[llvm-bugs] [Bug 41697] New: Broken function found with "opt -newgvn -loop-unswitch -licm -loop-extract-single"

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=41697

            Bug ID: 41697
           Summary: Broken function found with "opt -newgvn -loop-unswitch
                     -licm -loop-extract-single"
           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 21862
  --> https://bugs.llvm.org/attachment.cgi?id=21862&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

$opt -newgvn -loop-unswitch -licm -loop-extract-single  small.bc -o
small-opt.bc
Instruction does not dominate all uses!
  %24 = alloca i32, align 4
  %17 = bitcast i32* %24 to i8*
Instruction does not dominate all uses!
  %22 = alloca i64, align 8
  %18 = bitcast i64* %22 to i8*
Instruction does not dominate all uses!
  %26 = alloca i64, align 8
  %19 = bitcast i64* %26 to i8*
Instruction does not dominate all uses!
  %24 = alloca i32, align 4
  %20 = bitcast i32* %24 to i8*
Instruction does not dominate all uses!
  %22 = alloca i64, align 8
  %21 = bitcast i64* %22 to i8*
Instruction does not dominate all uses!
  %24 = alloca i32, align 4
  %22 = bitcast i32* %24 to i8*
Instruction does not dominate all uses!
  %22 = alloca i64, align 8
  %23 = bitcast i64* %22 to i8*
Instruction does not dominate all uses!
  %26 = alloca i64, align 8
  %26 = bitcast i64* %26 to i8*
Instruction does not dominate all uses!
  %24 = alloca i32, align 4
  %27 = bitcast i32* %24 to i8*
Instruction does not dominate all uses!
  %22 = alloca i64, align 8
  %28 = bitcast i64* %22 to i8*
Instruction does not dominate all uses!
  %24 = alloca i32, align 4
  %29 = bitcast i32* %24 to i8*
Instruction does not dominate all uses!
  %22 = alloca i64, align 8
  %30 = bitcast i64* %22 to i8*
Instruction does not dominate all uses!
  %26 = alloca i64, align 8
  %31 = bitcast i64* %26 to i8*
Instruction does not dominate all uses!
  %24 = alloca i32, align 4
  %32 = bitcast i32* %24 to i8*
Instruction does not dominate all uses!
  %22 = alloca i64, align 8
  %33 = bitcast i64* %22 to i8*
Instruction does not dominate all uses!
  %24 = alloca i32, align 4
  %34 = bitcast i32* %24 to i8*
Instruction does not dominate all uses!
  %22 = alloca i64, align 8
  %35 = bitcast i64* %22 to i8*
in function e
LLVM ERROR: Broken function found, compilation aborted!

By using godbolt, it shows that LLVM 6/7/trunk version also have this problem.

--------------------------------------
union a {
  unsigned int b;
};
int c;
union a d;

unsigned int e(unsigned short int i, union a m, int *j, int f) {
k:
  for (; d.b;)
    for (; f <= 2;) {
      long int l;
      for (; 2;) {
        int n;
        unsigned long int o;
        if (f)
          goto k;
      }
    }
}
int g() { 
  int *n = &c;
  e(0, d, n, c); 
}

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