Revert r211771. It was: "[X86] Improve the selection of SSE3/AVX addsub instructions".

This chang fully reverts r211771.
That revision added a canonicalization rule which has the potential to causes a
combine-cycle in the target-independent canonicalizing DAG combine.

The plan is to move the logic that forms target specific addsub nodes as part of
the lowering of shuffles.

llvm-svn: 213736

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 9e13fd3..e9f48a5 100644 (file)
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -18783,49 +18783,6 @@ static SDValue PerformShuffleCombine(SDNode *N, SelectionDAG &DAG,
   SDValue N1 = N->getOperand(1);
   EVT VT = N->getValueType(0);
 
-  // Canonicalize shuffles that perform 'addsub' on packed float vectors
-  // according to the rule:
-  //  (shuffle (FADD A, B), (FSUB A, B), Mask) ->
-  //  (shuffle (FSUB A, -B), (FADD A, -B), Mask)
-  //
-  // Where 'Mask' is:
-  //  <0,5,2,7>             -- for v4f32 and v4f64 shuffles;
-  //  <0,3>                 -- for v2f64 shuffles;
-  //  <0,9,2,11,4,13,6,15>  -- for v8f32 shuffles.
-  //
-  // This helps pattern-matching more SSE3/AVX ADDSUB instructions
-  // during ISel stage.
-  if (N->getOpcode() == ISD::VECTOR_SHUFFLE &&
-      ((Subtarget->hasSSE3() && (VT == MVT::v4f32 || VT == MVT::v2f64)) ||
-       (Subtarget->hasAVX() && (VT == MVT::v8f32 || VT == MVT::v4f64))) &&
-      N0->getOpcode() == ISD::FADD && N1->getOpcode() == ISD::FSUB &&
-      // Operands to the FADD and FSUB must be the same.
-      ((N0->getOperand(0) == N1->getOperand(0) &&
-        N0->getOperand(1) == N1->getOperand(1)) ||
-       // FADD is commutable. See if by commuting the operands of the FADD
-       // we would still be able to match the operands of the FSUB dag node.
-       (N0->getOperand(1) == N1->getOperand(0) &&
-        N0->getOperand(0) == N1->getOperand(1))) &&
-      N0->getOperand(0)->getOpcode() != ISD::UNDEF &&
-      N0->getOperand(1)->getOpcode() != ISD::UNDEF) {
-    
-    ShuffleVectorSDNode *SV = cast<ShuffleVectorSDNode>(N);
-    unsigned NumElts = VT.getVectorNumElements();
-    ArrayRef<int> Mask = SV->getMask();
-    bool CanFold = true;
-
-    for (unsigned i = 0, e = NumElts; i != e && CanFold; ++i)
-      CanFold = Mask[i] == (int)((i & 1) ? i + NumElts : i);
-
-    if (CanFold) {
-      SDValue Op0 = N1->getOperand(0);
-      SDValue Op1 = DAG.getNode(ISD::FNEG, dl, VT, N1->getOperand(1));
-      SDValue Sub = DAG.getNode(ISD::FSUB, dl, VT, Op0, Op1);
-      SDValue Add = DAG.getNode(ISD::FADD, dl, VT, Op0, Op1);
-      return DAG.getVectorShuffle(VT, dl, Sub, Add, Mask);
-    }
-  }
-
   // Don't create instructions with illegal types after legalize types has run.
   const TargetLowering &TLI = DAG.getTargetLoweringInfo();
   if (!DCI.isBeforeLegalize() && !TLI.isTypeLegal(VT.getVectorElementType()))

diff --git a/llvm/test/CodeGen/X86/sse3-avx-addsub.ll b/llvm/test/CodeGen/X86/sse3-avx-addsub.ll
index 8b66743..4852491 100644 (file)
--- a/llvm/test/CodeGen/X86/sse3-avx-addsub.ll
+++ b/llvm/test/CodeGen/X86/sse3-avx-addsub.ll
@@ -141,156 +141,3 @@ define <2 x double> @test4b(<2 x double> %A, <2 x double>* %B) {
 ; AVX: vaddsubpd
 ; CHECK-NEXT: ret
 
