[X86][SSE] Match all-of bool scalar reductions into a bitcast/movmsk + cmp.

Same as what we do for vector reductions in combineHorizontalPredicateResult, use movmsk+cmp for scalar (and(extract(x,0),extract(x,1)) reduction patterns. 

llvm-svn: 361052

1 files changed, 18 insertions, 0 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index a52d0faa35b..743e23977e5 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -37841,6 +37841,24 @@ static SDValue combineAnd(SDNode *N, SelectionDAG &DAG,
   if (SDValue V = combineParity(N, DAG, Subtarget))
     return V;
 
+  // Match all-of bool scalar reductions into a bitcast/movmsk + cmp.
+  // TODO: Support multiple SrcOps.
+  if (VT == MVT::i1) {
+    SmallVector<SDValue, 2> SrcOps;
+    if (matchBitOpReduction(SDValue(N, 0), ISD::AND, SrcOps) &&
+        SrcOps.size() == 1) {
+      SDLoc dl(N);
+      unsigned NumElts = SrcOps[0].getValueType().getVectorNumElements();
+      EVT MaskVT = EVT::getIntegerVT(*DAG.getContext(), NumElts);
+      SDValue Mask = combineBitcastvxi1(DAG, MaskVT, SrcOps[0], dl, Subtarget);
+      if (Mask) {
+        APInt AllBits = APInt::getAllOnesValue(NumElts);
+        return DAG.getSetCC(dl, MVT::i1, Mask,
+                            DAG.getConstant(AllBits, dl, MaskVT), ISD::SETEQ);
+      }
+    }
+  }
+
   if (DCI.isBeforeLegalizeOps())
     return SDValue();