Factor out code for computing umin and smin for SCEV expressions into

helper functions. Based on a patch by Nick Lewycky.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73869 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2009-06-22 03:18:45 +00:00
parent 2cf5f14f20
commit f9a9a9928c
2 changed files with 16 additions and 7 deletions

View File

@ -494,6 +494,8 @@ namespace llvm {
SCEVHandle getSMaxExpr(SmallVectorImpl<SCEVHandle> &Operands);
SCEVHandle getUMaxExpr(const SCEVHandle &LHS, const SCEVHandle &RHS);
SCEVHandle getUMaxExpr(SmallVectorImpl<SCEVHandle> &Operands);
SCEVHandle getSMinExpr(const SCEVHandle &LHS, const SCEVHandle &RHS);
SCEVHandle getUMinExpr(const SCEVHandle &LHS, const SCEVHandle &RHS);
SCEVHandle getUnknown(Value *V);
SCEVHandle getCouldNotCompute();

View File

@ -1903,6 +1903,18 @@ ScalarEvolution::getUMaxExpr(SmallVectorImpl<SCEVHandle> &Ops) {
return Result;
}
SCEVHandle ScalarEvolution::getSMinExpr(const SCEVHandle &LHS,
const SCEVHandle &RHS) {
// ~smax(~x, ~y) == smin(x, y).
return getNotSCEV(getSMaxExpr(getNotSCEV(LHS), getNotSCEV(RHS)));
}
SCEVHandle ScalarEvolution::getUMinExpr(const SCEVHandle &LHS,
const SCEVHandle &RHS) {
// ~umax(~x, ~y) == umin(x, y)
return getNotSCEV(getUMaxExpr(getNotSCEV(LHS), getNotSCEV(RHS)));
}
SCEVHandle ScalarEvolution::getUnknown(Value *V) {
if (ConstantInt *CI = dyn_cast<ConstantInt>(V))
return getConstant(CI);
@ -2644,10 +2656,7 @@ SCEVHandle ScalarEvolution::createSCEV(Value *V) {
if (LHS == U->getOperand(1) && RHS == U->getOperand(2))
return getSMaxExpr(getSCEV(LHS), getSCEV(RHS));
else if (LHS == U->getOperand(2) && RHS == U->getOperand(1))
// ~smax(~x, ~y) == smin(x, y).
return getNotSCEV(getSMaxExpr(
getNotSCEV(getSCEV(LHS)),
getNotSCEV(getSCEV(RHS))));
return getSMinExpr(getSCEV(LHS), getSCEV(RHS));
break;
case ICmpInst::ICMP_ULT:
case ICmpInst::ICMP_ULE:
@ -2658,9 +2667,7 @@ SCEVHandle ScalarEvolution::createSCEV(Value *V) {
if (LHS == U->getOperand(1) && RHS == U->getOperand(2))
return getUMaxExpr(getSCEV(LHS), getSCEV(RHS));
else if (LHS == U->getOperand(2) && RHS == U->getOperand(1))
// ~umax(~x, ~y) == umin(x, y)
return getNotSCEV(getUMaxExpr(getNotSCEV(getSCEV(LHS)),
getNotSCEV(getSCEV(RHS))));
return getUMinExpr(getSCEV(LHS), getSCEV(RHS));
break;
case ICmpInst::ICMP_NE:
// n != 0 ? n : 1 -> umax(n, 1)