https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125100
Bug ID: 125100
Summary: CONST_VECTOR in REG_EQUAL note isn't checked
Product: gcc
Version: 16.0
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
CONST_VECTOR in REG_EQUAL note isn't checked
(gdb) call debug (insn)
(insn 51 14 91 3 (set (reg:V2QI 120)
(mem/u/c:V2QI (plus:SI (reg:SI 98)
(const:SI (unspec:SI [
(symbol_ref/u:SI ("*.LC0") [flags 0x2])
] UNSPEC_GOTOFF))) [0 S2 A16])) 2089
{*movv2qi_internal}
(expr_list:REG_DEAD (reg:SI 98)
(expr_list:REG_EQUAL (const_vector:V2QI [
(const_int -1 [0xffffffffffffffff]) repeated x2
])
(nil))))
(gdb)
This can be changed to
(gdb) call debug (insn)
(insn 51 14 91 3 (set (subreg:HI (reg:V2QI 120) 0)
(const_int -1 [0xffffffffffffffff])) 101 {*movhi_internal}
(expr_list:REG_DEAD (reg:SI 98)
(expr_list:REG_EQUAL (const_vector:V2QI [
(const_int -1 [0xffffffffffffffff]) repeated x2
])
(nil))))
(gdb)
[hjl@gnu-zen4-1 pr125026]$ cat bar-2.c
struct desc {
char c1;
char c2;
};
void
foo (struct desc *list, int n, int l)
{
int j;
for (j = 0; j < l; j++)
list[j].c1 = list[j].c2 = -1;
for (;j < n; j++)
list[j].c1 = list[j].c2 = -1;
}
[hjl@gnu-zen4-1 pr125026]$
/export/build/gnu/tools-build/gcc-release-debug/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/tools-build/gcc-release-debug/build-x86_64-linux/gcc/ -m32
-mtune=generic -O2 -fPIC -march=pentiumpro -S bar-2.c
[hjl@gnu-zen4-1 pr125026]$ cat bar-2.s
.file "bar-2.c"
.text
.p2align 4
.globl foo
.type foo, @function
foo:
.LFB0:
.cfi_startproc
pushl %edi
.cfi_def_cfa_offset 8
.cfi_offset 7, -8
pushl %esi
.cfi_def_cfa_offset 12
.cfi_offset 6, -12
call __x86.get_pc_thunk.si
addl $_GLOBAL_OFFSET_TABLE_, %esi
pushl %ebx
.cfi_def_cfa_offset 16
.cfi_offset 3, -16
movl 24(%esp), %ecx
movl 16(%esp), %ebx
testl %ecx, %ecx
jle .L6
movzwl .LC0@GOTOFF(%esi), %edx
movl %ebx, %eax
leal (%ebx,%ecx,2), %edi
testb $1, %cl
je .L3
leal 2(%ebx), %eax
movw %dx, (%ebx)
cmpl %edi, %eax
je .L2
.p2align 4
.p2align 4
.p2align 3
.L3:
movw %dx, (%eax)
addl $4, %eax
movw %dx, -2(%eax)
cmpl %edi, %eax
jne .L3
.L2:
cmpl %ecx, 20(%esp)
jle .L1
movl 20(%esp), %edi
leal (%ebx,%ecx,2), %eax
movzwl .LC0@GOTOFF(%esi), %edx
leal (%ebx,%edi,2), %ecx
movl %ecx, %ebx
subl %eax, %ebx
andl $2, %ebx
je .L5
movw %dx, (%eax)
addl $2, %eax
cmpl %ecx, %eax
je .L1
.p2align 4
.p2align 4
.p2align 3
.L5:
movw %dx, (%eax)
addl $4, %eax
movw %dx, -2(%eax)
cmpl %ecx, %eax
jne .L5
.L1:
popl %ebx
.cfi_remember_state
.cfi_restore 3
.cfi_def_cfa_offset 12
popl %esi
.cfi_restore 6
.cfi_def_cfa_offset 8
popl %edi
.cfi_restore 7
.cfi_def_cfa_offset 4
ret
.p2align 4,,10
.p2align 3
.L6:
.cfi_restore_state
xorl %ecx, %ecx
jmp .L2
.cfi_endproc
.LFE0:
.size foo, .-foo
.section .rodata.cst2,"aM",@progbits,2
.align 2
.LC0:
.byte -1
.byte -1
.section
.text.__x86.get_pc_thunk.si,"axG",@progbits,__x86.get_pc_thunk.si,comdat
.globl __x86.get_pc_thunk.si
.hidden __x86.get_pc_thunk.si
.type __x86.get_pc_thunk.si, @function
__x86.get_pc_thunk.si:
.LFB1:
.cfi_startproc
movl (%esp), %esi
ret
.cfi_endproc
.LFE1:
.ident "GCC: (GNU) 16.0.1 20260429 (prerelease)"
.section .note.GNU-stack,"",@progbits
[hjl@gnu-zen4-1 pr125026]$
