[Bug target/81769] New: Unnecessary stack realign with -mavx

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81769

            Bug ID: 81769
           Summary: Unnecessary stack realign with -mavx
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hjl.tools at gmail dot com
  Target Milestone: ---
            Target: x86

[hjl@gnu-6 pr59501]$ cat k.i
typedef int v8si __attribute__ ((vector_size (32)));

void
foo (unsigned long long *idx, v8si *out_start, v8si *regions)
{
  if (*idx < 20 ) {
    v8si base = regions[*idx];
    *out_start = base;
  }
}
[hjl@gnu-6 pr59501]$ make k.s
/export/build/gnu/gcc/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -O -mregparm=3 -m32 -mavx -S
k.i
[hjl@gnu-6 pr59501]$ cat k.s
        .file   "k.i"
        .text
        .globl  foo
        .type   foo, @function
foo:
.LFB0:
        .cfi_startproc
        pushl   %ebp
        .cfi_def_cfa_offset 8
        .cfi_offset 5, -8
        movl    %esp, %ebp
        .cfi_def_cfa_register 5
        pushl   %ebx
        andl    $-32, %esp  <<<<<<<<<<< This isn't needed.
        .cfi_offset 3, -12
        movl    (%eax), %ebx
        cmpl    $0, 4(%eax)
        jne     .L1
        cmpl    $19, %ebx
        ja      .L1
        sall    $5, %ebx
        vmovdqa (%ecx,%ebx), %ymm0
        vmovdqa %ymm0, (%edx)
.L1:
        movl    -4(%ebp), %ebx
        leave
        .cfi_restore 5
        .cfi_restore 3
        .cfi_def_cfa 4, 4
        ret
        .cfi_endproc
.LFE0:
        .size   foo, .-foo
        .ident  "GCC: (GNU) 8.0.0 20170807 (experimental)"
        .section        .note.GNU-stack,"",@progbits
[hjl@gnu-6 pr59501]$