[llvm] r246622 - Optimization for Gather/Scatter with uniform base
Elena Demikhovsky via llvm-commits
llvm-commits at lists.llvm.org
Wed Sep 2 01:39:13 PDT 2015
Author: delena
Date: Wed Sep 2 03:39:13 2015
New Revision: 246622
URL: http://llvm.org/viewvc/llvm-project?rev=246622&view=rev
Log:
Optimization for Gather/Scatter with uniform base
Vector 'getelementptr' with scalar base is an opportunity for gather/scatter intrinsic to generate a better sequence.
While looking for uniform base, we want to use the scalar base pointer of GEP, if exists.
Differential Revision: http://reviews.llvm.org/D11121
Modified:
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
llvm/trunk/test/CodeGen/X86/masked_gather_scatter.ll
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp?rev=246622&r1=246621&r2=246622&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp Wed Sep 2 03:39:13 2015
@@ -3142,51 +3142,63 @@ void SelectionDAGBuilder::visitMaskedSto
setValue(&I, StoreNode);
}
-// Gather/scatter receive a vector of pointers.
-// This vector of pointers may be represented as a base pointer + vector of
-// indices, it depends on GEP and instruction preceding GEP
-// that calculates indices
+// Get a uniform base for the Gather/Scatter intrinsic.
+// The first argument of the Gather/Scatter intrinsic is a vector of pointers.
+// We try to represent it as a base pointer + vector of indices.
+// Usually, the vector of pointers comes from a 'getelementptr' instruction.
+// The first operand of the GEP may be a single pointer or a vector of pointers
+// Example:
+// %gep.ptr = getelementptr i32, <8 x i32*> %vptr, <8 x i32> %ind
+// or
+// %gep.ptr = getelementptr i32, i32* %ptr, <8 x i32> %ind
+// %res = call <8 x i32> @llvm.masked.gather.v8i32(<8 x i32*> %gep.ptr, ..
+//
+// When the first GEP operand is a single pointer - it is the uniform base we
+// are looking for. If first operand of the GEP is a splat vector - we
+// extract the spalt value and use it as a uniform base.
+// In all other cases the function returns 'false'.
+//
static bool getUniformBase(Value *& Ptr, SDValue& Base, SDValue& Index,
SelectionDAGBuilder* SDB) {
- assert(Ptr->getType()->isVectorTy() && "Unexpected pointer type");
+ SelectionDAG& DAG = SDB->DAG;
+ LLVMContext &Context = *DAG.getContext();
+
+ assert(Ptr->getType()->isVectorTy() && "Uexpected pointer type");
GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Ptr);
if (!GEP || GEP->getNumOperands() > 2)
return false;
- Value *GEPPtrs = GEP->getPointerOperand();
- if (!(Ptr = getSplatValue(GEPPtrs)))
- return false;
- SelectionDAG& DAG = SDB->DAG;
- const TargetLowering &TLI = DAG.getTargetLoweringInfo();
- // Check is the Ptr is inside current basic block
- // If not, look for the shuffle instruction
- if (SDB->findValue(Ptr))
- Base = SDB->getValue(Ptr);
- else if (SDB->findValue(GEPPtrs)) {
- SDValue GEPPtrsVal = SDB->getValue(GEPPtrs);
- SDLoc sdl = GEPPtrsVal;
- EVT IdxVT = TLI.getVectorIdxTy(DAG.getDataLayout());
- Base = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, sdl,
- GEPPtrsVal.getValueType().getScalarType(), GEPPtrsVal,
- DAG.getConstant(0, sdl, IdxVT));
- SDB->setValue(Ptr, Base);
- }
- else
+ Value *GEPPtr = GEP->getPointerOperand();
+ if (!GEPPtr->getType()->isVectorTy())
+ Ptr = GEPPtr;
+ else if (!(Ptr = getSplatValue(GEPPtr)))
return false;
Value *IndexVal = GEP->getOperand(1);
- if (SDB->findValue(IndexVal)) {
- Index = SDB->getValue(IndexVal);
- if (SExtInst* Sext = dyn_cast<SExtInst>(IndexVal)) {
+ // The operands of the GEP may be defined in another basic block.
