[Bug middle-end/81657] New: [8 Regression] FAIL: gcc.dg/20050503-1.c scan-assembler-not call

["hjl.tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81657

            Bug ID: 81657
           Summary: [8 Regression] FAIL: gcc.dg/20050503-1.c
                    scan-assembler-not call
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hjl.tools at gmail dot com
                CC: marxin at gcc dot gnu.org
  Target Milestone: ---

On Linux/x86, r250789 caused:

FAIL: gcc.dg/20050503-1.c scan-assembler-not call

since tail call optimization is no longer applied to mempcpy.  We
are generating:

test2a:
.LFB2:
        .cfi_startproc
        pushq   %rbx
        .cfi_def_cfa_offset 16
        .cfi_offset 3, -16
        movq    %rdx, %rbx
        call    memcpy
        addq    %rbx, %rax
        popq    %rbx
        .cfi_def_cfa_offset 8
        ret

instead of

test2a:
.LFB2:
        .cfi_startproc
        jmp     mempcpy
        .cfi_endproc