Singlepath: crashes on break from nested loop

[Emoun]

llc crashes on an assertion error when trying to compile a program, using singlepath, where an inner loop breaks out of an outer loop:

#include <stdio.h>

volatile int _1 = 1;

int init_func(int outer, int inner){
  int x = 0; 
  #pragma loopbound min 0 max 10
  for(int i = 0; i < outer; i++){
    #pragma loopbound min 0 max 4
    for(int k = 0; k < 5; k++){
      if( (x%100) == inner){
        goto breakLoops; // break out of both loops
      }
      x += _1;
    }
    x += 100;
  }
  breakLoops:
  return x;
}

int main(){
  int outer, inner;
  scanf("%d %d", &outer, &inner);
  printf("%d\n", init_func(outer, inner));
}

Compiling using the command patmos-clang main.c -mpatmos-singlepath=init_func results in the following error:

patmos-llc: /home/s123791/emoun/llvm/lib/Target/Patmos/PatmosSPReduce.cpp:1225: void {anonymous}::PatmosSPReduce::insertDefEdge(llvm::SPScope*, llvm::MachineBasicBlock&, unsigned int, llvm::SPScope::Edge): Assertion `!S->isSubHeader(&Node) || (RI.Scope->getParent() == S)' failed.
0  libLLVMSupport.so       0x00007fb9fe9ec39c llvm::sys::PrintStackTrace(_IO_FILE*) + 53
1  libLLVMSupport.so       0x00007fb9fe9ec62c
2  libLLVMSupport.so       0x00007fb9fe9ebfda
3  libc.so.6               0x00007fb9fe18a4b0
4  libc.so.6               0x00007fb9fe18a428 gsignal + 56
5  libc.so.6               0x00007fb9fe18c02a abort + 362
6  libc.so.6               0x00007fb9fe182bd7
7  libc.so.6               0x00007fb9fe182c82
8  libLLVMPatmosCodeGen.so 0x00007fba016669e7
9  libLLVMPatmosCodeGen.so 0x00007fba01666710
10 libLLVMPatmosCodeGen.so 0x00007fba016651fb
11 libLLVMPatmosCodeGen.so 0x00007fba01663362
12 libLLVMCodeGen.so       0x00007fba000cfd07 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) + 95
13 libLLVMCore.so          0x00007fb9ff258946 llvm::FPPassManager::runOnFunction(llvm::Function&) + 330
14 libLLVMCore.so          0x00007fb9ff258abc llvm::FPPassManager::runOnModule(llvm::Module&) + 120
15 libLLVMCore.so          0x00007fb9ff258dbc
16 libLLVMCore.so          0x00007fb9ff25938f llvm::legacy::PassManagerImpl::run(llvm::Module&) + 267
17 libLLVMCore.so          0x00007fb9ff259569 llvm::legacy::PassManager::run(llvm::Module&) + 39
18 patmos-llc              0x000000000040ce99
19 patmos-llc              0x000000000040beac
20 libc.so.6               0x00007fb9fe175830 __libc_start_main + 240
21 patmos-llc              0x000000000040b779
Stack dump:
0.      Program arguments: /home/s123791/emoun/local/bin/patmos-llc -O0 -mforce-block-labels -disable-separate-nested-loops -mpatmos-singlepath=init_func -filetype=obj -o /tmp/a-104e35.bc.o /tmp/a-8e960e.bc
1.      Running pass 'Function Pass Manager' on module '/tmp/a-8e960e.bc'.
2.      Running pass 'Patmos Single-Path Reducer' on function '@init_func'
patmos-clang-3.4: error: unable to execute command: Aborted (core dumped)
patmos-clang-3.4: error: link  via llvm-link, opt and llc command failed due to signal (use -v to see invocation)

[Emoun]

I tried manually executing all compilation steps. I.e. use patmos-clang to compile to bitcode and patmos-llc to compile to machine code. When llc is given the -O0 flag, the above assertion error is thrown. But if it is given -O1, -O2, or -O3 the compilation will succeed, but the execution will return the wrong result. E.g. when given the input 10 55 it returns 55 instead of 1050.

[Emoun]

The same problem is seen when goto breakLoops is replaced by a return x. (the programs are equivalent)

[Emoun]

Trying to continue an outer loop from an inner nested loop also given error. Take the following program, where we emulate continue using a goto:

#include <stdio.h>

int init_func(int pre, int inner, int post){
  int x = 0, y = 0, z = 0;
  outer_loop:
  #pragma loopbound min 0 max 9
  while(x < pre){
    x++;
    #pragma loopbound min 0 max 9
    for(int i = 0; i < inner; i++){
      y++;
      if(z >= post){
        goto outer_loop; //Continue outer loop
      }
    }
    z++;
  }
  return (x*10000) + (y*10) + z;
}

int main(){
  int pre, inner, post;
  scanf("%d %d %d", &pre, &inner, &post);
  printf("%d\n", init_func(pre, inner, post));
}

It compiles successfully and when run with the input 1 9 1 it correctly outputs 10091. But, given the input 1 10 1 we would expect the output 10101 but get 10000. I.e. only when the second input integer is at the loop bound (10) does it execute incorrectly.