[Bug tree-optimization/69047] memcpy is not as optimized as union is

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69047

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Fri Aug 26 12:33:43 2016
New Revision: 239778

URL: https://gcc.gnu.org/viewcvs?rev=239778&root=gcc&view=rev
Log:
2016-08-26  Richard Biener  <rguenther@suse.de>

        PR tree-optimization/69047
        * tree-ssa.c (maybe_rewrite_mem_ref_base): Handle general bitfield
        extracts similar to what FRE does.
        (non_rewritable_mem_ref_base): Likewise.

        * gcc.dg/pr69047.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/pr69047.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa.c