[Bug tree-optimization/28364] poor optimization choices when iterating over a std::string (probably not c++-specific)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=28364

--- Comment #33 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Mon Apr 30 07:23:36 2018
New Revision: 259754

URL: https://gcc.gnu.org/viewcvs?rev=259754&root=gcc&view=rev
Log:
2018-04-30  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/28364
        PR tree-optimization/85275
        * tree-ssa-loop-ch.c (ch_base::copy_headers): Stop after
        copying first exit test.

        * gcc.dg/tree-ssa/copy-headers-5.c: New testcase.
        * gcc.dg/tree-ssa/predcom-8.c: Likewise.
        * gcc.dg/tree-ssa/cunroll-13.c: Rewrite to gimple testcase.
        * gcc.dg/tree-ssa/ivopt_mult_1.c: XFAIL.
        * gcc.dg/tree-ssa/ivopt_mult_1g.c: Add gimple variant that
        still passes.
        * gcc.dg/tree-ssa/ivopt_mult_2.c: XFAIL.
        * gcc.dg/tree-ssa/ivopt_mult_2g.c: Add gimple variant that
        still passes.
        * gcc.dg/tree-ssa/ssa-dom-thread-7.c: Adjust.
        * gcc.dg/tree-ssa/20030710-1.c: Likewise.
        * gcc.dg/tree-ssa/20030711-1.c: Likewise.

Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/copy-headers-5.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ivopt_mult_1g.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ivopt_mult_2g.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/predcom-8.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/tree-ssa/20030710-1.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/20030711-1.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/cunroll-13.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ivopt_mult_1.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ivopt_mult_2.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-7.c
    trunk/gcc/tree-ssa-loop-ch.c