[X86][SSE] Add support for combining target shuffles to binary BLEND

We already had support for 1-input BLEND with zero - this adds support for 2-input BLEND as well.

llvm-svn: 283040

1 files changed, 30 insertions, 4 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 6c8def1c397..cd1ff4de70f 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -25160,7 +25160,7 @@ static bool matchBinaryPermuteVectorShuffle(MVT MaskVT, ArrayRef<int> Mask,
     }
   }
 
-  // Attempt to blend with zero.
+  // Attempt to combine to X86ISD::BLENDI.
   if (NumMaskElts <= 8 && ((Subtarget.hasSSE41() && MaskVT.is128BitVector()) ||
                            (Subtarget.hasAVX() && MaskVT.is256BitVector()))) {
     // Determine a type compatible with X86ISD::BLENDI.
@@ -25180,12 +25180,13 @@ static bool matchBinaryPermuteVectorShuffle(MVT MaskVT, ArrayRef<int> Mask,
         BlendVT = MVT::v8f32;
     }
 
+    unsigned BlendSize = BlendVT.getVectorNumElements();
+    unsigned MaskRatio = BlendSize / NumMaskElts;
+
+    // Can we blend with zero?
     if (isSequentialOrUndefOrZeroInRange(Mask, /*Pos*/ 0, /*Size*/ NumMaskElts,
                                          /*Low*/ 0) &&
         NumMaskElts <= BlendVT.getVectorNumElements()) {
-      unsigned BlendSize = BlendVT.getVectorNumElements();
-      unsigned MaskRatio = BlendSize / NumMaskElts;
-
       PermuteImm = 0;
       for (unsigned i = 0; i != BlendSize; ++i)
         if (Mask[i / MaskRatio] < 0)
@@ -25196,6 +25197,31 @@ static bool matchBinaryPermuteVectorShuffle(MVT MaskVT, ArrayRef<int> Mask,
       ShuffleVT = BlendVT;
       return true;
     }
+
+    // Attempt to match as a binary blend.
+    if (NumMaskElts <= BlendVT.getVectorNumElements()) {
+      bool MatchBlend = true;
+      for (int i = 0; i != NumMaskElts; ++i) {
+        int M = Mask[i];
+        if (M == SM_SentinelUndef)
+          continue;
+        else if (M == SM_SentinelZero)
+          MatchBlend = false;
+        else if ((M != i) && (M != (i + NumMaskElts)))
+          MatchBlend = false;
+      }
+
+      if (MatchBlend) {
+        PermuteImm = 0;
+        for (unsigned i = 0; i != BlendSize; ++i)
+          if ((int)NumMaskElts <= Mask[i / MaskRatio])
+            PermuteImm |= 1u << i;
+
+        Shuffle = X86ISD::BLENDI;
+        ShuffleVT = BlendVT;
+        return true;
+      }
+    }
   }
 
   // Attempt to combine to INSERTPS.