[llvm-bugs] [Bug 42444] New: loop-reroll makes function broken with "opt -sroa -loop-idiom -jump-threading -lcssa -loop-reroll"

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=42444

            Bug ID: 42444
           Summary: loop-reroll makes function broken with "opt -sroa
                    -loop-idiom -jump-threading -lcssa -loop-reroll"
           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 22163
  --> https://bugs.llvm.org/attachment.cgi?id=22163&action=edit
.bc file of the source code

$clang -v
clang version 9.0.0 (trunk 363125)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build1/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 -femit-all-decls -mllvm -disable-llvm-optzns small.c

$opt -sroa -loop-idiom -jump-threading -lcssa -loop-reroll small.bc -o
small-opt.bc
PHI nodes must have at least one entry.  If the block is dead, the PHI should
be removed!
  %i.sroa.3.3.lcssa18 = phi i32**** 
in function c
LLVM ERROR: Broken function found, compilation aborted!

without loop-reroll pass, opt works fine.
$opt -sroa -loop-idiom -jump-threading -lcssa small.bc -o small-opt.bc

-------------------------------------------
long a;
int ***b;
void c() {
d:
  for (;;) {
    long e;
    for (; 0;)
      for (;;) {
        unsigned *f;
        unsigned **g = &f;
        unsigned ***h = &g;
        unsigned ****i[10][7] = {0, 0, &h};
        int ****j[] = {&b, &b};
        for (; a;)
          goto d;
      }
  }
}

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