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Remove incorrect and poorly tested code for trying to reason about values on default edges of 

switches.  Just return the conservatively correct answer.

llvm-svn: 112876
This commit is contained in:
Owen Anderson 2010-09-02 22:16:52 +00:00
parent 56291f7e53
commit 2912df072d
1 changed files with 2 additions and 16 deletions
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18
llvm/lib/Analysis/LazyValueInfo.cpp
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@ -670,25 +670,11 @@ LVILatticeVal LVIQuery::getEdgeValue(BasicBlock *BBFrom, BasicBlock *BBTo) {
// If the edge was formed by a switch on the value, then we may know exactly
// what it is.
if (SwitchInst *SI = dyn_cast<SwitchInst>(BBFrom->getTerminator())) {
// If BBTo is the default destination of the switch, we know that it
// doesn't have the same value as any of the cases.
if (SI->getCondition() == Val) {
// We don't know anything in the default case.
if (SI->getDefaultDest() == BBTo) {
const IntegerType *IT = cast<IntegerType>(Val->getType());
ConstantRange CR(IT->getBitWidth());
for (unsigned i = 1, e = SI->getNumSuccessors(); i != e; ++i) {
const APInt CaseVal = SI->getCaseValue(i)->getValue();
ConstantRange CaseRange(CaseVal, CaseVal+1);
CaseRange = CaseRange.inverse();
CR = CR.intersectWith(CaseRange);
}
LVILatticeVal Result;
if (CR.isFullSet() || CR.isEmptySet())
Result.markOverdefined();
else
Result.markConstantRange(CR);
Result.markOverdefined();
return Result;
}