[Bug middle-end/53623] [4.7/4.8/4.9 Regression] sign extension is effectively split into two x86-64 instructions

[law at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53623

--- Comment #9 from Jeffrey A. Law <law at gcc dot gnu.org> ---
Author: law
Date: Wed Jan  8 06:03:12 2014
New Revision: 206418

URL: http://gcc.gnu.org/viewcvs?rev=206418&root=gcc&view=rev
Log:
    PR middle-end/53623
    * ree.c (combine_set_extension): Handle case where source
    and destination registers in an extension insn are different.
    (combine_reaching_defs): Allow source and destination
    registers in extension to be different under limited
    circumstances.
    (add_removable_extension): Remove restriction that the
    source and destination registers in the extension are the
    same.
    (find_and_remove_re): Emit a copy from the extension's
    destination to its source after the defining insn if
    the source and destination registers are different.

    PR middle-end/53623
    * gcc.target/i386/pr53623.c: New test.

Added:
    trunk/gcc/testsuite/gcc.target/i386/pr53623.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/ree.c
    trunk/gcc/testsuite/ChangeLog