[llvm] r314999 - [PassManager] Improve the interaction between -O2 and ThinLTO.
Davide Italiano via llvm-commits
llvm-commits at lists.llvm.org
Thu Oct 5 11:23:25 PDT 2017
Author: davide
Date: Thu Oct 5 11:23:25 2017
New Revision: 314999
URL: http://llvm.org/viewvc/llvm-project?rev=314999&view=rev
Log:
[PassManager] Improve the interaction between -O2 and ThinLTO.
Run GDCE slightly later so that we don't have to repeat it
twice when preparing for Thin. Thanks to Mehdi for the suggestion.
Modified:
llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp
llvm/trunk/test/Other/pass-pipelines.ll
Modified: llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp?rev=314999&r1=314998&r2=314999&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp Thu Oct 5 11:23:25 2017
@@ -508,17 +508,6 @@ void PassManagerBuilder::populateModuleP
// we must insert a no-op module pass to reset the pass manager.
MPM.add(createBarrierNoopPass());
- // The inliner performs some kind of dead code elimination as it goes,
- // but there are cases that are not really caught by it. We might
- // at some point consider teaching the inliner about them, but it
- // is OK for now to run GlobalOpt + GlobalDCE in tandem as their
- // benefits generally outweight the cost, making the whole pipeline
- // faster.
- if (RunInliner) {
- MPM.add(createGlobalOptimizerPass());
- MPM.add(createGlobalDCEPass());
- }
-
if (RunPartialInlining)
MPM.add(createPartialInliningPass());
@@ -538,12 +527,21 @@ void PassManagerBuilder::populateModuleP
if (!DisableUnitAtATime)
MPM.add(createReversePostOrderFunctionAttrsPass());
+ // The inliner performs some kind of dead code elimination as it goes,
+ // but there are cases that are not really caught by it. We might
+ // at some point consider teaching the inliner about them, but it
+ // is OK for now to run GlobalOpt + GlobalDCE in tandem as their
+ // benefits generally outweight the cost, making the whole pipeline
+ // faster.
+ if (RunInliner) {
+ MPM.add(createGlobalOptimizerPass());
+ MPM.add(createGlobalDCEPass());
+ }
+
// If we are planning to perform ThinLTO later, let's not bloat the code with
// unrolling/vectorization/... now. We'll first run the inliner + CGSCC passes
// during ThinLTO and perform the rest of the optimizations afterward.
if (PrepareForThinLTO) {
- // Reduce the size of the IR as much as possible.
- MPM.add(createGlobalOptimizerPass());
// Rename anon globals to be able to export them in the summary.
MPM.add(createNameAnonGlobalPass());
return;
Modified: llvm/trunk/test/Other/pass-pipelines.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Other/pass-pipelines.ll?rev=314999&r1=314998&r2=314999&view=diff
==============================================================================
--- llvm/trunk/test/Other/pass-pipelines.ll (original)
+++ llvm/trunk/test/Other/pass-pipelines.ll Thu Oct 5 11:23:25 2017
@@ -55,15 +55,15 @@
; Next we break out of the main Function passes inside the CGSCC pipeline with
; a barrier pass.
; CHECK-O2: A No-Op Barrier Pass
-; Reduce the size of the IR ASAP after the inliner.
-; CHECK-O2-NEXT: Global Variable Optimizer
-; CHECK-O2: Dead Global Elimination
; CHECK-O2-NEXT: Eliminate Available Externally
; Inferring function attribute should be right after the CGSCC pipeline, before
; any other optimizations/analyses.
; CHECK-O2-NEXT: CallGraph
; CHECK-O2-NEXT: Deduce function attributes in RPO
; CHECK-O2-NOT: Manager
+; Reduce the size of the IR ASAP after the inliner.
+; CHECK-O2-NEXT: Global Variable Optimizer
+; CHECK-O2: Dead Global Elimination
; Next is the late function pass pipeline.
; CHECK-O2: FunctionPass Manager
; CHECK-O2-NOT: Manager
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