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Eliminate unnecessary zext/trunc stuffs.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35737 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Zhou Sheng 2007-04-07 17:12:38 +00:00
parent a3b12ddade
commit 8342836d70
1 changed files with 10 additions and 14 deletions
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24
lib/Analysis/ScalarEvolution.cpp
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@ -1147,7 +1147,7 @@ namespace {
SCEVHandle ComputeIterationCount(const Loop *L); SCEVHandle ComputeIterationCount(const Loop *L);
/// ComputeLoadConstantCompareIterationCount - Given an exit condition of /// ComputeLoadConstantCompareIterationCount - Given an exit condition of
/// 'setcc load X, cst', try to se if we can compute the trip count. /// 'setcc load X, cst', try to see if we can compute the trip count.
SCEVHandle ComputeLoadConstantCompareIterationCount(LoadInst *LI, SCEVHandle ComputeLoadConstantCompareIterationCount(LoadInst *LI,
Constant *RHS, Constant *RHS,
const Loop *L, const Loop *L,
@ -1342,21 +1342,19 @@ static APInt GetConstantFactor(SCEVHandle S) {
} }
if (SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(S)) { if (SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(S)) {
APInt Mask(cast<IntegerType>(T->getType())->getMask()); return GetConstantFactor(T->getOperand()).trunc(
APInt GCF(GetConstantFactor(T->getOperand())); cast<IntegerType>(T->getType())->getBitWidth());
Mask.zextOrTrunc(GCF.getBitWidth());
return GCF & Mask;
} }
if (SCEVZeroExtendExpr *E = dyn_cast<SCEVZeroExtendExpr>(S)) if (SCEVZeroExtendExpr *E = dyn_cast<SCEVZeroExtendExpr>(S))
return GetConstantFactor(E->getOperand()); return GetConstantFactor(E->getOperand()).zext(
cast<IntegerType>(E->getType())->getBitWidth());
if (SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(S)) { if (SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(S)) {
// The result is the min of all operands. // The result is the min of all operands.
APInt Res = GetConstantFactor(A->getOperand(0)); APInt Res(GetConstantFactor(A->getOperand(0)));
for (unsigned i = 1, e = A->getNumOperands(); for (unsigned i = 1, e = A->getNumOperands();
i != e && Res.ugt(APInt(Res.getBitWidth(),1)); ++i) { i != e && Res.ugt(APInt(Res.getBitWidth(),1)); ++i) {
APInt Tmp(GetConstantFactor(A->getOperand(i))); APInt Tmp(GetConstantFactor(A->getOperand(i)));
Tmp.zextOrTrunc(Res.getBitWidth());
Res = APIntOps::umin(Res, Tmp); Res = APIntOps::umin(Res, Tmp);
} }
return Res; return Res;
@ -1364,10 +1362,9 @@ static APInt GetConstantFactor(SCEVHandle S) {
if (SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(S)) { if (SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(S)) {
// The result is the product of all the operands. // The result is the product of all the operands.
APInt Res = GetConstantFactor(M->getOperand(0)); APInt Res(GetConstantFactor(M->getOperand(0)));
for (unsigned i = 1, e = M->getNumOperands(); i != e; ++i) { for (unsigned i = 1, e = M->getNumOperands(); i != e; ++i) {
APInt Tmp(GetConstantFactor(M->getOperand(i))); APInt Tmp(GetConstantFactor(M->getOperand(i)));
Tmp.zextOrTrunc(Res.getBitWidth());
Res *= Tmp; Res *= Tmp;
} }
return Res; return Res;
@ -1377,11 +1374,10 @@ static APInt GetConstantFactor(SCEVHandle S) {
// For now, we just handle linear expressions. // For now, we just handle linear expressions.
if (A->getNumOperands() == 2) { if (A->getNumOperands() == 2) {
// We want the GCD between the start and the stride value. // We want the GCD between the start and the stride value.
APInt Start = GetConstantFactor(A->getOperand(0)); APInt Start(GetConstantFactor(A->getOperand(0)));
if (Start == 1) if (Start == 1)
return APInt(A->getBitWidth(),1); return Start;
APInt Stride = GetConstantFactor(A->getOperand(1)); APInt Stride(GetConstantFactor(A->getOperand(1)));
Start.zextOrTrunc(Stride.getBitWidth());
return APIntOps::GreatestCommonDivisor(Start, Stride); return APIntOps::GreatestCommonDivisor(Start, Stride);
} }
} }