+ // In this case we'll not find nodes for the operands.
+ if (!SDB->findValue(Ptr) || !SDB->findValue(IndexVal))
+ return false;
+
+ Base = SDB->getValue(Ptr);
+ Index = SDB->getValue(IndexVal);
+
+ // Suppress sign extension.
+ if (SExtInst* Sext = dyn_cast<SExtInst>(IndexVal)) {
+ if (SDB->findValue(Sext->getOperand(0))) {
IndexVal = Sext->getOperand(0);
- if (SDB->findValue(IndexVal))
- Index = SDB->getValue(IndexVal);
+ Index = SDB->getValue(IndexVal);
}
- return true;
}
- return false;
+ if (!Index.getValueType().isVector()) {
+ unsigned GEPWidth = GEP->getType()->getVectorNumElements();
+ EVT VT = EVT::getVectorVT(Context, Index.getValueType(), GEPWidth);
+ SmallVector<SDValue, 16> Ops(GEPWidth, Index);
+ Index = DAG.getNode(ISD::BUILD_VECTOR, SDLoc(Index), VT, Ops);
+ }
+ return true;
}
void SelectionDAGBuilder::visitMaskedScatter(const CallInst &I) {
Modified: llvm/trunk/test/CodeGen/X86/masked_gather_scatter.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/masked_gather_scatter.ll?rev=246622&r1=246621&r2=246622&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/masked_gather_scatter.ll (original)
+++ llvm/trunk/test/CodeGen/X86/masked_gather_scatter.ll Wed Sep 2 03:39:13 2015
@@ -140,3 +140,108 @@ define <16 x i32> @test8(<16 x i32*> %pt
%res = add <16 x i32> %gt1, %gt2
ret <16 x i32> %res
}
+
+%struct.RT = type { i8, [10 x [20 x i32]], i8 }
+%struct.ST = type { i32, double, %struct.RT }
+
+; Masked gather for agregate types
+; Test9 and Test10 should give the same result (scalar and vector indices in GEP)
+
+; KNL-LABEL: test9
+; KNL: vpbroadcastq %rdi, %zmm
+; KNL: vpmovsxdq
+; KNL: vpbroadcastq
+; KNL: vpmuludq
+; KNL: vpaddq
+; KNL: vpaddq
+; KNL: vpaddq
+; KNL: vpaddq
+; KNL: vpgatherqd (,%zmm
+
+define <8 x i32> @test9(%struct.ST* %base, <8 x i64> %ind1, <8 x i32>%ind5) {
+entry:
+ %broadcast.splatinsert = insertelement <8 x %struct.ST*> undef, %struct.ST* %base, i32 0
+ %broadcast.splat = shufflevector <8 x %struct.ST*> %broadcast.splatinsert, <8 x %struct.ST*> undef, <8 x i32> zeroinitializer
+
+ %arrayidx = getelementptr %struct.ST, <8 x %struct.ST*> %broadcast.splat, <8 x i64> %ind1, <8 x i32> <i32 2, i32 2, i32 2, i32 2, i32 2, i32 2, i32 2, i32 2>, <8 x i32><i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1>, <8 x i32> %ind5, <8 x i64> <i64 13, i64 13, i64 13, i64 13, i64 13, i64 13, i64 13, i64 13>
+ %res = call <8 x i32 > @llvm.masked.gather.v8i32(<8 x i32*>%arrayidx, i32 4, <8 x i1> <i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true>, <8 x i32> undef)
+ ret <8 x i32> %res
+}
+
+; KNL-LABEL: test10
+; KNL: vpbroadcastq %rdi, %zmm
+; KNL: vpmovsxdq
+; KNL: vpbroadcastq
+; KNL: vpmuludq
+; KNL: vpaddq
+; KNL: vpaddq
+; KNL: vpaddq
+; KNL: vpaddq
+; KNL: vpgatherqd (,%zmm
+define <8 x i32> @test10(%struct.ST* %base, <8 x i64> %i1, <8 x i32>%ind5) {
+entry:
+ %broadcast.splatinsert = insertelement <8 x %struct.ST*> undef, %struct.ST* %base, i32 0
