remove is_rust_llvm check, since fixes are in final llvm 14 release

Author: erikdesjardins

compiler/rustc_codegen_llvm/src/builder.rs

@@ -1195,9 +1195,9 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         // Cleanup is always the cold path.
         attrs.push(llvm::AttributeKind::Cold.create_attr(self.llcx));
 
-        // In LLVM versions with deferred inlining (currently, system LLVM < 14),
+        // LLVM 14 contains fixes for catastrophic inlining behavior, without which
         // inlining drop glue can lead to exponential size blowup, see #41696 and #92110.
-        if !llvm_util::is_rust_llvm() && llvm_util::get_version() < (14, 0, 0) {
+        if llvm_util::get_version() < (14, 0, 0) {
             attrs.push(llvm::AttributeKind::NoInline.create_attr(self.llcx));
         }
 

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -1929,8 +1929,6 @@ extern "C" {
     pub fn LLVMRustVersionMinor() -> u32;
     pub fn LLVMRustVersionPatch() -> u32;
 
-    pub fn LLVMRustIsRustLLVM() -> bool;
-
     /// Add LLVM module flags.
     ///
     /// In order for Rust-C LTO to work, module flags must be compatible with Clang. What

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -261,12 +261,6 @@ pub fn get_version() -> (u32, u32, u32) {
     }
 }
 
-/// Returns `true` if this LLVM is Rust's bundled LLVM (and not system LLVM).
-pub fn is_rust_llvm() -> bool {
-    // Can be called without initializing LLVM
-    unsafe { llvm::LLVMRustIsRustLLVM() }
-}
-
 pub fn print_passes() {
     // Can be called without initializing LLVM
     unsafe {

compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp

@@ -663,14 +663,6 @@ extern "C" uint32_t LLVMRustVersionMinor() { return LLVM_VERSION_MINOR; }
 
 extern "C" uint32_t LLVMRustVersionMajor() { return LLVM_VERSION_MAJOR; }
 
-extern "C" bool LLVMRustIsRustLLVM() {
-#ifdef LLVM_RUSTLLVM
-  return true;
-#else
-  return false;
-#endif
-}
-
 extern "C" void LLVMRustAddModuleFlag(
     LLVMModuleRef M,
     Module::ModFlagBehavior MergeBehavior,