Extended Description

The following code is miscompiled by clang-trunk at -O1 and above in 32-bit mode (not 64-bit mode) on x86_64-linux-gnu.

$: clang-trunk -v
clang version 3.8.0 (trunk 256450)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/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
Found candidate GCC installation: /usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.3
Found candidate GCC installation: /usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.7.4
Found candidate GCC installation: /usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.8.2
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 small.c -m32 -O3 ; ./a.out
127
$: clang-trunk small.c -m32 -O2 ; ./a.out
127
$: clang-trunk small.c -m32 -Os ; ./a.out
127
$: clang-trunk small.c -m32 -O1 ; ./a.out
1
$: clang-trunk small.c -m32 -O0 ; ./a.out
1
$: clang-trunk small.c -m64 -O3 ; ./a.out
1
$: cat small.c
int printf(const char*, ...);
char a, b, d;
int c;
int main() {
int e = b++;
c++;
d = a++ == e;
if (c)
printf("%d\n", (int)b);
return 0;
}