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Add a SCEV class and supporting code for sign-extend expressions.

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This created an ambiguity for expandInTy to decide when to use
sign-extension or zero-extension, but it turns out that most of its callers
don't actually need a type conversion, now that LLVM types don't have
explicit signedness. Drop expandInTy in favor of plain expand, and change
the few places that actually need a type conversion to do it themselves.

llvm-svn: 37591
This commit is contained in:
Dan Gohman
2007-06-15 14:38:12 +00:00
parent 92fb5453c3
commit cb9e09ad57
6 changed files with 139 additions and 58 deletions
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13
llvm/lib/Analysis/ScalarEvolutionExpander.cpp
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@@ -93,18 +93,17 @@ Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode, Value *LHS,
}
Value *SCEVExpander::visitMulExpr(SCEVMulExpr *S) {
const Type *Ty = S->getType();
int FirstOp = 0; // Set if we should emit a subtract.
if (SCEVConstant *SC = dyn_cast<SCEVConstant>(S->getOperand(0)))
if (SC->getValue()->isAllOnesValue())
FirstOp = 1;
int i = S->getNumOperands()-2;
Value *V = expandInTy(S->getOperand(i+1), Ty);
Value *V = expand(S->getOperand(i+1));
// Emit a bunch of multiply instructions
for (; i >= FirstOp; --i)
V = InsertBinop(Instruction::Mul, V, expandInTy(S->getOperand(i), Ty),
V = InsertBinop(Instruction::Mul, V, expand(S->getOperand(i)),
InsertPt);
// -1 * ... ---> 0 - ...
if (FirstOp == 1)
@@ -122,10 +121,10 @@ Value *SCEVExpander::visitAddRecExpr(SCEVAddRecExpr *S) {
// {X,+,F} --> X + {0,+,F}
if (!isa<SCEVConstant>(S->getStart()) ||
!cast<SCEVConstant>(S->getStart())->getValue()->isZero()) {
Value *Start = expandInTy(S->getStart(), Ty);
Value *Start = expand(S->getStart());
std::vector<SCEVHandle> NewOps(S->op_begin(), S->op_end());
NewOps[0] = SCEVUnknown::getIntegerSCEV(0, Ty);
Value *Rest = expandInTy(SCEVAddRecExpr::get(NewOps, L), Ty);
Value *Rest = expand(SCEVAddRecExpr::get(NewOps, L));
// FIXME: look for an existing add to use.
return InsertBinop(Instruction::Add, Rest, Start, InsertPt);
@@ -164,7 +163,7 @@ Value *SCEVExpander::visitAddRecExpr(SCEVAddRecExpr *S) {
// If this is a simple linear addrec, emit it now as a special case.
if (S->getNumOperands() == 2) { // {0,+,F} --> i*F
Value *F = expandInTy(S->getOperand(1), Ty);
Value *F = expand(S->getOperand(1));
// IF the step is by one, just return the inserted IV.
if (ConstantInt *CI = dyn_cast<ConstantInt>(F))
@@ -201,5 +200,5 @@ Value *SCEVExpander::visitAddRecExpr(SCEVAddRecExpr *S) {
SCEVHandle V = S->evaluateAtIteration(IH);
//cerr << "Evaluated: " << *this << "\n to: " << *V << "\n";
return expandInTy(V, Ty);
return expand(V);
}