[DAGCombiner] teach how to simplify xor/and/or nodes according to the following rules:

 1)  (AND (shuf (A, C, Mask), shuf (B, C, Mask)) -> shuf (AND (A, B), C, Mask)
 2)  (OR  (shuf (A, C, Mask), shuf (B, C, Mask)) -> shuf (OR  (A, B), C, Mask)
 3)  (XOR (shuf (A, C, Mask), shuf (B, C, Mask)) -> shuf (XOR (A, B), V_0, Mask)

 4)  (AND (shuf (C, A, Mask), shuf (C, B, Mask)) -> shuf (C, AND (A, B), Mask)
 5)  (OR  (shuf (C, A, Mask), shuf (C, B, Mask)) -> shuf (C, OR  (A, B), Mask)
 6)  (XOR (shuf (C, A, Mask), shuf (C, B, Mask)) -> shuf (V_0, XOR (A, B), Mask)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204160 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index c45d6a1a79065a9ade6fc13dc70b88fc2f3aa555..2b2bbf9e29646ab1b02e09d0a6d9a881ed0d2137 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -2518,35 +2518,66 @@ SDValue DAGCombiner::SimplifyBinOpWithSameOpcodeHands(SDNode *N) {
   // The type-legalizer generates this pattern when loading illegal
   // vector types from memory. In many cases this allows additional shuffle
   // optimizations.
-  if (N0.getOpcode() == ISD::VECTOR_SHUFFLE && Level < AfterLegalizeDAG &&
-      N0.getOperand(1).getOpcode() == ISD::UNDEF &&
-      N1.getOperand(1).getOpcode() == ISD::UNDEF) {
+  // There are other cases where moving the shuffle after the xor/and/or
+  // is profitable even if shuffles don't perform a swizzle.
+  // If both shuffles use the same mask, and both shuffles have the same first
+  // or second operand, then it might still be profitable to move the shuffle
+  // after the xor/and/or operation.
+  if (N0.getOpcode() == ISD::VECTOR_SHUFFLE && Level < AfterLegalizeDAG) {
     ShuffleVectorSDNode *SVN0 = cast<ShuffleVectorSDNode>(N0);
     ShuffleVectorSDNode *SVN1 = cast<ShuffleVectorSDNode>(N1);
 
-    assert(N0.getOperand(0).getValueType() == N1.getOperand(1).getValueType() &&
+    assert(N0.getOperand(0).getValueType() == N1.getOperand(0).getValueType() &&
            "Inputs to shuffles are not the same type");
-
-    unsigned NumElts = VT.getVectorNumElements();
-
+ 
     // Check that both shuffles use the same mask. The masks are known to be of
     // the same length because the result vector type is the same.
-    bool SameMask = true;
-    for (unsigned i = 0; i != NumElts; ++i) {
-      int Idx0 = SVN0->getMaskElt(i);
-      int Idx1 = SVN1->getMaskElt(i);
-      if (Idx0 != Idx1) {
-        SameMask = false;
-        break;
+    // Check also that shuffles have only one use to avoid introducing extra
+    // instructions.
+    if (SVN0->hasOneUse() && SVN1->hasOneUse() &&
+        SVN0->getMask().equals(SVN1->getMask())) {
+      SDValue ShOp = N0->getOperand(1);
+
+      // Don't try to fold this node if it requires introducing a
+      // build vector of all zeros that might be illegal at this stage.
