Use LLVMIntrinsicGetDeclaration to completely remove the hardcoded intrinsics list

compiler/rustc_codegen_llvm/src/llvm/mod.rs

@@ -2,9 +2,9 @@
 
 use std::ffi::{CStr, CString};
 use std::num::NonZero;
+use std::ptr;
 use std::str::FromStr;
 use std::string::FromUtf8Error;
-use std::{ptr, slice};
 
 use libc::c_uint;
 use rustc_abi::{Align, Size, WrappingRange};
@@ -339,34 +339,14 @@ impl Intrinsic {
         NonZero::new(id).map(|id| Self { id })
     }
 
-    pub(crate) fn is_overloaded(self) -> bool {
-        unsafe { LLVMIntrinsicIsOverloaded(self.id) == True }
-    }
-
-    pub(crate) fn overloaded_name<'ll>(
+    pub(crate) fn get_declaration<'ll>(
         self,
         llmod: &'ll Module,
         type_params: &[&'ll Type],
-    ) -> String {
-        let mut len = 0;
-        let ptr = unsafe {
-            LLVMIntrinsicCopyOverloadedName2(
-                llmod,
-                self.id,
-                type_params.as_ptr(),
-                type_params.len(),
-                &mut len,
-            )
-        };
-
-        let slice = unsafe { slice::from_raw_parts_mut(ptr.cast(), len) };
-        let copied = str::from_utf8(slice).expect("Non-UTF8 intrinsic name").to_string();
-
+    ) -> &'ll Value {
         unsafe {
-            libc::free(ptr.cast());
+            LLVMGetIntrinsicDeclaration(llmod, self.id, type_params.as_ptr(), type_params.len())
         }
-
-        copied
     }
 }