[Bug rtl-optimization/78812] [5/6/7 Regression] Wrong code generation due to hoisting memory load across function call

[law at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78812

--- Comment #14 from Jeffrey A. Law <law at gcc dot gnu.org> ---
Author: law
Date: Thu Jan  5 07:38:48 2017
New Revision: 244093

URL: https://gcc.gnu.org/viewcvs?rev=244093&root=gcc&view=rev
Log:
        PR tree-optimizatin/78812
        * rtl.h (contains_mem_rtx_p): Prototype.
        * ifcvt.c (containts_mem_rtx_p): Move from here to...
        * rtlanal.c (contains_mem_rtx_p): Here and remvoe static linkage.
        * gcse.c (prune_expressions): Use contains_mem_rtx_p to discover
        and prune MEMs that are not at the toplevel of a SET_SRC rtx.  Look
        through ZERO_EXTEND and SIGN_EXTEND when trying to avoid pruning
        MEMs.

        PR tree-optimization/78812
        * g++.dg/torture/pr78812.C: New test.

Added:
    trunk/gcc/testsuite/g++.dg/torture/pr78812.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/gcse.c
    trunk/gcc/ifcvt.c
    trunk/gcc/rtl.h
    trunk/gcc/rtlanal.c
    trunk/gcc/testsuite/ChangeLog