Index: lib/Transforms/IPO/LowerTypeTests.cpp
===================================================================
--- lib/Transforms/IPO/LowerTypeTests.cpp
+++ lib/Transforms/IPO/LowerTypeTests.cpp
@@ -827,30 +827,36 @@
       ConstantArray::get(JumpTableType, JumpTableEntries));
 }
 
-// Assign a dummy layout based using an incrementing counter, and store this as
-// metadata. During generation of the indexed indirect function call table, the
-// backend will ensure that the appropriate indexes are used.
+// Assign each disjoint set to a different indirect function call table using
+// an incrementing counter. Then, eliminate explicit type tests. This is safe
+// because the type homogeneity of each disjoint set is checked at load-time.
+// Additionally, calls to out of bounds table entries will trap at runtime.
 void LowerTypeTests::buildBitSetsFromFunctionsWASM(
     ArrayRef<Metadata *> TypeIds, ArrayRef<Function *> Functions) {
   assert(!Functions.empty());
 
-  // Build a dummy layout.
-  DenseMap<GlobalObject *, uint64_t> GlobalLayout;
-  for (Function *F : Functions)
-    GlobalLayout[F] = IndirectIndex++;
+  // Manually lower type tests by eliminating explicit type tests.
+  for (Metadata *TypeId : TypeIds) {
+    // Replace each type test with true, and let simplifycfg remove the branch.
+    for (CallInst *TypeTest : TypeTestCallSites[TypeId]) {
+      ConstantInt *True = ConstantInt::getTrue(TypeTest->getContext());
+      TypeTest->replaceAllUsesWith(True);
+      TypeTest->eraseFromParent();
 
-  // Pass a NULL pointer as the subtracted "jump table" offset.
-  lowerTypeTestCalls(TypeIds,
-                     ConstantPointerNull::get(cast<PointerType>(Int32PtrTy)),
-                     GlobalLayout);
+      ++NumTypeTestCallsLowered;
+    }
+  }
 
   // Generate metadata for the indirect function indexes.
-  for (const auto &P : GlobalLayout) {
-    MDNode *MD = MDNode::get(P.first->getContext(),
+  for (const auto F : Functions) {
+    MDNode *MD = MDNode::get(F->getContext(),
                              ArrayRef<Metadata *>(ConstantAsMetadata::get(
-                                 ConstantInt::get(Int64Ty, P.second))));
-    cast<Function>(P.first)->setMetadata("wasm.index", MD);
+                                 ConstantInt::get(Int64Ty, IndirectIndex))));
+    F->setMetadata("wasm.index", MD);
   }
+
+  // Increment the counter to put each disjoint set in a different table.
+  IndirectIndex += 1;
 }
 
 void LowerTypeTests::buildBitSetsFromDisjointSet(
Index: test/Transforms/LowerTypeTests/function-disjoint.ll
===================================================================
--- test/Transforms/LowerTypeTests/function-disjoint.ll
+++ test/Transforms/LowerTypeTests/function-disjoint.ll
@@ -31,12 +31,14 @@
 
 define i1 @foo(i8* %p) {
   ; X64: icmp eq i64 {{.*}}, ptrtoint ([1 x <{ i8, i32, i8, i8, i8 }>]* @[[JT0]] to i64)
-  ; WASM32: icmp eq i64 {{.*}}, 0
+  ; WASM32-NOT: icmp ult i64 {{.*}}, 0
   %x = call i1 @llvm.type.test(i8* %p, metadata !"typeid1")
   ; X64: icmp eq i64 {{.*}}, ptrtoint ([1 x <{ i8, i32, i8, i8, i8 }>]* @[[JT1]] to i64)
-  ; WASM32: icmp eq i64 {{.*}}, 1
+  ; WASM32-NOT: icmp ult i64 {{.*}}, 1
   %y = call i1 @llvm.type.test(i8* %p, metadata !"typeid2")
   %z = add i1 %x, %y
+  ; WASM32-NOT: br i1 {{.*}} label %cont, label %trap
+  ; WASM32: add i1 true, true
   ret i1 %z
 }
 
Index: test/Transforms/LowerTypeTests/function-ext.ll
===================================================================
--- test/Transforms/LowerTypeTests/function-ext.ll
+++ test/Transforms/LowerTypeTests/function-ext.ll
@@ -12,7 +12,8 @@
 
 define i1 @bar(i8* %ptr) {
   ; X64: icmp eq i64 {{.*}}, ptrtoint ([1 x <{ i8, i32, i8, i8, i8 }>]* @[[JT]] to i64)
-  ; WASM32: icmp eq i64 {{.*}}, 0
+  ; WASM32-NOT: icmp eq i64 {{.*}}, 0
+  ; WASM32: ret i1 true
   %p = call i1 @llvm.type.test(i8* %ptr, metadata !"void")
   ret i1 %p
 }
Index: test/Transforms/LowerTypeTests/function.ll
===================================================================
--- test/Transforms/LowerTypeTests/function.ll
+++ test/Transforms/LowerTypeTests/function.ll
@@ -12,13 +12,13 @@
 ; X64: @g = alias void (), bitcast (<{ i8, i32, i8, i8, i8 }>* getelementptr inbounds ([2 x <{ i8, i32, i8, i8, i8 }>], [2 x <{ i8, i32, i8, i8, i8 }>]* @[[JT]], i64 0, i64 1) to void ()*)
 
 ; X64: define private void @[[FNAME]]()
-; WASM32: define void @f() !type !{{[0-9]+}} !wasm.index ![[I0:[0-9]+]]
+; WASM32: define void @f() !type !{{[0-9]+}} !wasm.index ![[I:[0-9]+]]
 define void @f() !type !0 {
   ret void
 }
 
 ; X64: define private void @[[GNAME]]()
-; WASM32: define void @g() !type !{{[0-9]+}} !wasm.index ![[I1:[0-9]+]]
+; WASM32: define void @g() !type !{{[0-9]+}} !wasm.index ![[I]]
 define void @g() !type !0 {
   ret void
 }
@@ -29,11 +29,12 @@
 
 define i1 @foo(i8* %p) {
   ; X64: sub i64 {{.*}}, ptrtoint ([2 x <{ i8, i32, i8, i8, i8 }>]* @[[JT]] to i64)
-  ; WASM32: sub i64 {{.*}}, 0
-  ; WASM32: icmp ult i64 {{.*}}, 2
+  ; WASM32-NOT: sub i64 {{.*}}, 0
+  ; WASM32-NOT: icmp ult i64 {{.*}}, 2
+  ; WASM32-NOT: br i1 {{.*}} label %cont, label %trap
+  ; WASM32: ret i1 true
   %x = call i1 @llvm.type.test(i8* %p, metadata !"typeid1")
   ret i1 %x
 }
 
-; WASM32: ![[I0]] = !{i64 0}
-; WASM32: ![[I1]] = !{i64 1}
+; WASM32: ![[I]] = !{i64 0}