When propagating equalities, eg replacing A with B in every basic block
dominated by Root, check that B is available throughout the scope. This
is obviously true (famous last words?) given the current logic, but the
check may be helpful if more complicated reasoning is added one day.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153323 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index ac80c48..8b79d27 100644
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -2001,6 +2001,9 @@
LVN = RVN;
}
}
+ assert((!isa<Instruction>(RHS) ||
+ DT->properlyDominates(cast<Instruction>(RHS)->getParent(), Root)) &&
+ "Instruction doesn't dominate scope!");
// If value numbering later deduces that an instruction in the scope is equal
// to 'LHS' then ensure it will be turned into 'RHS'.