1.
    (vect_analyze_loop_form): Likewise.
    (vect_generate_tmps_on_preheader): Compute the number of
    vectorized iterations differently.

    * gcc.dg/torture/pr59058.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/pr59058.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-vect-loop-manip.c
    trunk/gcc/tree-vect-loop.c
    trunk/gcc/tree-vectorizer.h