-; Functions below are obtained from the following source:
-;
-; float4 test1(float4 A, float4 B) {
-;   float4 X = A + B;
-;   float4 Y = A - B;
-;   return (float4){X[0], Y[1], X[2], Y[3]};
-; }
-;
-; float8 test2(float8 A, float8 B) {
-;   float8 X = A + B;
-;   float8 Y = A - B;
-;   return (float8){X[0], Y[1], X[2], Y[3], X[4], Y[5], X[6], Y[7]};
-; }
-;
-; double4 test3(double4 A, double4 B) {
-;   double4 X = A + B;
-;   double4 Y = A - B;
-;   return (double4){X[0], Y[1], X[2], Y[3]};
-; }
-;
-; double2 test4(double2 A, double2 B) {
-;   double2 X = A + B;
-;   double2 Y = A - B;
-;   return (double2){X[0], Y[1]};
-; }
-
-define <4 x float> @test5(<4 x float> %A, <4 x float> %B) {
-  %sub = fsub <4 x float> %A, %B
-  %add = fadd <4 x float> %A, %B
-  %vecinit6 = shufflevector <4 x float> %add, <4 x float> %sub, <4 x i32> <i32 0, i32 5, i32 2, i32 7>
-  ret <4 x float> %vecinit6
-}
-; CHECK-LABEL: test5
-; SSE: xorps
-; SSE-NEXT: addsubps
-; AVX: vxorps
-; AVX-NEXT: vaddsubps
-; CHECK: ret
-
-
-define <8 x float> @test6(<8 x float> %A, <8 x float> %B) {
-  %sub = fsub <8 x float> %A, %B
-  %add = fadd <8 x float> %A, %B
-  %vecinit14 = shufflevector <8 x float> %add, <8 x float> %sub, <8 x i32> <i32 0, i32 9, i32 2, i32 11, i32 4, i32 13, i32 6, i32 15>
-  ret <8 x float> %vecinit14
-}
-; CHECK-LABEL: test6
-; SSE: xorps
-; SSE-NEXT: addsubps
-; SSE: xorps
-; SSE-NEXT: addsubps
-; AVX: vxorps
-; AVX-NEXT: vaddsubps
-; AVX-NOT: vxorps
-; AVX-NOT: vaddsubps
-; CHECK: ret
-
-
-define <4 x double> @test7(<4 x double> %A, <4 x double> %B) {
-  %sub = fsub <4 x double> %A, %B
-  %add = fadd <4 x double> %A, %B
-  %vecinit6 = shufflevector <4 x double> %add, <4 x double> %sub, <4 x i32> <i32 0, i32 5, i32 2, i32 7>
-  ret <4 x double> %vecinit6
-}
-; CHECK-LABEL: test7
-; SSE: xorpd
-; SSE-NEXT: addsubpd
-; SSE: xorpd
-; SSE-NEXT: addsubpd
-; AVX: vxorpd
-; AVX-NEXT: vaddsubpd
-; AVX-NOT: vxorpd
-; AVX-NOT: vaddsubpd
-; CHECK: ret
-
-
-define <2 x double> @test8(<2 x double> %A, <2 x double> %B) #0 {
-  %add = fadd <2 x double> %A, %B
-  %sub = fsub <2 x double> %A, %B
-  %vecinit2 = shufflevector <2 x double> %add, <2 x double> %sub, <2 x i32> <i32 0, i32 3>
-  ret <2 x double> %vecinit2
-}
-; CHECK-LABEL: test8
-; SSE: xorpd
-; SSE-NEXT: addsubpd
-; AVX: vxorpd
-; AVX-NEXT: vaddsubpd
-; CHECK: ret
-
-
-define <4 x float> @test5b(<4 x float> %A, <4 x float> %B) {
-  %sub = fsub <4 x float> %A, %B
-  %add = fadd <4 x float> %B, %A
-  %vecinit6 = shufflevector <4 x float> %add, <4 x float> %sub, <4 x i32> <i32 0, i32 5, i32 2, i32 7>
-  ret <4 x float> %vecinit6
-}
-; CHECK-LABEL: test5
-; SSE: xorps
-; SSE-NEXT: addsubps
-; AVX: vxorps
-; AVX-NEXT: vaddsubps
-; CHECK: ret
-
-
-define <8 x float> @test6b(<8 x float> %A, <8 x float> %B) {
-  %sub = fsub <8 x float> %A, %B
-  %add = fadd <8 x float> %B, %A
-  %vecinit14 = shufflevector <8 x float> %add, <8 x float> %sub, <8 x i32> <i32 0, i32 9, i32 2, i32 11, i32 4, i32 13, i32 6, i32 15>
-  ret <8 x float> %vecinit14
-}
-; CHECK-LABEL: test6
-; SSE: xorps
-; SSE-NEXT: addsubps
-; SSE: xorps
-; SSE-NEXT: addsubps
-; AVX: vxorps
-; AVX-NEXT: vaddsubps
-; AVX-NOT: vxorps
-; AVX-NOT: vaddsubps
-; CHECK: ret
-
-
-define <4 x double> @test7b(<4 x double> %A, <4 x double> %B) {
-  %sub = fsub <4 x double> %A, %B
-  %add = fadd <4 x double> %B, %A
-  %vecinit6 = shufflevector <4 x double> %add, <4 x double> %sub, <4 x i32> <i32 0, i32 5, i32 2, i32 7>
-  ret <4 x double> %vecinit6
-}
-; CHECK-LABEL: test7
-; SSE: xorpd
-; SSE-NEXT: addsubpd
-; SSE: xorpd
-; SSE-NEXT: addsubpd
-; AVX: vxorpd
-; AVX-NEXT: vaddsubpd
-; AVX-NOT: vxorpd
-; AVX-NOT: vaddsubpd
-; CHECK: ret
-
-
-define <2 x double> @test8b(<2 x double> %A, <2 x double> %B) #0 {
-  %add = fadd <2 x double> %B, %A
-  %sub = fsub <2 x double> %A, %B
-  %vecinit2 = shufflevector <2 x double> %add, <2 x double> %sub, <2 x i32> <i32 0, i32 3>
-  ret <2 x double> %vecinit2
-}
-; CHECK-LABEL: test8
-; SSE: xorpd
-; SSE-NEXT: addsubpd
-; AVX: vxorpd
-; AVX-NEXT: vaddsubpd
-; CHECK: ret
-