[llvm-bugs] [Bug 44344] New: Machine outliner runs out of stack space analyzing large sequences

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=44344

            Bug ID: 44344
           Summary: Machine outliner runs out of stack space analyzing
                    large sequences
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P
         Component: Common Code Generator Code
          Assignee: unassignedbugs at nondot.org
          Reporter: lewis.revill at embecosm.com
                CC: llvm-bugs at lists.llvm.org

Discussed in https://reviews.llvm.org/D66210, this bug occurs when running the
following testcase with machine outlining enabled for RISC-V (command used to
run: 'riscv32-unknown-elf-clang -O -c -mllvm -enable-machine-outliner'):


/* PR rtl-optimization/48141 */
/* { dg-do compile } */
/* { dg-options "-O" } */

#define A i = 0;
#define B A A A A A A A A A A
#define C B B B B B B B B B B
#define D C C C C C C C C C C
#define E D D D D D D D D D D

int
foo (void)
{
  volatile int i = 0;
  E E E E E E E E E E E
  return 0;
}

This fails with a segmentation fault from within the function
'setSuffixIndices'. Valgrind reports that after a large amount of recursive
calls of this function the program runs out of stack memory.

I have attempted to reproduce this bug for X86 or AArch64 but due to some of
the target-specific restrictions on what instructions can be outlined I found
it intractable to create a simple testcase. However by temporarily modifying
those restrictions within the compiler I can indeed reproduce this segmentation
fault.

-- 
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20191219/4030f803/attachment.html>