[llvm-bugs] [Bug 24992] New: wrong code at -O3 on x86_64-linux-gnu (in 32-bit mode)

[via llvm-bugs]

https://llvm.org/bugs/show_bug.cgi?id=24992

            Bug ID: 24992
           Summary: wrong code at -O3 on x86_64-linux-gnu (in 32-bit mode)
           Product: clang
           Version: trunk
          Hardware: PC
                OS: All
            Status: NEW
          Severity: normal
          Priority: P
         Component: -New Bugs
          Assignee: unassignedclangbugs at nondot.org
          Reporter: su at cs.ucdavis.edu
                CC: llvm-bugs at lists.llvm.org
    Classification: Unclassified

The following code is miscompiled by the current clang trunk on
x86_64-linux-gnu at -O3 in 32-bit mode (but not in 64-bit mode).

This is a regression from 3.7.x. 

Possibly related to PR 24991? 

$ clang-trunk -v
clang version 3.8.0 (trunk 248820)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/tools/bin
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.9.2
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5.1.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4.7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.6.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.7.3
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8.2
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9.2
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.1.0
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
$ 
$ clang-trunk -m32 -O2 small.c; ./a.out
$ clang-trunk -m64 -O3 small.c; ./a.out
$ clang-3.7.0 -m32 -O3 small.c; ./a.out
$ 
$ clang-trunk -m32 -O3 small.c
$ ./a.out
Aborted
$ 


---------------------------------


int a, d, e, f, g;
char b;
unsigned int c;

int
fn1 (int p1)
{
  return p1;
}

int
main ()
{
  c--;
  a = (b-- == 0) & e++;
  f = g > 0;
  for (;;)
    if (fn1 (c > 0))
      {
    if (e)
      break;
    d = 0;
      }

  if (b != -1) 
    __builtin_abort (); 

  return 0;
}

-- 
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/20150929/63cce1d5/attachment.html>