Default to disabling the new pass manager for the s390x targets.

Author: hkratz

compiler/rustc_codegen_llvm/src/back/lto.rs

@@ -596,7 +596,7 @@ pub(crate) fn run_pass_manager(
     //      tools/lto/LTOCodeGenerator.cpp
     debug!("running the pass manager");
     unsafe {
-        if write::should_use_new_llvm_pass_manager(config) {
+        if write::should_use_new_llvm_pass_manager(cgcx, config) {
             let opt_stage = if thin { llvm::OptStage::ThinLTO } else { llvm::OptStage::FatLTO };
             let opt_level = config.opt_level.unwrap_or(config::OptLevel::No);
             write::optimize_with_new_llvm_pass_manager(

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -377,10 +377,19 @@ fn get_pgo_sample_use_path(config: &ModuleConfig) -> Option<CString> {
         .map(|path_buf| CString::new(path_buf.to_string_lossy().as_bytes()).unwrap())
 }
 
-pub(crate) fn should_use_new_llvm_pass_manager(config: &ModuleConfig) -> bool {
+pub(crate) fn should_use_new_llvm_pass_manager(
+    cgcx: &CodegenContext<LlvmCodegenBackend>,
+    config: &ModuleConfig,
+) -> bool {
     // The new pass manager is enabled by default for LLVM >= 13.
     // This matches Clang, which also enables it since Clang 13.
-    config.new_llvm_pass_manager.unwrap_or_else(|| llvm_util::get_version() >= (13, 0, 0))
+
+    // FIXME: There are some perf issues with the new pass manager
+    // when targeting s390x, so it is temporarily disabled for that
+    // arch, see https://github.com/rust-lang/rust/issues/89609
+    config
+        .new_llvm_pass_manager
+        .unwrap_or_else(|| cgcx.target_arch != "s390x" && llvm_util::get_version() >= (13, 0, 0))
 }
 
 pub(crate) unsafe fn optimize_with_new_llvm_pass_manager(
@@ -482,7 +491,7 @@ pub(crate) unsafe fn optimize(
     }
 
     if let Some(opt_level) = config.opt_level {
-        if should_use_new_llvm_pass_manager(config) {
+        if should_use_new_llvm_pass_manager(cgcx, config) {
             let opt_stage = match cgcx.lto {
                 Lto::Fat => llvm::OptStage::PreLinkFatLTO,
                 Lto::Thin | Lto::ThinLocal => llvm::OptStage::PreLinkThinLTO,