+      if (N->getOpcode() == ISD::XOR && ShOp.getOpcode() != ISD::UNDEF) {
+        if (!LegalTypes)
+          ShOp = DAG.getConstant(0, VT);
+        else
+          ShOp = SDValue();
       }
-    }
 
-    if (SameMask) {
-      SDValue Op = DAG.getNode(N->getOpcode(), SDLoc(N), VT,
-                               N0.getOperand(0), N1.getOperand(0));
-      AddToWorkList(Op.getNode());
-      return DAG.getVectorShuffle(VT, SDLoc(N), Op,
-                                  DAG.getUNDEF(VT), &SVN0->getMask()[0]);
+      // (AND (shuf (A, C), shuf (B, C)) -> shuf (AND (A, B), C)
+      // (OR  (shuf (A, C), shuf (B, C)) -> shuf (OR  (A, B), C)
+      // (XOR (shuf (A, C), shuf (B, C)) -> shuf (XOR (A, B), V_0)
+      if (N0.getOperand(1) == N1.getOperand(1) && ShOp.getNode()) {
+        SDValue NewNode = DAG.getNode(N->getOpcode(), SDLoc(N), VT,
+                                      N0->getOperand(0), N1->getOperand(0));
+        AddToWorkList(NewNode.getNode());
+        return DAG.getVectorShuffle(VT, SDLoc(N), NewNode, ShOp,
+                                    &SVN0->getMask()[0]);
+      }
+
+      // Don't try to fold this node if it requires introducing a
+      // build vector of all zeros that might be illegal at this stage.
+      ShOp = N0->getOperand(0);
+      if (N->getOpcode() == ISD::XOR && ShOp.getOpcode() != ISD::UNDEF) {
+        if (!LegalTypes)
+          ShOp = DAG.getConstant(0, VT);
+        else
+          ShOp = SDValue();
+      }
+
+      // (AND (shuf (C, A), shuf (C, B)) -> shuf (C, AND (A, B))
+      // (OR  (shuf (C, A), shuf (C, B)) -> shuf (C, OR  (A, B))
+      // (XOR (shuf (C, A), shuf (C, B)) -> shuf (V_0, XOR (A, B))
+      if (N0->getOperand(0) == N1->getOperand(0) && ShOp.getNode()) {
+        SDValue NewNode = DAG.getNode(N->getOpcode(), SDLoc(N), VT,
+                                      N0->getOperand(1), N1->getOperand(1));
+        AddToWorkList(NewNode.getNode());
+        return DAG.getVectorShuffle(VT, SDLoc(N), ShOp, NewNode,
+                                    &SVN0->getMask()[0]);
+      }
     }
   }
 

diff --git a/test/CodeGen/X86/combine-or.ll b/test/CodeGen/X86/combine-or.ll
index 60b6d756165cf4110eb0fc305864dd4b1374fb35..c1ce53334ec6c4cfdb7f20434954d98e9972af3a 100644 (file)
--- a/test/CodeGen/X86/combine-or.ll
+++ b/test/CodeGen/X86/combine-or.ll
@@ -251,6 +251,7 @@ define <2 x i64> @test20(<2 x i64> %a, <2 x i64> %b) {
 ; CHECK-LABEL: test20
 ; CHECK-NOT: xorps
 ; CHECK: orps
+; CHECK-NEXT: movq
 ; CHECK-NEXT: ret
 
 
@@ -262,6 +263,7 @@ define <2 x i64> @test21(<2 x i64> %a, <2 x i64> %b) {
 }
 ; CHECK-LABEL: test21
 ; CHECK: por
+; CHECK-NEXT: pslldq
 ; CHECK-NEXT: ret
 
 

diff --git a/test/CodeGen/X86/combine-vec-shuffle.ll b/test/CodeGen/X86/combine-vec-shuffle.ll
new file mode 100644 (file)
index 0000000..9e6ab89
--- /dev/null
+++ b/test/CodeGen/X86/combine-vec-shuffle.ll
@@ -0,0 +1,253 @@
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=corei7 | FileCheck %s
+
+; Verify that the DAGCombiner correctly folds according to the following rules:
+
