From e58a780166eb684164a0a95b999f29328d4e9b2b Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sun, 2 Apr 2006 03:41:14 +0000 Subject: [PATCH] Intrinsics that just load from memory can be treated like loads: they don't have to serialize against each other. This allows us to schedule lvx's across each other, for example. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27346 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp | 29 ++++++++++++++++--- 1 file changed, 25 insertions(+), 4 deletions(-) diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp index 5a95ff0bc53..2f79fe56806 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp @@ -1236,16 +1236,32 @@ static bool IntrinsicCannotAccessMemory(unsigned IntrinsicID) { return false; } +// IntrinsicOnlyReadsMemory - Return true if the specified intrinsic doesn't +// have any side-effects or if it only reads memory. +static bool IntrinsicOnlyReadsMemory(unsigned IntrinsicID) { +#define GET_SIDE_EFFECT_INFO +#include "llvm/Intrinsics.gen" +#undef GET_SIDE_EFFECT_INFO + return false; +} + /// visitTargetIntrinsic - Lower a call of a target intrinsic to an INTRINSIC /// node. void SelectionDAGLowering::visitTargetIntrinsic(CallInst &I, unsigned Intrinsic) { bool HasChain = !IntrinsicCannotAccessMemory(Intrinsic); + bool OnlyLoad = HasChain && IntrinsicOnlyReadsMemory(Intrinsic); // Build the operand list. std::vector Ops; - if (HasChain) // If this intrinsic has side-effects, chainify it. - Ops.push_back(getRoot()); + if (HasChain) { // If this intrinsic has side-effects, chainify it. + if (OnlyLoad) { + // We don't need to serialize loads against other loads. + Ops.push_back(DAG.getRoot()); + } else { + Ops.push_back(getRoot()); + } + } // Add the intrinsic ID as an integer operand. Ops.push_back(DAG.getConstant(Intrinsic, TLI.getPointerTy())); @@ -1295,8 +1311,13 @@ void SelectionDAGLowering::visitTargetIntrinsic(CallInst &I, else Result = DAG.getNode(ISD::INTRINSIC_VOID, VTs, Ops); - if (HasChain) - DAG.setRoot(Result.getValue(Result.Val->getNumValues()-1)); + if (HasChain) { + SDOperand Chain = Result.getValue(Result.Val->getNumValues()-1); + if (OnlyLoad) + PendingLoads.push_back(Chain); + else + DAG.setRoot(Chain); + } if (I.getType() != Type::VoidTy) { if (const PackedType *PTy = dyn_cast(I.getType())) { MVT::ValueType EVT = TLI.getValueType(PTy->getElementType()); -- 2.34.1