[LTO] Remove Config.UseDefaultPipeline

[igorkudrin]

This option is not used. It was added in D122133, 5856f30, with the only usage in ClangLinkerWrapper.cpp, which was later updated in a1d57fc, and then finally removed in D142650, 6185246.

[llvmbot]

@llvm/pr-subscribers-lto

Author: Igor Kudrin (igorkudrin)

Changes

This option is not used. It was added in D122133, 5856f30, with the only usage in ClangLinkerWrapper.cpp, which was later updated in a1d57fc, and then finally removed in D142650, 6185246.

---

Full diff: https://github.com/llvm/llvm-project/pull/82587.diff

2 Files Affected:

• (modified) llvm/include/llvm/LTO/Config.h (-3)
• (modified) llvm/lib/LTO/LTOBackend.cpp (-2)

diff --git a/llvm/include/llvm/LTO/Config.h b/llvm/include/llvm/LTO/Config.h
index 6fb55f1cf1686a..482b6e55a19d35 100644
--- a/llvm/include/llvm/LTO/Config.h
+++ b/llvm/include/llvm/LTO/Config.h
@@ -60,9 +60,6 @@ struct Config {
   bool VerifyEach = false;
   bool DisableVerify = false;
 
-  /// Use the standard optimization pipeline.
-  bool UseDefaultPipeline = false;
-
   /// Flag to indicate that the optimizer should not assume builtins are present
   /// on the target.
   bool Freestanding = false;
diff --git a/llvm/lib/LTO/LTOBackend.cpp b/llvm/lib/LTO/LTOBackend.cpp
index 7b3a7590dfa743..6cfe67779b1a7d 100644
--- a/llvm/lib/LTO/LTOBackend.cpp
+++ b/llvm/lib/LTO/LTOBackend.cpp
@@ -330,8 +330,6 @@ static void runNewPMPasses(const Config &Conf, Module &Mod, TargetMachine *TM,
       report_fatal_error(Twine("unable to parse pass pipeline description '") +
                          Conf.OptPipeline + "': " + toString(std::move(Err)));
     }
-  } else if (Conf.UseDefaultPipeline) {
-    MPM.addPass(PB.buildPerModuleDefaultPipeline(OL));
   } else if (IsThinLTO) {
     MPM.addPass(PB.buildThinLTODefaultPipeline(OL, ImportSummary));
   } else {

[jhuber6]

Yeah this was to fix a large performance regression in some application on the short term but has since been fixed correctly. Thanks for catching this.