https://llvm.org/bugs/show_bug.cgi?id=30375
Bug ID: 30375
Summary: Regression in Clang-4.0.0's optimizer
Product: new-bugs
Version: trunk
Hardware: PC
OS: Linux
Status: NEW
Severity: normal
Priority: P
Component: new bugs
Assignee: unassignedb...@nondot.org
Reporter: ishiura-compi...@ml.kwansei.ac.jp
CC: llvm-bugs@lists.llvm.org
Classification: Unclassified
We compiled a program (A.c) by clang-4.0.0 and clang-3.6.2 with -O3 option.
clang-3.6.2 performed better optimization than clang-4.0.0.
(A.c)
int x0 = 1;
int main ()
{
int x1 = 1;
int t0 = 2 / ((1 / x0) && x1);
if (t0 != 2) __builtin_abort();
return 0;
}
+-------------------------------+--------------------------------+
|clang-4.0.0.s |clang-3.6.2.s |
|(clang-4.0.0 A.c -O3 -S) |(clang-3.6.2 A.c -O3 -S) |
+-------------------------------+--------------------------------+
|main: |main: |
| .cfi_startproc | .cfi_startproc |
|# BB#0: |# BB#0: |
| movl x0(%rip), %eax | |
| leal 1(%rax), %ecx | |
| cmpl $3, %ecx | |
| sbbb %cl, %cl | |
| testl %eax, %eax | |
| setne %al | |
| andb %cl, %al | |
| movzbl %al, %ecx | |
| movl $2, %eax | |
| xorl %edx, %edx | |
| divl %ecx | |
| cmpl $2, %eax | |
| jne .LBB0_2 | |
|# BB#1: | |
| xorl %eax, %eax | xorl %eax, %eax |
| retq | retq |
|.LBB0_2: | |
| pushq %rax | |
|.Ltmp0: |.Ltmp0: |
| .cfi_def_cfa_offset 16 | .size main, .Ltmp0-...|
| callq abort | |
|.Lfunc_end0: | |
| .size main, .Lfunc...| |
| .cfi_endproc | .cfi_endproc |
| | |
| .type x0,@object | .type x0,@object |
| .data | .data |
| .globl x0 | .globl x0 |
| .p2align 2 | .align 4 |
|x0: |x0: |
| .long 1 | .long 1 |
| .size x0, 4 | .size x0, 4 |
| | |
| | |
| .ident "clang versi...| .ident "Ubuntu clang...|
| .section ".no...| .section ".not...|
+-------------------------------+--------------------------------+
using built-in specs.
clang version 4.0.0 (https://github.com/llvm-mirror/clang.git
359c45534e46a8ef263db1a8b855740bbeca6998)
(https://github.com/llvm-mirror/llvm.git
990fea5450379639c1e21f456d44a9e95eabaff3)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/bin
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5.2.1
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.7.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8.5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9.3
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.2.1
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.2.1
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
using built-in specs.
Ubuntu clang version 3.6.2-1 (tags/RELEASE_362/final) (based on LLVM 3.6.2)
Target: x86_64-pc-linux-gnu
Thread model: posix
Found candidate GCC installation: /usr/bin/../lib/gcc/i686-linux-gnu/5.2.1
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/4.7
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/4.7.4
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8.5
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/4.9
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/4.9.3
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/5.2.1
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5.2.1
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.7.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8.5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9.3
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.2.1
Selected GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/5.2.1
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
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