+; fold (AND (shuf (A, C), shuf (B, C)) -> shuf (AND (A, B), C)
+; fold (OR  (shuf (A, C), shuf (B, C)) -> shuf (OR  (A, B), C)
+; fold (XOR (shuf (A, C), shuf (B, C)) -> shuf (XOR (A, B), V_0)
+
+; fold (AND (shuf (C, A), shuf (C, B)) -> shuf (C, AND (A, B))
+; fold (OR  (shuf (C, A), shuf (C, B)) -> shuf (C, OR  (A, B))
+; fold (XOR (shuf (C, A), shuf (C, B)) -> shuf (V_0, XOR (A, B))
+
+
+
+define <4 x i32> @test1(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c) {
+  %shuf1 = shufflevector <4 x i32> %a, <4 x i32> %c, <4 x i32><i32 0, i32 2, i32 1, i32 3>
+  %shuf2 = shufflevector <4 x i32> %b, <4 x i32> %c, <4 x i32><i32 0, i32 2, i32 1, i32 3>
+  %and = and <4 x i32> %shuf1, %shuf2
+  ret <4 x i32> %and
+}
+; CHECK-LABEL: test1
+; CHECK-NOT: pshufd
+; CHECK: pand
+; CHECK-NEXT: pshufd
+; CHECK-NEXT: ret
+
+
+define <4 x i32> @test2(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c) {
+  %shuf1 = shufflevector <4 x i32> %a, <4 x i32> %c, <4 x i32><i32 0, i32 2, i32 1, i32 3>
+  %shuf2 = shufflevector <4 x i32> %b, <4 x i32> %c, <4 x i32><i32 0, i32 2, i32 1, i32 3>
+  %or = or <4 x i32> %shuf1, %shuf2
+  ret <4 x i32> %or
+}
+; CHECK-LABEL: test2
+; CHECK-NOT: pshufd
+; CHECK: por
+; CHECK-NEXT: pshufd
+; CHECK-NEXT: ret
+
+
+define <4 x i32> @test3(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c) {
+  %shuf1 = shufflevector <4 x i32> %a, <4 x i32> %c, <4 x i32><i32 0, i32 2, i32 1, i32 3>
+  %shuf2 = shufflevector <4 x i32> %b, <4 x i32> %c, <4 x i32><i32 0, i32 2, i32 1, i32 3>
+  %xor = xor <4 x i32> %shuf1, %shuf2
+  ret <4 x i32> %xor
+}
+; CHECK-LABEL: test3
+; CHECK-NOT: pshufd
+; CHECK: pxor
+; CHECK-NEXT: pshufd
+; CHECK-NEXT: ret
+
+
+define <4 x i32> @test4(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c) {
+  %shuf1 = shufflevector <4 x i32> %c, <4 x i32> %a, <4 x i32><i32 4, i32 6, i32 5, i32 7>
+  %shuf2 = shufflevector <4 x i32> %c, <4 x i32> %b, <4 x i32><i32 4, i32 6, i32 5, i32 7>
+  %and = and <4 x i32> %shuf1, %shuf2
+  ret <4 x i32> %and
+}
+; CHECK-LABEL: test4
+; CHECK-NOT: pshufd
+; CHECK: pand
+; CHECK-NEXT: pshufd
+; CHECK-NEXT: ret
+
+
+define <4 x i32> @test5(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c) {
+  %shuf1 = shufflevector <4 x i32> %c, <4 x i32> %a, <4 x i32><i32 4, i32 6, i32 5, i32 7>
+  %shuf2 = shufflevector <4 x i32> %c, <4 x i32> %b, <4 x i32><i32 4, i32 6, i32 5, i32 7>
+  %or = or <4 x i32> %shuf1, %shuf2
+  ret <4 x i32> %or
+}
+; CHECK-LABEL: test5
+; CHECK-NOT: pshufd
+; CHECK: por
+; CHECK-NEXT: pshufd
+; CHECK-NEXT: ret
+
+
+define <4 x i32> @test6(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c) {
+  %shuf1 = shufflevector <4 x i32> %c, <4 x i32> %a, <4 x i32><i32 4, i32 6, i32 5, i32 7>
+  %shuf2 = shufflevector <4 x i32> %c, <4 x i32> %b, <4 x i32><i32 4, i32 6, i32 5, i32 7>
+  %xor = xor <4 x i32> %shuf1, %shuf2
+  ret <4 x i32> %xor
+}
+; CHECK-LABEL: test6
+; CHECK-NOT: pshufd
+; CHECK: pxor
+; CHECK-NEXT: pshufd
+; CHECK-NEXT: ret
+
+
+; Verify that DAGCombiner moves the shuffle after the xor/and/or even if shuffles
+; are not performing a swizzle operations.
