$ gcc-4.2.0 -v
Using built-in specs.
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc-4.2.0/configure --enable-languages=c,c++,objc,obj-c++
--program-suffix=-4.2.0
Thread model: posix
gcc version 4.2.0
$ gcc-4.2.0 divop.c -o divop
$ ./divop
3CBA83
$ gcc-4.2.0 -ftree-vectorize -O2 divop.c -o divop
$ ./divop
3CBA83
$ gcc-4.2.0 -ftree-vectorize -O2 -march=opteron divop.c -o divop
$ ./divop
3CBA83
$ gcc-4.2.0 -ftree-vectorize -O2 -march=nocona divop.c -o divop
$ ./divop
2B672F
This also affects GCC 4.1.1, I have not checked 4.1.2 or the 4.3 snapshots. In
addition to -march=nocona it requires -O1/-O2/-O3 (-Os does not trigger it
under 4.2.0, though it _does_ in 4.1.1).
--
Summary: Miscompiles valid code with -ftree-vectorize and -
march=nocona
Product: gcc
Version: 4.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: lloyd at randombit dot net
GCC build triplet: x86_64-unknown-linux-gnu
GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: x86_64-unknown-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31966
