[WebAssembly] Fix fast-isel lowering illegal argument and return types.

For both argument and return types, promote illegal types like i24 to i32,
and if a type can't be easily promoted, clear out the signature before
bailing out, so avoid leaving it in a partially complete state.

Fixes PR37546.

llvm-svn: 332947
diff --git a/llvm/test/CodeGen/WebAssembly/fast-isel-i24.ll b/llvm/test/CodeGen/WebAssembly/fast-isel-i24.ll
index 48618e7d..10f1490 100644
--- a/llvm/test/CodeGen/WebAssembly/fast-isel-i24.ll
+++ b/llvm/test/CodeGen/WebAssembly/fast-isel-i24.ll
@@ -1,16 +1,28 @@
 ; RUN: llc < %s -O0
 ; PR36564
+; PR37546
 
 ; 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"
 
+; CHECK-LABEL: add:
+; CHECK-NEXT: .param  	i32, i32{{$}}
+; CHECK-NEXT: .result 	i32{{$}}
+; CHECK-NEXT: get_local	$push2=, 0{{$}}
+; CHECK-NEXT: get_local	$push1=, 1{{$}}
+; CHECK-NEXT: i32.add 	$push0=, $pop2, $pop1{{$}}
+; CHECK-NEXT: end_function
 define i24 @add(i24 %x, i24 %y) {
     %z = add i24 %x, %y
     ret i24 %z
 }
 
+; CHECK-LABEL: return_zero:
+; CHECK-NEXT: .result 	i32{{$}}
+; CHECK-NEXT: i32.const	$push0=, 0{{$}}
+; CHECK-NEXT: end_function
 define i24 @return_zero() {
     ret i24 0
 }
diff --git a/llvm/test/CodeGen/WebAssembly/fast-isel-i256.ll b/llvm/test/CodeGen/WebAssembly/fast-isel-i256.ll
new file mode 100644
index 0000000..a30ea35
--- /dev/null
+++ b/llvm/test/CodeGen/WebAssembly/fast-isel-i256.ll
@@ -0,0 +1,33 @@
+; RUN: llc < %s -O0
+; PR36564
+; PR37546
+
+; Test that fast-isel properly copes with i256 arguments and return types.
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+; CHECK-LABEL: add:
+; CHECK-NEXT: .param      i32, i64, i64, i64, i64, i64, i64, i64, i64{{$}}
+; CHECK-NOT:  .result
+; CHECK: end_function
+define i256 @add(i256 %x, i256 %y) {
+    %z = add i256 %x, %y
+    ret i256 %z
+}
+
+; CHECK-LABEL: return_zero:
+; CHECK-NEXT: .param      i32{{$}}
+; CHECK-NOT: .result
+; CHECK: end_function
+define i256 @return_zero() {
+    ret i256 0
+}
+
+; CHECK-LABEL: return_zero_with_params:
+; CHECK-NEXT: .param      i32, f32{{$}}
+; CHECK-NOT: .result
+; CHECK: end_function
+define i256 @return_zero_with_params(float %x) {
+    ret i256 0
+}