Add support for Vector Truncate on PowerPC

Author: lu-zero

src/etc/platform-intrinsics/powerpc.json

@@ -255,6 +255,13 @@
             "ret": "f32",
             "args": ["0"]
         },
+        {
+            "intrinsic": "trunc",
+            "width": [128],
+            "llvm": "vrfiz",
+            "ret": "f32",
+            "args": ["0"]
+        },
         {
             "intrinsic": "loge",
             "width": [128],

src/librustc_platform_intrinsics/powerpc.rs

@@ -422,6 +422,11 @@ pub fn find(name: &str) -> Option<Intrinsic> {
             output: &::F32x4,
             definition: Named("llvm.ppc.altivec.vrfin")
         },
+        "_vec_trunc" => Intrinsic {
+            inputs: { static INPUTS: [&'static Type; 1] = [&::F32x4]; &INPUTS },
+            output: &::F32x4,
+            definition: Named("llvm.ppc.altivec.vrfiz")
+        },
         "_vec_loge" => Intrinsic {
             inputs: { static INPUTS: [&'static Type; 1] = [&::F32x4]; &INPUTS },
             output: &::F32x4,