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From: "marxin at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/66278] New: Missed auto-vectorization of an array subtraction
Date: Mon, 25 May 2015 13:55:00 -0000 [thread overview]
Message-ID: <bug-66278-4@http.gcc.gnu.org/bugzilla/> (raw)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66278
Bug ID: 66278
Summary: Missed auto-vectorization of an array subtraction
Product: gcc
Version: 5.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: marxin at gcc dot gnu.org
Target Milestone: ---
Target: x86_64-linux-gnu
Hello.
In the following test case, we do not optimize assembly to utilize a vector
instruction.
$ cat vector.c
#include <stdint.h>
#define N 101
int main(int argc, char **argv)
{
uint32_t array[N][N][N];
const unsigned int next = argc == 3 ? 0 : 1;
for (unsigned i = next; i < N; i++)
array[3][3][i] = array[3][3][i] - 10;
return array[3][3][argc];
}
gcc 5.1.0 (same for GCC 4.8) with -O3 (http://goo.gl/zA7LMy):
main:
xorl %eax, %eax
subq $4121104, %rsp
cmpl $3, %edi
setne %al
.L2:
movl %eax, %edx
addl $1, %eax
subl $10, 123504(%rsp,%rdx,4)
cmpl $101, %eax
jne .L2
movslq %edi, %rdi
movl 123504(%rsp,%rdi,4), %eax
addq $4121104, %rsp
ret
icc 13.0.1 with -O3 (http://goo.gl/xzlz2C):
L__routine_start_main_0:
main:
pushq %rbp #6.1
movq %rsp, %rbp #6.1
andq $-128, %rsp #6.1
pushq %r12 #6.1
subq $4121208, %rsp #6.1
movl %edi, %r12d #6.1
movl $3, %edi #6.1
call __intel_new_proc_init #6.1
stmxcsr (%rsp) #6.1
movslq %r12d, %r12 #6.1
xorl %edi, %edi #9.37
movl $1, %esi #9.37
cmpq $3, %r12 #9.37
cmove %edi, %esi #9.37
orl $32832, (%rsp) #6.1
ldmxcsr (%rsp) #6.1
movl %esi, %ecx #11.3
negl %ecx #11.3
addl $101, %ecx #11.3
lea 123624(%rsp,%rsi,4), %rax #11.3
andq $15, %rax #11.3
movl %eax, %edx #11.3
negl %edx #11.3
addl $16, %edx #11.3
shrl $2, %edx #11.3
testl %eax, %eax #11.3
cmovne %edx, %eax #11.3
lea 4(%rax), %r8d #11.3
cmpl %r8d, %ecx #11.3
jl ..B1.16 # Prob 10% #11.3
movl %ecx, %edx #11.3
subl %eax, %edx #11.3
andl $3, %edx #11.3
negl %edx #11.3
addl %ecx, %edx #11.3
testl %eax, %eax #11.3
jbe ..B1.8 # Prob 10% #11.3
..B1.6: # Preds ..B1.4 ..B1.6
lea (%rsi,%rdi), %r8d #12.22
incl %edi #11.3
addl $-10, 123624(%rsp,%r8,4) #12.39
cmpl %eax, %edi #11.3
jb ..B1.6 # Prob 99% #11.3
..B1.8: # Preds ..B1.6 ..B1.4
movdqa .L_2il0floatpacket.2(%rip), %xmm0 #12.39
..B1.9: # Preds ..B1.9 ..B1.8
lea (%rsi,%rax), %edi #12.22
addl $4, %eax #11.3
cmpl %edx, %eax #11.3
movdqa 123624(%rsp,%rdi,4), %xmm1 #12.39
paddd %xmm0, %xmm1 #12.39
movdqa %xmm1, 123624(%rsp,%rdi,4) #12.5
jb ..B1.9 # Prob 99% #11.3
..B1.11: # Preds ..B1.9 ..B1.16
cmpl %ecx, %edx #11.3
jae ..B1.15 # Prob 10% #11.3
..B1.13: # Preds ..B1.11 ..B1.13
lea (%rsi,%rdx), %eax #12.22
incl %edx #11.3
addl $-10, 123624(%rsp,%rax,4) #12.39
cmpl %ecx, %edx #11.3
jb ..B1.13 # Prob 99% #11.3
..B1.15: # Preds ..B1.13 ..B1.11
movl 123624(%rsp,%r12,4), %eax #14.10
addq $4121208, %rsp #14.10
popq %r12 #14.10
movq %rbp, %rsp #14.10
popq %rbp #14.10
ret #14.10
..B1.16: # Preds ..B1.3 # Infreq
movl %edi, %edx #11.3
jmp ..B1.11 # Prob 100% #11.3
.L_2il0floatpacket.2:
.long 0xfffffff6,0xfffffff6,0xfffffff6,0xfffffff6
Thanks,
Martin
next reply other threads:[~2015-05-25 13:55 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-25 13:55 marxin at gcc dot gnu.org [this message]
2015-05-25 17:17 ` [Bug tree-optimization/66278] " jakub at gcc dot gnu.org
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