[WebAssembly] Teach fast-isel to gracefully recover from illegal return types.

Fixes PR36564.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@330215 91177308-0d34-0410-b5e6-96231b3b80d8

Author: Dan Gohman

lib/Target/WebAssembly/WebAssemblyFastISel.cpp

@@ -698,8 +698,12 @@ bool WebAssemblyFastISel::fastLowerArguments() {
   for (auto const &Arg : F->args())
     MFI->addParam(getLegalType(getSimpleType(Arg.getType())));
 
-  if (!F->getReturnType()->isVoidTy())
-    MFI->addResult(getLegalType(getSimpleType(F->getReturnType())));
+  if (!F->getReturnType()->isVoidTy()) {
+    MVT::SimpleValueType RetTy = getSimpleType(F->getReturnType());
+    if (RetTy == MVT::INVALID_SIMPLE_VALUE_TYPE)
+      return false;
+    MFI->addResult(getLegalType(RetTy));
+  }
 
   return true;
 }

test/CodeGen/WebAssembly/fast-isel-i24.ll

@@ -0,0 +1,16 @@
+; RUN: llc < %s -O0
+; PR36564
+
+; Test that fast-isel properly copes with i24 arguments and return types.
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown-wasm"
+
+define i24 @add(i24 %x, i24 %y) {
+    %z = add i24 %x, %y
+    ret i24 %z
+}
+
+define i24 @return_zero() {
+    ret i24 0
+}