+
+define <4 x i32> @test1b(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c) {
+  %shuf1 = shufflevector <4 x i32> %a, <4 x i32> %c, <4 x i32><i32 0, i32 5, i32 2, i32 7>
+  %shuf2 = shufflevector <4 x i32> %b, <4 x i32> %c, <4 x i32><i32 0, i32 5, i32 2, i32 7>
+  %and = and <4 x i32> %shuf1, %shuf2
+  ret <4 x i32> %and
+}
+; CHECK-LABEL: test1b
+; CHECK-NOT: blendps
+; CHECK: andps
+; CHECK-NEXT: blendps
+; CHECK-NEXT: ret
+
+
+define <4 x i32> @test2b(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c) {
+  %shuf1 = shufflevector <4 x i32> %a, <4 x i32> %c, <4 x i32><i32 0, i32 5, i32 2, i32 7>
+  %shuf2 = shufflevector <4 x i32> %b, <4 x i32> %c, <4 x i32><i32 0, i32 5, i32 2, i32 7>
+  %or = or <4 x i32> %shuf1, %shuf2
+  ret <4 x i32> %or
+}
+; CHECK-LABEL: test2b
+; CHECK-NOT: blendps
+; CHECK: orps
+; CHECK-NEXT: blendps
+; CHECK-NEXT: ret
+
+
+define <4 x i32> @test3b(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c) {
+  %shuf1 = shufflevector <4 x i32> %a, <4 x i32> %c, <4 x i32><i32 0, i32 5, i32 2, i32 7>
+  %shuf2 = shufflevector <4 x i32> %b, <4 x i32> %c, <4 x i32><i32 0, i32 5, i32 2, i32 7>
+  %xor = xor <4 x i32> %shuf1, %shuf2
+  ret <4 x i32> %xor
+}
+; CHECK-LABEL: test3b
+; CHECK-NOT: blendps
+; CHECK: xorps
+; CHECK-NEXT: xorps
+; CHECK-NEXT: blendps
+; CHECK-NEXT: ret
+
+
+define <4 x i32> @test4b(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c) {
+  %shuf1 = shufflevector <4 x i32> %c, <4 x i32> %a, <4 x i32><i32 0, i32 5, i32 2, i32 7>
+  %shuf2 = shufflevector <4 x i32> %c, <4 x i32> %b, <4 x i32><i32 0, i32 5, i32 2, i32 7>
+  %and = and <4 x i32> %shuf1, %shuf2
+  ret <4 x i32> %and
+}
+; CHECK-LABEL: test4b
+; CHECK-NOT: blendps
+; CHECK: andps
+; CHECK-NEXT: blendps
+; CHECK: ret
+
+
+define <4 x i32> @test5b(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c) {
+  %shuf1 = shufflevector <4 x i32> %c, <4 x i32> %a, <4 x i32><i32 0, i32 5, i32 2, i32 7>
+  %shuf2 = shufflevector <4 x i32> %c, <4 x i32> %b, <4 x i32><i32 0, i32 5, i32 2, i32 7>
+  %or = or <4 x i32> %shuf1, %shuf2
+  ret <4 x i32> %or
+}
+; CHECK-LABEL: test5b
+; CHECK-NOT: blendps
+; CHECK: orps
+; CHECK-NEXT: blendps
+; CHECK: ret
+
+
+define <4 x i32> @test6b(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c) {
+  %shuf1 = shufflevector <4 x i32> %c, <4 x i32> %a, <4 x i32><i32 0, i32 5, i32 2, i32 7>
+  %shuf2 = shufflevector <4 x i32> %c, <4 x i32> %b, <4 x i32><i32 0, i32 5, i32 2, i32 7>
+  %xor = xor <4 x i32> %shuf1, %shuf2
+  ret <4 x i32> %xor
+}
+; CHECK-LABEL: test6b
+; CHECK-NOT: blendps
+; CHECK: xorps
+; CHECK-NEXT: xorps
+; CHECK-NEXT: blendps
+; CHECK: ret
