From 047542669a20505fc7c5f2d93caa5610aa3db2c5 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Tue, 20 Apr 2010 05:32:14 +0000 Subject: [PATCH] move some select simplifications out out instcombine into inst simplify. No functionality change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101873 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/Analysis/InstructionSimplify.h | 4 ++ lib/Analysis/InstructionSimplify.cpp | 32 ++++++++++++++ .../InstCombine/InstCombineSelect.cpp | 44 ++++++------------- 3 files changed, 49 insertions(+), 31 deletions(-) diff --git a/include/llvm/Analysis/InstructionSimplify.h b/include/llvm/Analysis/InstructionSimplify.h index 13314e6ea0e..f47e740a741 100644 --- a/include/llvm/Analysis/InstructionSimplify.h +++ b/include/llvm/Analysis/InstructionSimplify.h @@ -46,6 +46,10 @@ namespace llvm { Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS, const TargetData *TD = 0); + /// SimplifySelectInst - Given operands for a SelectInst, see if we can fold + /// the result. If not, this returns null. + Value *SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal, + const TargetData *TD = 0); /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can /// fold the result. If not, this returns null. diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp index 8288e96eb77..dbefc2dedb2 100644 --- a/lib/Analysis/InstructionSimplify.cpp +++ b/lib/Analysis/InstructionSimplify.cpp @@ -314,6 +314,35 @@ Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS, return 0; } +/// SimplifySelectInst - Given operands for a SelectInst, see if we can fold +/// the result. If not, this returns null. +Value *llvm::SimplifySelectInst(Value *CondVal, Value *TrueVal, Value *FalseVal, + const TargetData *TD) { + // select true, X, Y -> X + // select false, X, Y -> Y + if (ConstantInt *CB = dyn_cast(CondVal)) + return CB->getZExtValue() ? TrueVal : FalseVal; + + // select C, X, X -> X + if (TrueVal == FalseVal) + return TrueVal; + + if (isa(TrueVal)) // select C, undef, X -> X + return FalseVal; + if (isa(FalseVal)) // select C, X, undef -> X + return TrueVal; + if (isa(CondVal)) { // select undef, X, Y -> X or Y + if (isa(TrueVal)) + return TrueVal; + return FalseVal; + } + + + + return 0; +} + + /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can /// fold the result. If not, this returns null. Value *llvm::SimplifyGEPInst(Value *const *Ops, unsigned NumOps, @@ -391,6 +420,9 @@ Value *llvm::SimplifyInstruction(Instruction *I, const TargetData *TD) { case Instruction::FCmp: return SimplifyFCmpInst(cast(I)->getPredicate(), I->getOperand(0), I->getOperand(1), TD); + case Instruction::Select: + return SimplifySelectInst(I->getOperand(0), I->getOperand(1), + I->getOperand(2), TD); case Instruction::GetElementPtr: { SmallVector Ops(I->op_begin(), I->op_end()); return SimplifyGEPInst(&Ops[0], Ops.size(), TD); diff --git a/lib/Transforms/InstCombine/InstCombineSelect.cpp b/lib/Transforms/InstCombine/InstCombineSelect.cpp index 2fc932594f7..c958cde0917 100644 --- a/lib/Transforms/InstCombine/InstCombineSelect.cpp +++ b/lib/Transforms/InstCombine/InstCombineSelect.cpp @@ -13,6 +13,7 @@ #include "InstCombine.h" #include "llvm/Support/PatternMatch.h" +#include "llvm/Analysis/InstructionSimplify.h" using namespace llvm; using namespace PatternMatch; @@ -421,49 +422,30 @@ Instruction *InstCombiner::visitSelectInst(SelectInst &SI) { Value *TrueVal = SI.getTrueValue(); Value *FalseVal = SI.getFalseValue(); - // select true, X, Y -> X - // select false, X, Y -> Y - if (ConstantInt *C = dyn_cast(CondVal)) - return ReplaceInstUsesWith(SI, C->getZExtValue() ? TrueVal : FalseVal); - - // select C, X, X -> X - if (TrueVal == FalseVal) - return ReplaceInstUsesWith(SI, TrueVal); - - if (isa(TrueVal)) // select C, undef, X -> X - return ReplaceInstUsesWith(SI, FalseVal); - if (isa(FalseVal)) // select C, X, undef -> X - return ReplaceInstUsesWith(SI, TrueVal); - if (isa(CondVal)) { // select undef, X, Y -> X or Y - if (isa(TrueVal)) - return ReplaceInstUsesWith(SI, TrueVal); - else - return ReplaceInstUsesWith(SI, FalseVal); - } + if (Value *V = SimplifySelectInst(CondVal, TrueVal, FalseVal, TD)) + return ReplaceInstUsesWith(SI, V); if (SI.getType()->isIntegerTy(1)) { if (ConstantInt *C = dyn_cast(TrueVal)) { if (C->getZExtValue()) { // Change: A = select B, true, C --> A = or B, C return BinaryOperator::CreateOr(CondVal, FalseVal); - } else { - // Change: A = select B, false, C --> A = and !B, C - Value *NotCond = - InsertNewInstBefore(BinaryOperator::CreateNot(CondVal, - "not."+CondVal->getName()), SI); - return BinaryOperator::CreateAnd(NotCond, FalseVal); } + // Change: A = select B, false, C --> A = and !B, C + Value *NotCond = + InsertNewInstBefore(BinaryOperator::CreateNot(CondVal, + "not."+CondVal->getName()), SI); + return BinaryOperator::CreateAnd(NotCond, FalseVal); } else if (ConstantInt *C = dyn_cast(FalseVal)) { if (C->getZExtValue() == false) { // Change: A = select B, C, false --> A = and B, C return BinaryOperator::CreateAnd(CondVal, TrueVal); - } else { - // Change: A = select B, C, true --> A = or !B, C - Value *NotCond = - InsertNewInstBefore(BinaryOperator::CreateNot(CondVal, - "not."+CondVal->getName()), SI); - return BinaryOperator::CreateOr(NotCond, TrueVal); } + // Change: A = select B, C, true --> A = or !B, C + Value *NotCond = + InsertNewInstBefore(BinaryOperator::CreateNot(CondVal, + "not."+CondVal->getName()), SI); + return BinaryOperator::CreateOr(NotCond, TrueVal); } // select a, b, a -> a&b