[llvm-bugs] [Bug 41633] New: wrong code with "opt -simplifycfg -jump-threading -globalopt -newgvn -simple-loop-unswitch -structurizecfg -ipsccp -instcombine"

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=41633

            Bug ID: 41633
           Summary: wrong code with "opt -simplifycfg -jump-threading
                    -globalopt -newgvn -simple-loop-unswitch
                    -structurizecfg -ipsccp -instcombine"
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Scalar Optimizations
          Assignee: unassignedbugs at nondot.org
          Reporter: cszide at 163.com
                CC: llvm-bugs at lists.llvm.org

Created attachment 21833
  --> https://bugs.llvm.org/attachment.cgi?id=21833&action=edit
.bc file of the source code

$clang -v
clang version 9.0.0 (trunk 355281)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/jack-zhou/Documents/llvm/llvm_truck/llvm/build4/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/7.3.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.3.0
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 small.out && ./small.out
0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 
65535 0 0 0 0 0 0 0 0

$opt -simplifycfg -jump-threading -globalopt -newgvn -simple-loop-unswitch
-structurizecfg -ipsccp -instcombine small.bc -o small-opt1.bc

$clang small-opt1.bc -o small1.out && ./small1.out
0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0

$opt -simplifycfg -jump-threading -globalopt -newgvn -simple-loop-unswitch
-structurizecfg -ipsccp  small.bc -o small-opt2.bc

$clang small-opt2.bc -o small2.out && ./small2.out
0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 
3723 0 0 0 0 0 0 0 0

$opt -simplifycfg -jump-threading -globalopt -newgvn -simple-loop-unswitch
-structurizecfg  small.bc -o small-opt3.bc

$clang small-opt3.bc -o small3.out && ./small3.out
0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 
52607 0 0 0 0 0 0 0 0

----------------------------------------------------
#include<stdio.h>
//------------------------
typedef signed char             int8_t;
typedef int                     int32_t;
/* Unsigned.  */
typedef unsigned char           uint8_t;
typedef unsigned short int      uint16_t;
typedef unsigned int            uint32_t;

uint32_t a, d;
uint16_t b[5][9];
static uint16_t *c = &b[4][0];
uint8_t e() {
  int f = 0;
  for (; f < 2; f++)
  g:;
    if (*c) {
      int8_t h;
      for (; d; d = 9) {
        int32_t i;
        if (a)
          goto g;
      }
    }
  --*c;
  return 0;
}
void main() {
  int f, j, k = 0;
  e();
  for (f = 0; f < 5; f++){
    for (j = 0; j < 9; j++){
      printf("%d ", b[f][j]);
    }
    printf("\n");
  }

}

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