Don't materialize on insertion block changes

src/Reactor/LLVMReactor.cpp

@@ -665,9 +665,7 @@ BasicBlock *Nucleus::getInsertBlock()
 
 void Nucleus::setInsertBlock(BasicBlock *basicBlock)
 {
-	//	assert(jit->builder->GetInsertBlock()->back().isTerminator());
-
-	Variable::materializeAll();
+	// assert(jit->builder->GetInsertBlock()->back().isTerminator());
 
 	jit->builder->SetInsertPoint(B(basicBlock));
 }

src/Reactor/Reactor.hpp

@@ -3519,6 +3519,11 @@ public:
 		falseBB = nullptr;
 		endBB = Nucleus::createBasicBlock();
 
+		// The conditional branch won't be appended until we've reached the 'end'
+		// basic block, so we must materialize all variables now (i.e. emit store
+		// instrutions to write them to memory).
+		Variable::materializeAll();
+
 		Nucleus::setInsertBlock(trueBB);
 	}
 
@@ -3526,6 +3531,8 @@ public:
 	{
 		Nucleus::createBr(endBB);
 
+		// Append the conditional branch instruction to the 'begin' basic block.
+		// Note that it's too late to materialize variables at this point.
 		Nucleus::setInsertBlock(beginBB);
 		Nucleus::createCondBr(condition, trueBB, falseBB ? falseBB : endBB);
 

src/Reactor/SubzeroReactor.cpp

@@ -1122,9 +1122,7 @@ BasicBlock *Nucleus::getInsertBlock()
 
 void Nucleus::setInsertBlock(BasicBlock *basicBlock)
 {
-	//	ASSERT(::basicBlock->getInsts().back().getTerminatorEdges().size() >= 0 && "Previous basic block must have a terminator");
-
-	Variable::materializeAll();
+	// ASSERT(::basicBlock->getInsts().back().getTerminatorEdges().size() >= 0 && "Previous basic block must have a terminator");
 
 	::basicBlock = basicBlock;
 }