X86: Custom lower <2 x i64> eq and ne when SSE41 is not available.
pcmpeqd, pshufd, pshufd, pand is cheaper than unpack + cmpq, sbbq, cmpq, sbbq + pack.
Small speedup on loop-vectorized viterbi (-march=core2).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171063 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 5f7f915..a173712 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -9171,8 +9171,30 @@
if (VT == MVT::v2i64) {
if (Opc == X86ISD::PCMPGT && !Subtarget->hasSSE42())
return SDValue();
- if (Opc == X86ISD::PCMPEQ && !Subtarget->hasSSE41())
- return SDValue();
+ if (Opc == X86ISD::PCMPEQ && !Subtarget->hasSSE41()) {
+ // If pcmpeqq is missing but pcmpeqd is available synthesize pcmpeqq with
+ // pcmpeqd + 2 shuffles + pand.
+ assert(Subtarget->hasSSE2() && !FlipSigns && "Don't know how to lower!");
+
+ // First cast everything to the right type,
+ Op0 = DAG.getNode(ISD::BITCAST, dl, MVT::v4i32, Op0);
+ Op1 = DAG.getNode(ISD::BITCAST, dl, MVT::v4i32, Op1);
+
+ // Do the compare.
+ SDValue Result = DAG.getNode(Opc, dl, MVT::v4i32, Op0, Op1);
+
+ // Make sure the lower and upper halves are both all-ones.
+ const int Mask1[] = { 0, 0, 2, 2 };
+ SDValue S1 = DAG.getVectorShuffle(MVT::v4i32, dl, Result, Result, Mask1);
+ const int Mask2[] = { 1, 1, 3, 3 };
+ SDValue S2 = DAG.getVectorShuffle(MVT::v4i32, dl, Result, Result, Mask2);
+ Result = DAG.getNode(ISD::AND, dl, MVT::v4i32, S1, S2);
+
+ if (Invert)
+ Result = DAG.getNOT(dl, Result, MVT::v4i32);
+
+ return DAG.getNode(ISD::BITCAST, dl, VT, Result);
+ }
}
// Since SSE has no unsigned integer comparisons, we need to flip the sign