[llvm-bugs] [Bug 26025] New: wrong code at -Os and above on x86_64-linux-gnu in 32-bit mode

[via llvm-bugs]

https://llvm.org/bugs/show_bug.cgi?id=26025

            Bug ID: 26025
           Summary: wrong code at -Os and above 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 -Os and above in the 32-bit mode (but not in the 64-bit
mode). 

This is a regression from 3.7.x.


$ clang-trunk -v
clang version 3.8.0 (trunk 256763)
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/4.9.3
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5.2.1
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/4.8.4
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/5.2.1
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 -O1 small.c; ./a.out
$ clang-trunk -m64 -Os small.c; ./a.out
$ clang-3.7.0 -m32 -Os small.c; ./a.out
$
$ clang-trunk -m32 -Os small.c
$ ./a.out
Aborted (core dumped)
$ clang-trunk -m32 -O2 small.c
$ ./a.out
Aborted (core dumped)
$ clang-trunk -m32 -O3 small.c
$ ./a.out
Aborted (core dumped)
$

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


unsigned int c, f;
volatile char b, i;
unsigned long long d;

int
fn1 (int p1, int p2)
{ 
  return p2 ? p2 : p1;
}

short
fn2 (int p1, int p2)
{ 
  return p1 / p2;
}

char
fn3 (int p1)
{ 
  return 0;
}

int
main ()
{ 
  i = fn1 (c, fn2 ((f <= d) <= fn3 (b), -3));

  if (i)
    __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/20160105/e64c6485/attachment.html>