make LazyValueInfo analyze the default case of switch statements (we know that in the default branch the value cannot be any of the switch cases)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159353 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/LazyValueInfo.cpp b/lib/Analysis/LazyValueInfo.cpp
index 83786dd..9140786 100644
--- a/lib/Analysis/LazyValueInfo.cpp
+++ b/lib/Analysis/LazyValueInfo.cpp
@@ -835,24 +835,23 @@
// 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 (SI->getCondition() == Val) {
- // We don't know anything in the default case.
- if (SI->getDefaultDest() == BBTo) {
- Result.markOverdefined();
- return true;
- }
-
- unsigned BitWidth = Val->getType()->getIntegerBitWidth();
- ConstantRange EdgesVals(BitWidth, false/*isFullSet*/);
- for (SwitchInst::CaseIt i = SI->case_begin(), e = SI->case_end();
- i != e; ++i) {
- if (i.getCaseSuccessor() != BBTo) continue;
- ConstantRange EdgeVal(i.getCaseValue()->getValue());
+ if (SI->getCondition() != Val)
+ return false;
+
+ bool DefaultCase = SI->getDefaultDest() == BBTo;
+ unsigned BitWidth = Val->getType()->getIntegerBitWidth();
+ ConstantRange EdgesVals(BitWidth, DefaultCase/*isFullSet*/);
+
+ for (SwitchInst::CaseIt i = SI->case_begin(), e = SI->case_end();
+ i != e; ++i) {
+ ConstantRange EdgeVal(i.getCaseValue()->getValue());
+ if (DefaultCase)
+ EdgesVals = EdgesVals.difference(EdgeVal);
+ else if (i.getCaseSuccessor() == BBTo)
EdgesVals = EdgesVals.unionWith(EdgeVal);
- }
- Result = LVILatticeVal::getRange(EdgesVals);
- return true;
}
+ Result = LVILatticeVal::getRange(EdgesVals);
+ return true;
}
return false;
}