[llvm] r211771 - [X86] Improve the selection of SSE3/AVX addsub instructions.
Andrea Di Biagio
Andrea_DiBiagio at sn.scee.net
Thu Jun 26 03:45:22 PDT 2014
Author: adibiagio
Date: Thu Jun 26 05:45:21 2014
New Revision: 211771
URL: http://llvm.org/viewvc/llvm-project?rev=211771&view=rev
Log:
[X86] Improve the selection of SSE3/AVX addsub instructions.
This patch teaches the backend how to canonicalize a shuffle 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.
In general, ISel only knows how to pattern-match a canonical
'fadd + fsub + blendi' dag node sequence into an ADDSUB instruction.
This new rule allows to convert a non-canonical dag sequence into a
canonical one that will be matched by a single ADDSUB at ISel stage.
The idea of converting a non-canonical ADDSUB into a canonical one by
swapping the first two operands of the shuffle, and then negating the
second operand of the FADD and FSUB, was originally proposed by Hal Finkel.
Modified:
llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
llvm/trunk/test/CodeGen/X86/sse3-avx-addsub.ll
Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=211771&r1=211770&r2=211771&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Thu Jun 26 05:45:21 2014
@@ -18014,6 +18014,49 @@ static SDValue PerformShuffleCombine(SDN
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] == (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()))
Modified: llvm/trunk/test/CodeGen/X86/sse3-avx-addsub.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/sse3-avx-addsub.ll?rev=211771&r1=211770&r2=211771&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/sse3-avx-addsub.ll (original)
+++ llvm/trunk/test/CodeGen/X86/sse3-avx-addsub.ll Thu Jun 26 05:45:21 2014
@@ -3,7 +3,7 @@
; Test ADDSUB ISel patterns.
-; All the functions below are obtained from the following source:
+; Functions below are obtained from the following source:
;
; typedef double double2 __attribute__((ext_vector_type(2)));
; typedef double double4 __attribute__((ext_vector_type(4)));
@@ -19,7 +19,7 @@
; 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], [7]};
+; return (float8){X[0], Y[1], X[2], Y[3], X[4], Y[5], X[6], Y[7]};
; }
;
; double4 test3(double4 A, double4 B) {
@@ -141,3 +141,156 @@ define <2 x double> @test4b(<2 x double>
; 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
+
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