[Bug middle-end/46932] Inefficient code sequence to access local variable

[wilco at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46932

--- Comment #5 from Wilco <wilco at gcc dot gnu.org> ---
Author: wilco
Date: Wed Jul 26 10:49:17 2017
New Revision: 250564

URL: https://gcc.gnu.org/viewcvs?rev=250564&root=gcc&view=rev
Log:
Fix PR46932: Block auto increment on frame pointer

Block auto increment on frame pointer references.  This is never
beneficial since the SFP expands into SP+C or FP+C during register
allocation.  The generated code for the testcase is now as expected:

        str     x30, [sp, -32]!
        strb    w0, [sp, 31]
        add     x0, sp, 31
        bl      foo3
        ldr     x30, [sp], 32
        ret

    gcc/
        PR middle-end/46932
        * auto-inc-dec.c (parse_add_or_inc): Block autoinc on sfp.

    gcc/testsuite/
        PR middle-end/46932
        * gcc.dg/pr46932.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/pr46932.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/auto-inc-dec.c
    trunk/gcc/testsuite/ChangeLog