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remove a bunch of ad-hoc code to simplify instructions from

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loop unswitch, and use inst simplify instead.  It is more
powerful and less duplication.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101874 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2010-04-20 05:33:18 +00:00
parent 047542669a
commit 4f1f6f6342
1 changed files with 12 additions and 43 deletions
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55
lib/Transforms/Scalar/LoopUnswitch.cpp
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@ -34,6 +34,7 @@
#include "llvm/Instructions.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/InlineCost.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/Dominators.h"
@ -988,47 +989,16 @@ void LoopUnswitch::SimplifyCode(std::vector<Instruction*> &Worklist, Loop *L) {
continue;
}
// FIXME: Change this to use instruction simplify interfaces!
// See if instruction simplification can hack this up. This is common for
// things like "select false, X, Y" after unswitching made the condition be
// 'false'.
if (Value *V = SimplifyInstruction(I)) {
ReplaceUsesOfWith(I, V, Worklist, L, LPM);
continue;
}
// Special case hacks that appear commonly in unswitched code.
switch (I->getOpcode()) {
case Instruction::Select:
if (ConstantInt *CB = dyn_cast<ConstantInt>(I->getOperand(0))) {
ReplaceUsesOfWith(I, I->getOperand(!CB->getZExtValue()+1), Worklist, L,
LPM);
continue;
}
break;
case Instruction::And:
if (isa<ConstantInt>(I->getOperand(0)) &&
// constant -> RHS
I->getOperand(0)->getType()->isIntegerTy(1))
cast<BinaryOperator>(I)->swapOperands();
if (ConstantInt *CB = dyn_cast<ConstantInt>(I->getOperand(1)))
if (CB->getType()->isIntegerTy(1)) {
if (CB->isOne()) // X & 1 -> X
ReplaceUsesOfWith(I, I->getOperand(0), Worklist, L, LPM);
else // X & 0 -> 0
ReplaceUsesOfWith(I, I->getOperand(1), Worklist, L, LPM);
continue;
}
break;
case Instruction::Or:
if (isa<ConstantInt>(I->getOperand(0)) &&
// constant -> RHS
I->getOperand(0)->getType()->isIntegerTy(1))
cast<BinaryOperator>(I)->swapOperands();
if (ConstantInt *CB = dyn_cast<ConstantInt>(I->getOperand(1)))
if (CB->getType()->isIntegerTy(1)) {
if (CB->isOne()) // X | 1 -> 1
ReplaceUsesOfWith(I, I->getOperand(1), Worklist, L, LPM);
else // X | 0 -> X
ReplaceUsesOfWith(I, I->getOperand(0), Worklist, L, LPM);
continue;
}
break;
case Instruction::Br: {
BranchInst *BI = cast<BranchInst>(I);
if (BranchInst *BI = dyn_cast<BranchInst>(I)) {
if (BI->isUnconditional()) {
// If BI's parent is the only pred of the successor, fold the two blocks
// together.
@ -1061,13 +1031,13 @@ void LoopUnswitch::SimplifyCode(std::vector<Instruction*> &Worklist, Loop *L) {
LPM->deleteSimpleAnalysisValue(Succ, L);
Succ->eraseFromParent();
++NumSimplify;
break;
continue;
}
if (ConstantInt *CB = dyn_cast<ConstantInt>(BI->getCondition())){
// Conditional branch. Turn it into an unconditional branch, then
// remove dead blocks.
break; // FIXME: Enable.
continue; // FIXME: Enable.
DEBUG(dbgs() << "Folded branch: " << *BI);
BasicBlock *DeadSucc = BI->getSuccessor(CB->getZExtValue());
@ -1081,8 +1051,7 @@ void LoopUnswitch::SimplifyCode(std::vector<Instruction*> &Worklist, Loop *L) {
RemoveBlockIfDead(DeadSucc, Worklist, L);
}
break;
}
continue;
}
}
}