PR target/94680: Clear upper bits of V2DF using movq (like V2DI).
This simple i386 patch unblocks a more significant change. The testcase
gcc.target/i386/sse2-pr94680.c isn't quite testing what's intended, and
alas the fix for PR target/94680 doesn't (yet) handle V2DF mode.
For the first test from sse2-pr94680.c, below
v2df foo_v2df (v2df x) {
return __builtin_shuffle (x, (v2df) { 0, 0 }, (v2di) { 0, 2 });
}
GCC on x86_64-pc-linux-gnu with -O2 currently generates:
movhpd .LC0(%rip), %xmm0
ret
.LC0:
.long 0
.long 0
which passes the test as it contains a mov insn and no xor.
Alas reading a zero from the constant pool isn't quite the
desired implementation. With this patch we now generate:
movq %xmm0, %xmm0
ret
The same code as we generate for V2DI, and add a stricter
test case. This implementation generalizes the sse2_movq128
to V2DI and V2DF modes using a VI8F_128 mode iterator and
renames it *sse2_movq128_<mode>. A new define_expand is
introduced for sse2_movq128 so that the exisiting builtin
interface (CODE_FOR_sse2_movq128) remains the same.
2022-03-16 Roger Sayle <roger@nextmovesoftware.com>
gcc/ChangeLog
PR target/94680
* config/i386/sse.md (sse2_movq128): New define_expand to
preserve previous named instruction.
(*sse2_movq128_<mode>): Renamed from sse2_movq128, and
generalized to VI8F_128 (both V2DI and V2DF).
gcc/testsuite/ChangeLog
PR target/94680
* gcc.target/i386/sse2-pr94680-2.c: New stricter V2DF test case.