[Bug rtl-optimization/67609] [5 Regression] Generates wrong code for SSE2 _mm_load_pd

[rth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67609

--- Comment #37 from Richard Henderson <rth at gcc dot gnu.org> ---
Author: rth
Date: Wed Nov 18 15:45:26 2015
New Revision: 230552

URL: https://gcc.gnu.org/viewcvs?rev=230552&root=gcc&view=rev
Log:
PR rtl-opt/67609

        Backport from mainline
        * config/i386/i386.c (ix86_cannot_change_mode_class): Tighten
        sse check to the exact conditions of PR 67609. 

        * config/i386/i386.c (ix86_cannot_change_mode_class): Disallow
        narrowing subregs on SSE and MMX registers.
        * doc/tm.texi.in (CANNOT_CHANGE_MODE_CLASS): Clarify when subregs that
        appear to be sub-words of multi-register pseudos must be rejected.
        * doc/tm.texi: Regenerate.

Added:
    branches/gcc-5-branch/gcc/testsuite/gcc.target/i386/pr67609-2.c
    branches/gcc-5-branch/gcc/testsuite/gcc.target/i386/pr67609.c
Modified:
    branches/gcc-5-branch/gcc/ChangeLog
    branches/gcc-5-branch/gcc/config/i386/i386.c
    branches/gcc-5-branch/gcc/doc/tm.texi
    branches/gcc-5-branch/gcc/doc/tm.texi.in