[Bug rtl-optimization/88796] -fstack-protector* kills RTL DSE opportunities

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88796

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Mon Jan 14 12:01:01 2019
New Revision: 267916

URL: https://gcc.gnu.org/viewcvs?rev=267916&root=gcc&view=rev
Log:
        PR rtl-optimization/88796
        * emit-rtl.h (struct rtl_data): Add stack_protect_guard_decl field.
        * cfgexpand.c (stack_protect_prologue): Initialize
        crtl->stack_protect_guard_decl.
        * function.c (stack_protect_epilogue): Use it instead of calling
        targetm.stack_protect_guard again.
        * dse.c (check_mem_read_rtx): Ignore MEM_VOLATILE_P reads from
        MEMs with MEM_EXPR equal to crtl->stack_protect_guard or
        crtl->stack_protect_guard_decl.
        * config/i386/i386.c (ix86_stack_protect_guard): Set TREE_THIS_VOLATILE
        on the returned MEM_EXPR.

        * gcc.target/i386/pr88796.c: New test.

Added:
    trunk/gcc/testsuite/gcc.target/i386/pr88796.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/cfgexpand.c
    trunk/gcc/config/i386/i386.c
    trunk/gcc/dse.c
    trunk/gcc/emit-rtl.h
    trunk/gcc/function.c
    trunk/gcc/testsuite/ChangeLog