Auto merge of #32649 - Amanieu:intrinsic_monomorphization_assert, r=eddyb

Fix LLVM assert when handling bad intrinsic monomorphizations

Passing an invalid type to certain intrinsics would trigger an LLVM assert even though the invalid type was caught by the compiler.

r? @eddyb

src/librustc_trans/intrinsic.rs

@@ -658,7 +658,7 @@ pub fn trans_intrinsic_call<'a, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
                         tcx.sess, span,
                         &format!("invalid monomorphization of `{}` intrinsic: \
                                   expected basic integer type, found `{}`", name, sty));
-                        C_null(llret_ty)
+                        C_nil(ccx)
                 }
             }
 
@@ -681,7 +681,7 @@ pub fn trans_intrinsic_call<'a, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
                         tcx.sess, span,
                         &format!("invalid monomorphization of `{}` intrinsic: \
                                   expected basic float type, found `{}`", name, sty));
-                        C_null(llret_ty)
+                        C_nil(ccx)
                 }
             }
 
@@ -1475,7 +1475,7 @@ fn generic_simd_intrinsic<'blk, 'tcx, 'a>
         ($cond: expr, $($fmt: tt)*) => {
             if !$cond {
                 emit_error!($($fmt)*);
-                return C_null(llret_ty)
+                return C_nil(bcx.ccx())
             }
         }
     }

src/test/compile-fail/bad-intrinsic-monomorphization.rs

@@ -0,0 +1,44 @@
+// Copyright 2016 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.
+
+#![feature(repr_simd, platform_intrinsics, rustc_attrs, core_intrinsics)]
+#![allow(warnings)]
+
+// Bad monomorphizations could previously cause LLVM asserts even though the
+// error was caught in the compiler.
+
+extern "platform-intrinsic" {
+    fn simd_add<T>(x: T, y: T) -> T;
+}
+
+use std::intrinsics;
+
+#[derive(Copy, Clone)]
+struct Foo(i64);
+
+#[rustc_no_mir] // FIXME #27840 MIR doesn't provide precise spans for calls.
+unsafe fn test_cttz(v: Foo) -> Foo {
+    intrinsics::cttz(v)
+    //~^ ERROR `cttz` intrinsic: expected basic integer type, found `Foo`
+}
+
+#[rustc_no_mir] // FIXME #27840 MIR doesn't provide precise spans for calls.
+unsafe fn test_fadd_fast(a: Foo, b: Foo) -> Foo {
+    intrinsics::fadd_fast(a, b)
+    //~^ ERROR `fadd_fast` intrinsic: expected basic float type, found `Foo`
+}
+
+#[rustc_no_mir] // FIXME #27840 MIR doesn't provide precise spans for calls.
+unsafe fn test_simd_add(a: Foo, b: Foo) -> Foo {
+    simd_add(a, b)
+    //~^ ERROR `simd_add` intrinsic: expected SIMD input type, found non-SIMD `Foo`
+}
+
+fn main() {}