Simplify implementation of Rust intrinsics by using type parameters in the cache

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -15,6 +15,7 @@
 
 use std::fmt::Debug;
 use std::marker::PhantomData;
+use std::num::NonZero;
 use std::ptr;
 
 use bitflags::bitflags;
@@ -1195,6 +1196,17 @@ unsafe extern "C" {
     // Operations on functions
     pub(crate) fn LLVMSetFunctionCallConv(Fn: &Value, CC: c_uint);
 
+    // Operations about llvm intrinsics
+    pub(crate) fn LLVMLookupIntrinsicID(Name: *const c_char, NameLen: size_t) -> c_uint;
+    pub(crate) fn LLVMIntrinsicIsOverloaded(ID: NonZero<c_uint>) -> Bool;
+    pub(crate) fn LLVMIntrinsicCopyOverloadedName2<'a>(
+        Mod: &'a Module,
+        ID: NonZero<c_uint>,
+        ParamTypes: *const &'a Type,
+        ParamCount: size_t,
+        NameLength: *mut size_t,
+    ) -> *mut c_char;
+
     // Operations on parameters
     pub(crate) fn LLVMIsAArgument(Val: &Value) -> Option<&Value>;
     pub(crate) safe fn LLVMCountParams(Fn: &Value) -> c_uint;