Add intrinsic checkup on arguments number

src/librustc_typeck/check/intrinsic.rs

@@ -408,6 +408,13 @@ pub fn check_platform_intrinsic_type(ccx: &CrateCtxt,
                     let mut structural_to_nomimal = HashMap::new();
 
                     let sig = tcx.no_late_bound_regions(i_ty.ty.fn_sig()).unwrap();
+                    if intr.inputs.len() != sig.inputs.len() {
+                        span_err!(tcx.sess, it.span, E0444,
+                                  "platform-specific intrinsic has invalid number of \
+                                   arguments: found {}, expected {}",
+                                  intr.inputs.len(), sig.inputs.len());
+                        return
+                    }
                     let input_pairs = intr.inputs.iter().zip(&sig.inputs);
                     for (i, (expected_arg, arg)) in input_pairs.enumerate() {
                         match_intrinsic_type_to_type(tcx, &format!("argument {}", i + 1), it.span,

src/librustc_typeck/diagnostics.rs

@@ -3018,7 +3018,34 @@ PhantomData can also be used to express information about unused type
 parameters. You can read more about it in the API documentation:
 
 https://doc.rust-lang.org/std/marker/struct.PhantomData.html
-"##
+"##,
+
+E0444: r##"
+A platform-specific intrinsic function has wrong number of arguments.
+Erroneous code example:
+
+```
+#[repr(simd)]
+struct f64x2(f64, f64);
+
+extern "platform-intrinsic" {
+    fn x86_mm_movemask_pd(x: f64x2, y: f64x2, z: f64x2) -> i32;
+    // error: platform-specific intrinsic has invalid number of arguments
+}
+```
+
+Please refer to the function declaration to see if it corresponds
+with yours. Example:
+
+```
+#[repr(simd)]
+struct f64x2(f64, f64);
+
+extern "platform-intrinsic" {
+    fn x86_mm_movemask_pd(x: f64x2) -> i32; // ok!
+}
+```
+"##,
 
 }
 

src/test/compile-fail/intrinsic-invalid-number-of-arguments.rs

@@ -0,0 +1,24 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Test number of arguments in platform-specific intrinsic function
+// This is the error E0444
+
+#![feature(repr_simd, platform_intrinsics)]
+
+#[repr(simd)]
+struct f64x2(f64, f64);
+
+extern "platform-intrinsic" {
+    fn x86_mm_movemask_pd(x: f64x2, y: f64x2, z: f64x2) -> i32; //~ platform-specific intrinsic
+}
+
+pub fn main() {
+}