https://bugs.llvm.org/show_bug.cgi?id=41703
Bug ID: 41703
Summary: wrong code with "opt -loop-extract-single -mergereturn
-structurizecfg -ipsccp -loop-simplify"
Product: libraries
Version: 8.0
Hardware: PC
OS: Linux
Status: NEW
Severity: enhancement
Priority: P
Component: Scalar Optimizations
Assignee: unassignedb...@nondot.org
Reporter: csz...@163.com
CC: llvm-bugs@lists.llvm.org
Created attachment 21872
--> https://bugs.llvm.org/attachment.cgi?id=21872&action=edit
.bc file of the source code
$clang -v
clang version 8.0.0 (tags/RELEASE_800/final)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir:
/home/jack-zhou/clang+llvm-8.0.0-x86_64-linux-gnu-ubuntu-18.04/bin
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.4.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.4.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
$clang -O3 -c -emit-llvm -mllvm -disable-llvm-optzns small.c -o small.bc
$ clang small.bc -o small1.out && ./small1.out
0
0
0
0
3
0
0
0
$opt -loop-extract-single -mergereturn -structurizecfg -ipsccp -loop-simplify
small.bc -o small-opt.bc
clang small-opt.bc -o small2.out && ./small2.out
0
0
0
0
0
0
0
0
---------------------------------------------
#include <stdio.h>
typedef signed char int8_t;
typedef short int int16_t;
typedef int int32_t;
typedef long int int64_t;
/* Unsigned. */
typedef unsigned char uint8_t;
typedef unsigned short int uint16_t;
typedef unsigned int uint32_t;
typedef unsigned long int uint64_t;
int32_t a[8];
int32_t *b = &a[4];
uint8_t c = 3;
int32_t **d = &b;
uint8_t e;
uint16_t f(g) {
uint16_t h = 2;
int32_t ***m = &d;
for (; h; ++h) {
for (; e;) {
int64_t j = 0;
if (j)
break;
}
***m = c;
}
return 0;
}
void main() {
int i, k = 0;
int16_t l = 4;
f(l);
for (i = 0; i < 8; i++)
printf("%d\n",a[i]);
}
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