Don't cache PHI exit values from exhaustive evaluations, because

an individual exhaustive evaluation reflects only the exit value
implied by an individual exit, which may differ from the actual
exit value of the loop if there are other exits. This fixes PR4477.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74447 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/ScalarEvolution.cpp

@@ -3521,7 +3521,6 @@ ScalarEvolution::ComputeBackedgeTakenCountExhaustively(const Loop *L,
     if (!CondVal) return getCouldNotCompute();
 
     if (CondVal->getValue() == uint64_t(ExitWhen)) {
-      ConstantEvolutionLoopExitValue[PN] = PHIVal;
       ++NumBruteForceTripCountsComputed;
       return getConstant(Type::Int32Ty, IterationNum);
     }