A bit of cleanup and applied Yuri's suggested changes

Author: DutChen18

llvm/lib/CheerpUtils/PointerAnalyzer.cpp

@@ -642,6 +642,7 @@ PointerKindWrapper& PointerUsageVisitor::visitValue(PointerKindWrapper& ret, con
 		case Intrinsic::cheerp_downcast:
 		case Intrinsic::cheerp_upcast_collapsed:
 		case Intrinsic::cheerp_cast_user:
+			break;
 		case Intrinsic::cheerp_typed_ptrcast:
 			if (isa<IntToPtrInst>(intrinsic->getArgOperand(0)))
 				return CacheAndReturn(visitValue(ret, intrinsic->getArgOperand(0), false));

llvm/lib/CheerpWriter/CheerpWriter.cpp

@@ -1622,9 +1622,9 @@ void CheerpWriter::compileEqualPointersComparison(const llvm::Value* lhs, const
 				isInlineable(*cast<Instruction>(lhs), PA));
 		assert(rhsKind != COMPLETE_OBJECT || !isa<Instruction>(rhs) ||
 				isInlineable(*cast<Instruction>(rhs), PA));
-		compilePointerBase(lhs, false, true);
+		compilePointerBase(lhs, /*forEscapingPointer*/false, /*useGPET*/true);
 		stream << compareString;
-		compilePointerBase(rhs, false, true);
+		compilePointerBase(rhs, /*forEscapingPointer*/false, /*useGPET*/true);
 		stream << joinString;
 		compilePointerOffset(lhs, COMPARISON);
 		stream << compareString;
@@ -1634,9 +1634,9 @@ void CheerpWriter::compileEqualPointersComparison(const llvm::Value* lhs, const
 	{
 		assert(lhsKind != COMPLETE_OBJECT);
 		assert(rhsKind != COMPLETE_OBJECT);
-		compilePointerBase(lhs, false, true);
+		compilePointerBase(lhs, /*forEscapingPointer*/false, /*useGPET*/true);
 		stream << compareString;
-		compilePointerBase(rhs, false, true);
+		compilePointerBase(rhs, /*forEscapingPointer*/false, /*useGPET*/true);
 		stream << joinString;
 		compilePointerOffset(lhs, COMPARISON);
 		stream << compareString;
@@ -1732,7 +1732,6 @@ void CheerpWriter::compileCompleteObject(const Value* p, const Value* offset)
 		return;
 	}
 
-
 	const llvm::Instruction* I = dyn_cast<Instruction>(p);
 	if (I && !isInlineable(*I, PA) &&
 		(isGEP(I) || isBitCast(I)) && PA.getPointerKindAssert(I) == COMPLETE_OBJECT)
@@ -2017,6 +2016,11 @@ void CheerpWriter::compilePointerBase(const Value* p, bool forEscapingPointer, b
 
 	POINTER_KIND kind = PA.getPointerKind(p);
 
+	// This condition is true if we can safely pass a nullptr element type to compilePointerBaseType.
+	// The logic should work as follows:
+	// 1. if kind == RAW, it is not safe to pass nullptr
+	// 2. if kind == CONSTANT, it is not safe to pass nullptr *unless* it is a null pointer constant
+	// 3. otherwise, it is safe to pass nullptr
 	if (kind != RAW && (kind != CONSTANT || isa<ConstantPointerNull>(p)))
 	{
 		// point element type is not used in this case, so it can be null
@@ -2032,12 +2036,13 @@ void CheerpWriter::compilePointerBase(const Value* p, bool forEscapingPointer, b
 			compilePointerBaseTyped(p, T, forEscapingPointer);
 		else
 		{
+#ifndef NDEBUG
 			p->dump();
 			if (const Instruction* i = dyn_cast<Instruction>(p))
 				i->getParent()->getParent()->dump();
+#endif
 			llvm::report_fatal_error("Missing typed ptrcast intrinsic and no GPET allowed");
 		}
-
 	}
 }