[Bug target/61904] Incorrect stack red-zoning on x86-64 code generation

["rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61904

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |UNCONFIRMED
     Ever confirmed|1                           |0

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
With both the FSF 4.9.0 and 4.9.1 releases and

gcc -S t.i -mno-80387 -mno-fp-ret-in-387 -mpreferred-stack-boundary=3
-mtune=generic -mno-red-zone -mcmodel=kernel -maccumulate-outgoing-args
-mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx -march=x86-64 -g -Os
-fno-strict-aliasing -fno-common -fno-asynchronous-unwind-tables
-fno-omit-frame-pointer

(too many options only to guess from the .s file - can you please specify
explicitely passed options?)


load_balance:
.LFB2409:
        .loc 2 6487 0
.LVL1260:
        pushq   %rbp
.LCFI442:
        movq    %rsp, %rbp
.LCFI443:
        pushq   %r15
        pushq   %r14
        pushq   %r13
        pushq   %r12
.LCFI444:
        movq    %rdx, %r12
        pushq   %rbx
.LBB2812:
        .loc 2 6493 0
        movq    $load_balance_mask, -376(%rbp)
.LBE2812:
        .loc 2 6487 0
        subq    $416, %rsp
.LCFI445:
        .loc 2 6489 0
        movq    (%rdx), %rax
        .loc 2 6487 0
        movl    %edi, -392(%rbp)
        movl    %ecx, -388(%rbp)
        movq    %r8, -456(%rbp)
        .loc 2 6489 0
        movq    %rax, -424(%rbp)
.LVL1261:
.LBB2813:
        .loc 2 6493 0
        movq    -376(%rbp), %rax
.LVL1262:
#APP
# 6493 "kernel/sched/fair.c" 1
        add %gs:this_cpu_off, %rax
# 0 "" 2
#NO_APP


which I guess is equally bad (even if not matching the output from Michel).
It seems to be triggered by -g or -fvar-tracking and is fixed on the 4.9
branch - so it might be a duplicate of PR61801.