[llvm-bugs] [Bug 41700] New: wrong code with "opt -ipsccp -deadargelim -jump-threading -reg2mem -structurizecfg -jump-threading -newgvn -instcombine -mem2reg -ipsccp"

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=41700

            Bug ID: 41700
           Summary: wrong code with "opt -ipsccp -deadargelim
                    -jump-threading -reg2mem -structurizecfg
                    -jump-threading -newgvn -instcombine -mem2reg -ipsccp"
           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 21868
  --> https://bugs.llvm.org/attachment.cgi?id=21868&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
4

$opt -ipsccp -deadargelim -jump-threading -reg2mem -structurizecfg
-jump-threading -newgvn -instcombine -mem2reg -ipsccp  small.bc -o small-opt.bc

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

static int64_t(safe_add_func_int64_t_s_s)(int64_t si1, int64_t si2) {
  return (((si1 > 0) && (si2 > 0) && (si1 > ((9223372036854775807L) - si2))) ||
          ((si1 < 0) && (si2 < 0) &&
           (si1 < ((-9223372036854775807L - 1) - si2))))
             ? ((si1))
             : (si1 + si2);
}

static int16_t(safe_sub_func_int16_t_s_s)(int16_t si1, int16_t si2) {
  return (si1 - si2);
}

struct {
  int64_t a;
} b, d;
int32_t c, e;
int32_t *f = &e;
int64_t *g = &b.a;
static int16_t h(uint16_t, int8_t, int8_t, int32_t, uint32_t);
int8_t i() {
  int32_t k[] = {4};
  uint32_t j = 3;
  int32_t m = *g = safe_sub_func_int16_t_s_s(k[0], h(0, 0, j, *f, 0));
  return m;
}
int16_t h(uint16_t l, int8_t o, int8_t n, int32_t q, uint32_t p) {
  for (; c <= 7; c = safe_add_func_int64_t_s_s(c, 7))
    for (; o; o = 3)
      for (; d.a;)
        return 0;
  return q;
}
void main() {
  i();
  printf("%ld\n", b.a);
}

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