[Bug rtl-optimization/64905] unsigned short is loaded with 4-byte load (movl)

["ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64905

Uroš Bizjak <ubizjak at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |law at redhat dot com
          Component|target                      |rtl-optimization

--- Comment #4 from Uroš Bizjak <ubizjak at gmail dot com> ---
It looks the failure is due to:

emit-rtl.c:  REGNO_POINTER_ALIGN (HARD_FRAME_POINTER_REGNUM) = STACK_BOUNDARY;

The testcase forces the pointer to %rbp (== HARD_FRAME_POINTER_REGNUM in the
above line), so the predicate thinks that the value in %rbp is aligned, since
%rbp has its REGNO_POINTER_ALIGN set to STACK_BOUNDARY.

Looks like generic RTL infrastructure problem to me, the
REGNO_POINTER_ALIGNMENT of hard_frame_pointer should be cleared when H_F_P is
omitted and reused.
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Subject: [Bug debug/64817] [5 Regression] compilation hangs at -O3 with -g enabled on x86_64-linux-gnu
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idd817

--- Comment #7 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Author: aoliva
Date: Wed Feb  4 14:23:33 2015
New Revision: 220404

URL: https://gcc.gnu.org/viewcvs?rev"0404&root=gcc&view=rev
Log:
Avoid allocating memory when trying but failing to simplify XOR of AND.

for  gcc/ChangeLog

    PR debug/64817
    * simplify-rtx.c (simplify_binary_operation_1): Rewrite
    simplification of XOR of AND to not allocate new rtx before
    committing to a simplification.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/simplify-rtx.c