Add a new helper function to IVUsers for returning the "canonical"

form of an expression. This is the expression without the
post-increment adjustment made, which is useful in determining
which registers will be used by the expansion.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93921 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2010-01-19 21:55:32 +00:00
parent 8e1aa8edec
commit bafbbdde38
2 changed files with 18 additions and 0 deletions

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@ -212,6 +212,11 @@ public:
/// value of the OperandValToReplace of the given IVStrideUse.
const SCEV *getReplacementExpr(const IVStrideUse &U) const;
/// getCanonicalExpr - Return a SCEV expression which computes the
/// value of the SCEV of the given IVStrideUse, ignoring the
/// isUseOfPostIncrementedValue flag.
const SCEV *getCanonicalExpr(const IVStrideUse &U) const;
void print(raw_ostream &OS, const Module* = 0) const;
/// dump - This method is used for debugging.

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@ -333,6 +333,19 @@ const SCEV *IVUsers::getReplacementExpr(const IVStrideUse &U) const {
return RetVal;
}
/// getCanonicalExpr - Return a SCEV expression which computes the
/// value of the SCEV of the given IVStrideUse, ignoring the
/// isUseOfPostIncrementedValue flag.
const SCEV *IVUsers::getCanonicalExpr(const IVStrideUse &U) const {
// Start with zero.
const SCEV *RetVal = SE->getIntegerSCEV(0, U.getParent()->Stride->getType());
// Create the basic add recurrence.
RetVal = SE->getAddRecExpr(RetVal, U.getParent()->Stride, L);
// Add the offset in a separate step, because it may be loop-variant.
RetVal = SE->getAddExpr(RetVal, U.getOffset());
return RetVal;
}
void IVUsers::print(raw_ostream &OS, const Module *M) const {
OS << "IV Users for loop ";
WriteAsOperand(OS, L->getHeader(), false);