+
+define <4 x i32> @test1c(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c) {
+  %shuf1 = shufflevector <4 x i32> %a, <4 x i32> %c, <4 x i32><i32 0, i32 2, i32 5, i32 7>
+  %shuf2 = shufflevector <4 x i32> %b, <4 x i32> %c, <4 x i32><i32 0, i32 2, i32 5, i32 7>
+  %and = and <4 x i32> %shuf1, %shuf2
+  ret <4 x i32> %and
+}
+; CHECK-LABEL: test1c
+; CHECK-NOT: shufps
+; CHECK: andps
+; CHECK-NEXT: shufps
+; CHECK-NEXT: ret
+
+
+define <4 x i32> @test2c(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c) {
+  %shuf1 = shufflevector <4 x i32> %a, <4 x i32> %c, <4 x i32><i32 0, i32 2, i32 5, i32 7>
+  %shuf2 = shufflevector <4 x i32> %b, <4 x i32> %c, <4 x i32><i32 0, i32 2, i32 5, i32 7>
+  %or = or <4 x i32> %shuf1, %shuf2
+  ret <4 x i32> %or
+}
+; CHECK-LABEL: test2c
+; CHECK-NOT: shufps
+; CHECK: orps
+; CHECK-NEXT: shufps
+; CHECK-NEXT: ret
+
+
+define <4 x i32> @test3c(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c) {
+  %shuf1 = shufflevector <4 x i32> %a, <4 x i32> %c, <4 x i32><i32 0, i32 2, i32 5, i32 7>
+  %shuf2 = shufflevector <4 x i32> %b, <4 x i32> %c, <4 x i32><i32 0, i32 2, i32 5, i32 7>
+  %xor = xor <4 x i32> %shuf1, %shuf2
+  ret <4 x i32> %xor
+}
+; CHECK-LABEL: test3c
+; CHECK-NOT: shufps
+; CHECK: xorps
+; CHECK-NEXT: xorps
+; CHECK-NEXT: shufps
+; CHECK-NEXT: ret
+
+
+define <4 x i32> @test4c(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c) {
+  %shuf1 = shufflevector <4 x i32> %c, <4 x i32> %a, <4 x i32><i32 0, i32 2, i32 5, i32 7>
+  %shuf2 = shufflevector <4 x i32> %c, <4 x i32> %b, <4 x i32><i32 0, i32 2, i32 5, i32 7>
+  %and = and <4 x i32> %shuf1, %shuf2
+  ret <4 x i32> %and
+}
+; CHECK-LABEL: test4c
+; CHECK-NOT: shufps
+; CHECK: andps
+; CHECK-NEXT: shufps
+; CHECK: ret
+
+
+define <4 x i32> @test5c(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c) {
+  %shuf1 = shufflevector <4 x i32> %c, <4 x i32> %a, <4 x i32><i32 0, i32 2, i32 5, i32 7>
+  %shuf2 = shufflevector <4 x i32> %c, <4 x i32> %b, <4 x i32><i32 0, i32 2, i32 5, i32 7>
+  %or = or <4 x i32> %shuf1, %shuf2
+  ret <4 x i32> %or
+}
+; CHECK-LABEL: test5c
+; CHECK-NOT: shufps
+; CHECK: orps
+; CHECK-NEXT: shufps
+; CHECK: ret
+
+
+define <4 x i32> @test6c(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c) {
+  %shuf1 = shufflevector <4 x i32> %c, <4 x i32> %a, <4 x i32><i32 0, i32 2, i32 5, i32 7>
+  %shuf2 = shufflevector <4 x i32> %c, <4 x i32> %b, <4 x i32><i32 0, i32 2, i32 5, i32 7>
+  %xor = xor <4 x i32> %shuf1, %shuf2
+  ret <4 x i32> %xor
+}
+; CHECK-LABEL: test6c
+; CHECK-NOT: shufps
+; CHECK: xorps
+; CHECK-NEXT: xorps
+; CHECK-NEXT: shufps
+; CHECK: ret
+