From 2ee746b87d9471d2dc024827cacdc46114ed3708 Mon Sep 17 00:00:00 2001 From: Nadav Rotem Date: Sun, 12 Feb 2012 15:05:31 +0000 Subject: [PATCH] This patch addresses the problem of poor code generation for the zext v8i8 -> v8i32 on AVX machines. The codegen often scalarizes ANY_EXTEND nodes. The DAGCombiner has two optimizations that can mitigate the problem. First, if all of the operands of a BUILD_VECTOR node are extracted from an ZEXT/ANYEXT nodes, then it is possible to create a new simplified BUILD_VECTOR which uses UNDEFS/ZERO values to eliminate the scalar ZEXT/ANYEXT nodes. Second, another dag combine optimization lowers BUILD_VECTOR into a shuffle vector instruction. In the case of zext v8i8->v8i32 on AVX, a value in an XMM register is to be shuffled into a wide YMM register. This patch modifes the second optimization and allows the creation of shuffle vectors even when the newly generated vector and the original vector from which we extract the values are of different types. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150340 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 43 ++++++++++++++++-------- test/CodeGen/CellSPU/rotate_ops.ll | 2 +- test/CodeGen/X86/avx-zext.ll | 13 +++++++ 3 files changed, 43 insertions(+), 15 deletions(-) diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index d029906fc31..9fa5572e815 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -7253,7 +7253,7 @@ SDValue DAGCombiner::visitBUILD_VECTOR(SDNode *N) { // same source type and all of the inputs must be any or zero extend. // Scalar sizes must be a power of two. EVT OutScalarTy = N->getValueType(0).getScalarType(); - bool validTypes = SourceType != MVT::Other && + bool ValidTypes = SourceType != MVT::Other && isPowerOf2_32(OutScalarTy.getSizeInBits()) && isPowerOf2_32(SourceType.getSizeInBits()); @@ -7263,7 +7263,8 @@ SDValue DAGCombiner::visitBUILD_VECTOR(SDNode *N) { // will be type-legalized to complex code sequences. // We perform this optimization only before the operation legalizer because we // may introduce illegal operations. - if (LegalTypes && !LegalOperations && validTypes) { + if ((Level == AfterLegalizeVectorOps || Level == AfterLegalizeTypes) && + ValidTypes) { bool isLE = TLI.isLittleEndian(); unsigned ElemRatio = OutScalarTy.getSizeInBits()/SourceType.getSizeInBits(); assert(ElemRatio > 1 && "Invalid element size ratio"); @@ -7322,15 +7323,8 @@ SDValue DAGCombiner::visitBUILD_VECTOR(SDNode *N) { break; } - // If the input vector type disagrees with the result of the build_vector, - // we can't make a shuffle. + // We allow up to two distinct input vectors. SDValue ExtractedFromVec = N->getOperand(i).getOperand(0); - if (ExtractedFromVec.getValueType() != VT) { - VecIn1 = VecIn2 = SDValue(0, 0); - break; - } - - // Otherwise, remember this. We allow up to two distinct input vectors. if (ExtractedFromVec == VecIn1 || ExtractedFromVec == VecIn2) continue; @@ -7345,7 +7339,7 @@ SDValue DAGCombiner::visitBUILD_VECTOR(SDNode *N) { } } - // If everything is good, we can make a shuffle operation. + // If everything is good, we can make a shuffle operation. if (VecIn1.getNode()) { SmallVector Mask; for (unsigned i = 0; i != NumInScalars; ++i) { @@ -7371,14 +7365,35 @@ SDValue DAGCombiner::visitBUILD_VECTOR(SDNode *N) { Mask.push_back(Idx+NumInScalars); } - // Add count and size info. - if (!isTypeLegal(VT)) + // We can't generate a shuffle node with mismatched input and output types. + // Attempt to transform a single input vector to the correct type. + if ((VT != VecIn1.getValueType())) { + // We don't support shuffeling between TWO values of different types. + if (VecIn2.getNode() != 0) + return SDValue(); + + // We only support widening of vectors which are half the size of the + // output registers. For example XMM->YMM widening on X86 with AVX. + if (VecIn1.getValueType().getSizeInBits()*2 != VT.getSizeInBits()) + return SDValue(); + + // Widen the input vector by adding undef values. + VecIn1 = DAG.getNode(ISD::CONCAT_VECTORS, N->getDebugLoc(), VT, + VecIn1, DAG.getUNDEF(VecIn1.getValueType())); + } + + // If VecIn2 is unused then change it to undef. + VecIn2 = VecIn2.getNode() ? VecIn2 : DAG.getUNDEF(VT); + + // Only type-legal BUILD_VECTOR nodes are converted to shuffle nodes. + if (!isTypeLegal(VT) || !isTypeLegal(VecIn1.getValueType()) || + !isTypeLegal(VecIn2.getValueType())) return SDValue(); // Return the new VECTOR_SHUFFLE node. SDValue Ops[2]; Ops[0] = VecIn1; - Ops[1] = VecIn2.getNode() ? VecIn2 : DAG.getUNDEF(VT); + Ops[1] = VecIn2; return DAG.getVectorShuffle(VT, N->getDebugLoc(), Ops[0], Ops[1], &Mask[0]); } diff --git a/test/CodeGen/CellSPU/rotate_ops.ll b/test/CodeGen/CellSPU/rotate_ops.ll index 8b7af20b4a9..97709352760 100644 --- a/test/CodeGen/CellSPU/rotate_ops.ll +++ b/test/CodeGen/CellSPU/rotate_ops.ll @@ -1,5 +1,5 @@ ; RUN: llc < %s -march=cellspu -o %t1.s -; RUN: grep rot %t1.s | count 85 +; RUN: grep rot %t1.s | count 86 ; RUN: grep roth %t1.s | count 8 ; RUN: grep roti.*5 %t1.s | count 1 ; RUN: grep roti.*27 %t1.s | count 1 diff --git a/test/CodeGen/X86/avx-zext.ll b/test/CodeGen/X86/avx-zext.ll index 795a7b3dd45..b630e9d1461 100755 --- a/test/CodeGen/X86/avx-zext.ll +++ b/test/CodeGen/X86/avx-zext.ll @@ -3,6 +3,7 @@ define <8 x i32> @zext_8i16_to_8i32(<8 x i16> %A) nounwind uwtable readnone ssp { ;CHECK: zext_8i16_to_8i32 ;CHECK: vpunpckhwd +;CHECK: ret %B = zext <8 x i16> %A to <8 x i32> ret <8 x i32>%B @@ -11,7 +12,19 @@ define <8 x i32> @zext_8i16_to_8i32(<8 x i16> %A) nounwind uwtable readnone ssp define <4 x i64> @zext_4i32_to_4i64(<4 x i32> %A) nounwind uwtable readnone ssp { ;CHECK: zext_4i32_to_4i64 ;CHECK: vpunpckhdq +;CHECK: ret %B = zext <4 x i32> %A to <4 x i64> ret <4 x i64>%B } + + +define <8 x i32> @zext_8i8_to_8i32(<8 x i8> %z) { +;CHECK: zext_8i8_to_8i32 +;CHECK: vpunpckhwd +;CHECK: vpunpcklwd +;CHECK: vinsertf128 +;CHECK: ret + %t = zext <8 x i8> %z to <8 x i32> + ret <8 x i32> %t +}