https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85985
Bug ID: 85985
Summary: GCC >= 5.6 unaligned movaps
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: valentinp at mellanox dot com
Target Milestone: ---
Test case:
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
struct aaa {
void *a1;
void *a2;
struct {
void* a3
#if defined(USE_ALIGN) && USE_ALIGN > 0
__attribute__((aligned(64)))
#endif
;
};
};
struct bbb {
volatile int b;
struct aaa A;
};
static void print_A(struct aaa *A) {
printf("a1: %p, %%8=%lu %%16=%lu %%32=%lu\na2: %p, %%8=%lu %%16=%lu
%%32=%lu\n",
&A->a1, ((uint64_t)(&A->a1)) % 8, ((uint64_t)(&A->a1)) % 16,
((uint64_t)(&A->a1)) % 32,
&A->a2, ((uint64_t)(&A->a2)) % 8, ((uint64_t)(&A->a2)) % 16,
((uint64_t)(&A->a2)) % 32);
}
static void __attribute__ ((noinline)) B_init(struct bbb *B) {
B->A.a2 = NULL;
B->A.a1 = NULL;
}
int main(int argc, char *argv[])
{
struct bbb *B;
void *storage = malloc(sizeof(struct bbb)*32);
B = (struct bbb*)((char*)storage + 8);
print_A(&B->A);
B_init(B);
free(storage);
return 0;
}
ASM:
.file "compiler2.c"
.text
.p2align 4,,15
.type B_init, @function
B_init:
.LFB42:
.cfi_startproc
pxor %xmm0, %xmm0
movaps %xmm0, 64(%rdi)
ret
.cfi_endproc
.LFE42:
.size B_init, .-B_init
.section .rodata.str1.8,"aMS",@progbits,1
.align 8
.LC0:
.string "a1: %p, %%8=%lu %%16=%lu %%32=%lu\na2: %p, %%8=%lu %%16=%lu
%%32=%lu\n"
.section .text.startup,"ax",@progbits
.p2align 4,,15
.globl main
.type main, @function
main:
.LFB43:
.cfi_startproc
pushq %rbx
.cfi_def_cfa_offset 16
.cfi_offset 3, -16
movl $6144, %edi
call malloc@PLT
leaq 74(%rax), %rdx
movq %rax, %rbx
leaq 82(%rax), %rax
leaq .LC0(%rip), %rsi
movl $1, %edi
movq %rax, %rcx
movq %rdx, %r9
movq %rdx, %r8
andl $31, %ecx
andl $31, %r9d
andl $15, %r8d
pushq %rcx
.cfi_def_cfa_offset 24
movq %rax, %rcx
andl $15, %ecx
pushq %rcx
.cfi_def_cfa_offset 32
pushq $2
.cfi_def_cfa_offset 40
movl $2, %ecx
pushq %rax
.cfi_def_cfa_offset 48
xorl %eax, %eax
call __printf_chk@PLT
leaq 10(%rbx), %rdi
addq $32, %rsp
.cfi_def_cfa_offset 16
call B_init
movq %rbx, %rdi
call free@PLT
xorl %eax, %eax
popq %rbx
.cfi_def_cfa_offset 8
ret
.cfi_endproc
.LFE43:
.size main, .-main
.ident "GCC: (Ubuntu 7.2.0-8ubuntu3.2) 7.2.0"
.section .note.GNU-stack,"",@progbits
gcc --version
gcc (Ubuntu 7.2.0-8ubuntu3.2) 7.2.0
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
compile:
gcc -v --save-temps -O3 -o ccc -DUSE_ALIGN=1 -Wall -Wextra compiler2.c
Description:
test always works with GCC 4.6
test works with GCC >= 5.6 and -DUSE_ALIGN=0
test segv on unaligned movaps with GCC >= 5.6 (latest tested GCC 7.2) and
-DUSE_ALIGN=1
This may be a duplicate of https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84525
but the test case here is different. Am I violating the spec with this test?
