[Bug target/83905] ix86_expand_epilogue modifies the copy of cfun->machine->frame

[hjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83905

--- Comment #3 from hjl at gcc dot gnu.org <hjl at gcc dot gnu.org> ---
Author: hjl
Date: Sat Jan 27 13:10:24 2018
New Revision: 257123

URL: https://gcc.gnu.org/viewcvs?rev=257123&root=gcc&view=rev
Log:
i386: Use const reference of struct ix86_frame to avoid copy

We can use const reference of struct ix86_frame to avoid making a local
copy of ix86_frame.  ix86_expand_epilogue makes a local copy of struct
ix86_frame and uses the reg_save_offset field as a local variable.  This
patch uses a separate local variable for reg_save_offset.

Tested on x86-64 with ada.

        Backport from mainline
        PR target/83905
        * config/i386/i386.c (ix86_expand_prologue): Use cost reference
        of struct ix86_frame.
        (ix86_expand_epilogue): Likewise.  Add a local variable for
        the reg_save_offset field in struct ix86_frame.

Modified:
    branches/gcc-7-branch/gcc/ChangeLog
    branches/gcc-7-branch/gcc/config/i386/i386.c