[WebAssembly] Lower to target-independent saturating add

[tlively]

Summary

Goes along with D53721.

lib/CodeGen/CGBuiltin.cpp

Value *CodeGenFunction::EmitWebAssemblyBuiltinExpr(unsigned BuiltinID,
   case WebAssembly::BI__builtin_wasm_sub_saturate_s_i8x16:
   case WebAssembly::BI__builtin_wasm_sub_saturate_u_i8x16:
   case WebAssembly::BI__builtin_wasm_sub_saturate_s_i16x8:
   case WebAssembly::BI__builtin_wasm_sub_saturate_u_i16x8: {
     unsigned IntNo;
     switch (BuiltinID) {
     case WebAssembly::BI__builtin_wasm_add_saturate_s_i8x16:
     case WebAssembly::BI__builtin_wasm_add_saturate_s_i16x8:
-      IntNo = Intrinsic::wasm_add_saturate_signed;
+      IntNo = Intrinsic::sadd_sat;
       break;
     case WebAssembly::BI__builtin_wasm_add_saturate_u_i8x16:
     case WebAssembly::BI__builtin_wasm_add_saturate_u_i16x8:
-      IntNo = Intrinsic::wasm_add_saturate_unsigned;
+      IntNo = Intrinsic::uadd_sat;
       break;
     case WebAssembly::BI__builtin_wasm_sub_saturate_s_i8x16:
     case WebAssembly::BI__builtin_wasm_sub_saturate_s_i16x8:
       IntNo = Intrinsic::wasm_sub_saturate_signed;
       break;
     case WebAssembly::BI__builtin_wasm_sub_saturate_u_i8x16:
     case WebAssembly::BI__builtin_wasm_sub_saturate_u_i16x8:
       IntNo = Intrinsic::wasm_sub_saturate_unsigned;

test/CodeGen/builtins-wasm.c

 f64x2 replace_lane_f64x2(f64x2 v, double x) {
   return __builtin_wasm_replace_lane_f64x2(v, 1, x);
   // WEBASSEMBLY: insertelement <2 x double> %v, double %x, i32 1
   // WEBASSEMBLY-NEXT: ret
 }
 
 i8x16 add_saturate_s_i8x16(i8x16 x, i8x16 y) {
   return __builtin_wasm_add_saturate_s_i8x16(x, y);
-  // WEBASSEMBLY: call <16 x i8> @llvm.wasm.add.saturate.signed.v16i8(
+  // WEBASSEMBLY: call <16 x i8> @llvm.sadd.sat.v16i8(
   // WEBASSEMBLY-SAME: <16 x i8> %x, <16 x i8> %y)
   // WEBASSEMBLY-NEXT: ret
 }
 
 i8x16 add_saturate_u_i8x16(i8x16 x, i8x16 y) {
   return __builtin_wasm_add_saturate_u_i8x16(x, y);
-  // WEBASSEMBLY: call <16 x i8> @llvm.wasm.add.saturate.unsigned.v16i8(
+  // WEBASSEMBLY: call <16 x i8> @llvm.uadd.sat.v16i8(
   // WEBASSEMBLY-SAME: <16 x i8> %x, <16 x i8> %y)
   // WEBASSEMBLY-NEXT: ret
 }
 
 i16x8 add_saturate_s_i16x8(i16x8 x, i16x8 y) {
   return __builtin_wasm_add_saturate_s_i16x8(x, y);
-  // WEBASSEMBLY: call <8 x i16> @llvm.wasm.add.saturate.signed.v8i16(
+  // WEBASSEMBLY: call <8 x i16> @llvm.sadd.sat.v8i16(
   // WEBASSEMBLY-SAME: <8 x i16> %x, <8 x i16> %y)
   // WEBASSEMBLY-NEXT: ret
 }
 
 i16x8 add_saturate_u_i16x8(i16x8 x, i16x8 y) {
   return __builtin_wasm_add_saturate_u_i16x8(x, y);
-  // WEBASSEMBLY: call <8 x i16> @llvm.wasm.add.saturate.unsigned.v8i16(
+  // WEBASSEMBLY: call <8 x i16> @llvm.uadd.sat.v8i16(
   // WEBASSEMBLY-SAME: <8 x i16> %x, <8 x i16> %y)
   // WEBASSEMBLY-NEXT: ret
 }
 
 i8x16 sub_saturate_s_i8x16(i8x16 x, i8x16 y) {
   return __builtin_wasm_sub_saturate_s_i8x16(x, y);
   // WEBASSEMBLY: call <16 x i8> @llvm.wasm.sub.saturate.signed.v16i8(
   // WEBASSEMBLY-SAME: <16 x i8> %x, <16 x i8> %y)