[llvm-bugs] [Bug 41698] New: wrong code with "opt -structurizecfg -simplifycfg -instcombine -jump-threading -structurizecfg -sroa -jump-threading -constprop"

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=41698

            Bug ID: 41698
           Summary: wrong code with "opt -structurizecfg -simplifycfg
                    -instcombine -jump-threading -structurizecfg -sroa
                    -jump-threading -constprop"
           Product: libraries
           Version: 8.0
          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 21863
  --> https://bugs.llvm.org/attachment.cgi?id=21863&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

$opt -structurizecfg -simplifycfg -instcombine -jump-threading -structurizecfg
-sroa -jump-threading -constprop  small.bc -o small-opt.bc

$clang small-opt.bc -o small2.out && ./small2.out
1
0

However, by using lli, the output is correct. 
$lli small-opt.bc 
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;

#define CHAR_BIT 8

#define safe_sub_func_int16_t_s_s(_si1, _si2)                                 
\
  ({                                                                          
\
    int16_t si1 = (_si1);                                                     
\
    int16_t si2 = (_si2);                                                     
\
    (((((int16_t)(si1)) ^ ((int16_t)(si2))) &                                 
\
      (((((int16_t)(si1)) ^                                                   
\
         ((((int16_t)(si1)) ^ ((int16_t)(si2))) &                             
\
          (((int16_t)1) << (sizeof(int16_t) * CHAR_BIT - 1)))) -              
\
        ((int16_t)(si2))) ^                                                   
\
       ((int16_t)(si2)))) < ((int16_t)0))                                     
\
        ? ((int16_t)(si1))                                                    
\
        : (((int16_t)(si1)) - ((int16_t)(si2)));                              
\
  })

struct a {
  int8_t b;
  int32_t c;
  int32_t d;
  uint8_t e;
} f[2], g, t;
struct {
  unsigned b;
} k;
struct {
  int32_t h;
  int16_t j;
} l;
struct {
  struct a c;
} m;
int8_t n;
int32_t *o = &f[0].c;
static struct a p = {9};
struct a q() {
  int8_t r[5][5][7] = {0};
  int32_t **s[10];
  int32_t ***x = &s[2];
  int i;
  for (i = 0; i < 10; i++)
    s[i] = &o;
u:
  if (r[3][3][6] > f[0].d) {
    int32_t v;
    for (; m.c.e; safe_sub_func_int16_t_s_s(l.h, 1))
      if (k.b)
        goto u;
    for (l.j = 5; 0;)
      ;
    if (p.b)
      goto aa;
  } else
    return g;
aa:
  for (; n < 4; n++)
    ***x = 1;
  return t;
}
void main() {
  int i;
  q();
  for (i = 0; i < 2; i++)
    printf("%d\n", f[i].c);
}

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