From: Simon Pilgrim <llvm-dev@redking.me.uk>
Date: Mon, 13 Feb 2017 11:52:58 +0000 (+0000)
Subject: [X86][SSE] Create matchVectorShuffleWithUNPCK helper function.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=d9480271fe4af7388f3d0ed7fd56cb06d9326737;p=llvm

[X86][SSE] Create matchVectorShuffleWithUNPCK helper function.

Currently only used by target shuffle combining - will use it for lowering as well in a future patch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@294943 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index bc1b7bc1894..836936e5aa4 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -8222,6 +8222,43 @@ static SDValue lowerVectorShuffleToEXPAND(const SDLoc &DL, MVT VT,
                      ZeroVector);
 }
 
+static bool matchVectorShuffleWithUNPCK(MVT VT, SDValue &V1, SDValue &V2,
+                                        unsigned &UnpackOpcode, bool IsUnary,
+                                        ArrayRef<int> TargetMask) {
+  // Attempt to match the target mask against the unpack lo/hi mask patterns.
+  SmallVector<int, 64> Unpckl, Unpckh;
+  createUnpackShuffleMask(VT, Unpckl, /* Lo = */ true, IsUnary);
+  if (isTargetShuffleEquivalent(TargetMask, Unpckl)) {
+    UnpackOpcode = X86ISD::UNPCKL;
+    return true;
+  }
+
+  createUnpackShuffleMask(VT, Unpckh, /* Lo = */ false, IsUnary);
+  if (isTargetShuffleEquivalent(TargetMask, Unpckh)) {
+    UnpackOpcode = X86ISD::UNPCKH;
+    return true;
+  }
+
+  // If a binary shuffle, commute and try again.
+  if (!IsUnary) {
+    ShuffleVectorSDNode::commuteMask(Unpckl);
+    if (isTargetShuffleEquivalent(TargetMask, Unpckl)) {
+      UnpackOpcode = X86ISD::UNPCKL;
+      std::swap(V1, V2);
+      return true;
+    }
+
+    ShuffleVectorSDNode::commuteMask(Unpckh);
+    if (isTargetShuffleEquivalent(TargetMask, Unpckh)) {
+      UnpackOpcode = X86ISD::UNPCKH;
+      std::swap(V1, V2);
+      return true;
+    }
+  }
+
+  return false;
+}
+
 // X86 has dedicated unpack instructions that can handle specific blend
 // operations: UNPCKH and UNPCKL.
 static SDValue lowerVectorShuffleWithUNPCK(const SDLoc &DL, MVT VT,
@@ -26575,53 +26612,12 @@ static bool matchBinaryVectorShuffle(MVT MaskVT, ArrayRef<int> Mask,
     if (LegalVT.is256BitVector() && !Subtarget.hasAVX2())
       LegalVT = (32 == EltSizeInBits ? MVT::v8f32 : MVT::v4f64);
 
-    SmallVector<int, 64> Unpckl, Unpckh;
-    if (IsUnary) {
-      createUnpackShuffleMask(MaskVT, Unpckl, true, true);
-      if (isTargetShuffleEquivalent(Mask, Unpckl)) {
+    if (matchVectorShuffleWithUNPCK(MaskVT, V1, IsUnary ? V1 : V2, Shuffle,
+                                    IsUnary, Mask)) {
+      if (IsUnary)
         V2 = V1;
-        Shuffle = X86ISD::UNPCKL;
-        ShuffleVT = LegalVT;
-        return true;
-      }
-
-      createUnpackShuffleMask(MaskVT, Unpckh, false, true);
-      if (isTargetShuffleEquivalent(Mask, Unpckh)) {
-        V2 = V1;
-        Shuffle = X86ISD::UNPCKH;
-        ShuffleVT = LegalVT;
-        return true;
-      }
-    } else {
-      createUnpackShuffleMask(MaskVT, Unpckl, true, false);
-      if (isTargetShuffleEquivalent(Mask, Unpckl)) {
-        Shuffle = X86ISD::UNPCKL;
-        ShuffleVT = LegalVT;
-        return true;
-      }
-
-      createUnpackShuffleMask(MaskVT, Unpckh, false, false);
-      if (isTargetShuffleEquivalent(Mask, Unpckh)) {
-        Shuffle = X86ISD::UNPCKH;
-        ShuffleVT = LegalVT;
-        return true;
-      }
-
-      ShuffleVectorSDNode::commuteMask(Unpckl);
-      if (isTargetShuffleEquivalent(Mask, Unpckl)) {
-        std::swap(V1, V2);
-        Shuffle = X86ISD::UNPCKL;
-        ShuffleVT = LegalVT;
-        return true;
-      }
-
-      ShuffleVectorSDNode::commuteMask(Unpckh);
-      if (isTargetShuffleEquivalent(Mask, Unpckh)) {
-        std::swap(V1, V2);
-        Shuffle = X86ISD::UNPCKH;
-        ShuffleVT = LegalVT;
-        return true;
-      }
+      ShuffleVT = LegalVT;
+      return true;
     }
   }