[PATCH] D91019: [NewPM] Bail from PassManager::run() if there are no passes

[Arthur Eubanks via Phabricator via llvm-commits]

aeubanks created this revision.
aeubanks added reviewers: MaskRay, ychen, asbirlea.
Herald added a reviewer: bollu.
Herald added subscribers: llvm-commits, dexonsmith.
Herald added a project: LLVM.
aeubanks requested review of this revision.

With D89158 <https://reviews.llvm.org/D89158>, we have the possibility of creating empty pass managers due
to callbacks choosing to not add passes under -O0.  e.g. Polly can add
EP callbacks but not add any passes. This affects some tests that use
-debug-pass-manager, like the one fixed in 8eb338a92a4e <https://reviews.llvm.org/rG8eb338a92a4ea300bc3cbdd423500ca8b24f2094>.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D91019

Files:
  llvm/include/llvm/IR/PassManager.h
  llvm/test/Other/new-pass-manager.ll


Index: llvm/test/Other/new-pass-manager.ll
===================================================================
--- llvm/test/Other/new-pass-manager.ll
+++ llvm/test/Other/new-pass-manager.ll
@@ -356,17 +356,11 @@
 ; CHECK-CALLGRAPH: Running analysis: CallGraphAnalysis
 ; CHECK-CALLGRAPH: Finished llvm::Module pass manager run
 
-;; If Polly is enabled, registerPollyPasses adds an ep-vectorizer-start callback.
-;; There may or may not be a function pass manager run.
-;; Add a no-op-function to unify the two cases.
 ; RUN: opt -disable-output -disable-verify -debug-pass-manager \
-; RUN:     -passes='default<O0>' -passes-ep-vectorizer-start=no-op-function %s 2>&1 \
+; RUN:     -passes='default<O0>' %s 2>&1 \
 ; RUN:     | FileCheck %s --check-prefix=CHECK-O0
 ; CHECK-O0: Starting llvm::Module pass manager run
 ; CHECK-O0-NEXT: Running analysis: InnerAnalysisManagerProxy<{{.*}}>
-; CHECK-O0-NEXT: Starting llvm::Function pass manager run
-; CHECK-O0-NEXT: Running pass: NoOpFunctionPass on foo
-; CHECK-O0-NEXT: Finished llvm::Function pass manager run
 ; CHECK-O0-NEXT: Finished llvm::Module pass manager run
 
 ; RUN: opt -disable-output -disable-verify -debug-pass-manager \
Index: llvm/include/llvm/IR/PassManager.h
===================================================================
--- llvm/include/llvm/IR/PassManager.h
+++ llvm/include/llvm/IR/PassManager.h
@@ -491,6 +491,9 @@
                         ExtraArgTs... ExtraArgs) {
     PreservedAnalyses PA = PreservedAnalyses::all();
 
+    if (Passes.empty())
+      return PA;
+
     // Request PassInstrumentation from analysis manager, will use it to run
     // instrumenting callbacks for the passes later.
     // Here we use std::tuple wrapper over getResult which helps to extract


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