Add support for Vector Multiply Add Saturated on PowerPC

Author: lu-zero

src/etc/platform-intrinsics/powerpc.json

@@ -156,6 +156,13 @@
             "llvm": "vupkh{1.kind}{1.data_type_short}",
             "ret": "s(16-32)",
             "args": ["0N"]
+        },
+        {
+            "intrinsic": "madds",
+            "width": [128],
+            "llvm": "vmhaddshs",
+            "ret": "s16",
+            "args": ["0", "0", "0"]
         }
     ]
 }

src/librustc_platform_intrinsics/powerpc.rs

@@ -337,6 +337,11 @@ pub fn find(name: &str) -> Option<Intrinsic> {
             output: &::I32x4,
             definition: Named("llvm.ppc.altivec.vupkhsh")
         },
+        "_vec_madds" => Intrinsic {
+            inputs: { static INPUTS: [&'static Type; 3] = [&::I16x8, &::I16x8, &::I16x8]; &INPUTS },
+            output: &::I16x8,
+            definition: Named("llvm.ppc.altivec.vmhaddshs")
+        },
         _ => return None,
     })
 }