Do not use void pointer for ptr_mask intrinsic

I couldn't find where exactly it's documented, but apperantly pointers to void
type are invalid in llvm - void is only allowed as a return type of functions.

Author: WaffleLapkin

compiler/rustc_codegen_llvm/src/context.rs

@@ -644,7 +644,6 @@ impl<'ll> CodegenCx<'ll, '_> {
 
         let i8p = self.type_i8p();
         let void = self.type_void();
-        let voidp = self.type_ptr_to(void);
         let i1 = self.type_i1();
         let t_i8 = self.type_i8();
         let t_i16 = self.type_i16();
@@ -888,7 +887,7 @@ impl<'ll> CodegenCx<'ll, '_> {
             ifn!("llvm.dbg.value", fn(t_metadata, t_i64, t_metadata) -> void);
         }
 
-        ifn!("llvm.ptrmask", fn(voidp, t_isize) -> voidp);
+        ifn!("llvm.ptrmask", fn(i8p, t_isize) -> i8p);
 
         None
     }

src/test/codegen/intrinsics/mask.rs

@@ -4,8 +4,8 @@
 // CHECK-LABEL: @mask_ptr
 // CHECK-SAME: [[WORD:i[0-9]+]] %mask
 #[no_mangle]
-pub fn mask_ptr(ptr: *const u8, mask: usize) -> *const u8 {
+pub fn mask_ptr(ptr: *const u16, mask: usize) -> *const u16 {
     // CHECK: call
-    // CHECK-SAME: @llvm.ptrmask.p0isVoid.[[WORD]](
+    // CHECK-SAME: @llvm.ptrmask.p0i8.[[WORD]](
     core::intrinsics::ptr_mask(ptr, mask)
 }