SCEV fix: Handle loop invariant loads.
Fixes PR11882: NULL dereference in ComputeLoadConstantCompareExitLimit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153480 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index 0c0ceeb..8b53979 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -4619,6 +4619,10 @@
Indexes.push_back(0);
}
+ // Loop-invariant loads may be a byproduct of loop optimization. Skip them.
+ if (!VarIdx)
+ return getCouldNotCompute();
+
// Okay, we know we have a (load (gep GV, 0, X)) comparison with a constant.
// Check to see if X is a loop variant variable value now.
const SCEV *Idx = getSCEV(VarIdx);
@@ -6845,7 +6849,7 @@
return ProperlyDominatesBlock;
case scCouldNotCompute:
llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
- default:
+ default:
llvm_unreachable("Unknown SCEV kind!");
}
}