https://llvm.org/bugs/show_bug.cgi?id=27624
Bug ID: 27624
Summary: wrong code at -O3 with -g enabled in 32-bit mode on
x86_64-linux-gnu
Product: clang
Version: trunk
Hardware: PC
OS: All
Status: NEW
Severity: normal
Priority: P
Component: -New Bugs
Assignee: unassignedclangb...@nondot.org
Reporter: s...@cs.ucdavis.edu
CC: llvm-bugs@lists.llvm.org
Classification: Unclassified
The following code is miscompiled by the current trunk at -O3 with debugging
enabled (-g) in the 32-bit mode (but not in the 64-bit mode) on
x86_64-linux-gnu.
This is a regression from 3.8.x.
$ clang-trunk -v
clang version 3.9.0 (trunk 268365)
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/5.3.0
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/4.8.5
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/5.3.0
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 -O3 small.c; ./a.out
0
$ clang-trunk -m32 -O2 -g small.c; ./a.out
0
$ clang-3.8 -m32 -O3 -g small.c; ./a.out
0
$
$ clang-trunk -m32 -O3 -g small.c; ./a.out
1
$
-----------------------------------------------------------
int printf (const char *, ...);
int a, b[1], c, d, e, f, g, h, i, j[4843583], k, l, m, n;
unsigned o;
unsigned long long p;
char q;
short r;
void
fn1 (int p1)
{
o = 1 & b[o ^ p1];
}
void
fn2 (long long p1)
{
fn1 (p1 >> 56);
}
void
fn3 (int p1)
{
int s = 0;
r = s = -p1;
h = s >= p1;
if (q)
c = 1;
}
static unsigned
fn4 ()
{
for (i = 0;; i++)
for (; e < 2;)
{
for (d = 1; d; d--)
for (g = 0; g;)
if (q)
l = 0;
for (; m; m++)
for (k = 0; k < 10; k++)
fn2 (j[4843582 + m * k]);
if (q)
break;
n = a + 1;
if (n)
return 1;
for (; f; f++)
for (; q < 5; q++)
;
}
}
static unsigned
fn5 ()
{
fn4 ();
return 0;
}
int
main ()
{
fn3 (p <= (fn5 (), 1));
printf ("%d\n", c);
return 0;
}
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