[llvm-bugs] [Bug 33119] New: wrong code at -Os on x86_64-linux-gnu (in NewGVN with "-mllvm -enable-newgvn")

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=33119

            Bug ID: 33119
           Summary: wrong code at -Os on x86_64-linux-gnu (in NewGVN with
                    "-mllvm -enable-newgvn")
           Product: clang
           Version: trunk
          Hardware: PC
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: -New Bugs
          Assignee: unassignedclangbugs at nondot.org
          Reporter: su at cs.ucdavis.edu
                CC: llvm-bugs at lists.llvm.org

This should be a very recent regression as r303386 doesn't miscompile the code. 

$ clang -v
clang version 5.0.0 (trunk 303495)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/clang-trunk/bin
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5.4.0
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/6.0.0
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/4.7.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8.5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9.3
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.4.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.0.0
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.4.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
$
$ clang -Os small.c; ./a.out
$ /usr/local/clang-r303386/bin/clang -Os -mllvm -enable-newgvn small.c; ./a.out
$
$ clang -Os -mllvm -enable-newgvn small.c
$ ./a.out
Floating point exception (core dumped)
$


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


int a, b, d;
volatile int c;

int main ()
{ 
  int e = 0;
  for (; e < 1; e++)
    {
    L1:
      if (b)
        goto L2;
      int h, i = h = c;
      b = a = ~0;
      if (h)
        goto L1;
      a = i;
    L2:
      c = 1 % ~a;
      d = h;
    }
  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/20170522/7be26131/attachment-0001.html>