+ %broadcast.splat = shufflevector <8 x %struct.ST*> %broadcast.splatinsert, <8 x %struct.ST*> undef, <8 x i32> zeroinitializer
+
+ %arrayidx = getelementptr %struct.ST, <8 x %struct.ST*> %broadcast.splat, <8 x i64> %i1, i32 2, i32 1, <8 x i32> %ind5, i64 13
+ %res = call <8 x i32 > @llvm.masked.gather.v8i32(<8 x i32*>%arrayidx, i32 4, <8 x i1> <i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true>, <8 x i32> undef)
+ ret <8 x i32> %res
+}
+
+; Splat index in GEP, requires broadcast
+; KNL-LABEL: test11
+; KNL: vpbroadcastd %esi, %zmm
+; KNL: vgatherdps (%rdi,%zmm
+define <16 x float> @test11(float* %base, i32 %ind) {
+
+ %broadcast.splatinsert = insertelement <16 x float*> undef, float* %base, i32 0
+ %broadcast.splat = shufflevector <16 x float*> %broadcast.splatinsert, <16 x float*> undef, <16 x i32> zeroinitializer
+
+ %gep.random = getelementptr float, <16 x float*> %broadcast.splat, i32 %ind
+
+ %res = call <16 x float> @llvm.masked.gather.v16f32(<16 x float*> %gep.random, i32 4, <16 x i1> <i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true>, <16 x float> undef)
+ ret <16 x float>%res
+}
+
+; We are checking the uniform base here. It is taken directly from input to vgatherdps
+; KNL-LABEL: test12
+; KNL: kxnorw %k1, %k1, %k1
+; KNL: vgatherdps (%rdi,%zmm
+define <16 x float> @test12(float* %base, <16 x i32> %ind) {
+
+ %sext_ind = sext <16 x i32> %ind to <16 x i64>
+ %gep.random = getelementptr float, float *%base, <16 x i64> %sext_ind
+
+ %res = call <16 x float> @llvm.masked.gather.v16f32(<16 x float*> %gep.random, i32 4, <16 x i1> <i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true>, <16 x float> undef)
+ ret <16 x float>%res
+}
+
+; The same as the previous, but the mask is undefined
+; KNL-LABEL: test13
+; KNL-NOT: kxnorw
+; KNL: vgatherdps (%rdi,%zmm
+define <16 x float> @test13(float* %base, <16 x i32> %ind) {
+
+ %sext_ind = sext <16 x i32> %ind to <16 x i64>
+ %gep.random = getelementptr float, float *%base, <16 x i64> %sext_ind
+
+ %res = call <16 x float> @llvm.masked.gather.v16f32(<16 x float*> %gep.random, i32 4, <16 x i1> undef, <16 x float> undef)
+ ret <16 x float>%res
+}
+
+; The base pointer is not splat, can't find unform base
+; KNL-LABEL: test14
+; KNL: vgatherqps (,%zmm0)
+; KNL: vgatherqps (,%zmm0)
+define <16 x float> @test14(float* %base, i32 %ind, <16 x float*> %vec) {
+
+ %broadcast.splatinsert = insertelement <16 x float*> %vec, float* %base, i32 1
+ %broadcast.splat = shufflevector <16 x float*> %broadcast.splatinsert, <16 x float*> undef, <16 x i32> zeroinitializer
+
+ %gep.random = getelementptr float, <16 x float*> %broadcast.splat, i32 %ind
+
+ %res = call <16 x float> @llvm.masked.gather.v16f32(<16 x float*> %gep.random, i32 4, <16 x i1> undef, <16 x float> undef)
+ ret <16 x float>%res
+}
+
+
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