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base repository: rust-lang/llvm
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head repository: rust-lang/llvm
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compare: c7a16bd57c2a9c643a52f0cebecdaf0b6a996da1
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  • 2 commits
  • 2 files changed
  • 1 contributor

Commits on Oct 5, 2017

  1. [PassManager] Run global optimizations after the inliner. 

    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.

This fixes PR34652.

Differential Revision: https://reviews.llvm.org/D38154

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314997 91177308-0d34-0410-b5e6-96231b3b80d8
    @dcci @alexcrichton
    dcci authored and alexcrichton committed Oct 5, 2017
    Copy the full SHA
    1aecec4 View commit details

  2. [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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314999 91177308-0d34-0410-b5e6-96231b3b80d8
    @dcci @alexcrichton
    dcci authored and alexcrichton committed Oct 5, 2017
    Copy the full SHA
    c7a16bd View commit details
Showing with 16 additions and 3 deletions.
  1. +13 −2 lib/Transforms/IPO/PassManagerBuilder.cpp
  2. +3 −1 test/Other/pass-pipelines.ll
15 changes: 13 additions & 2 deletions lib/Transforms/IPO/PassManagerBuilder.cpp
View file
Original file line number Diff line number Diff line change
@@ -475,9 +475,11 @@ void PassManagerBuilder::populateModulePassManager(
// Start of CallGraph SCC passes.
if (!DisableUnitAtATime)
MPM.add(createPruneEHPass()); // Remove dead EH info
bool RunInliner = false;
if (Inliner) {
MPM.add(Inliner);
Inliner = nullptr;
RunInliner = true;
}
if (!DisableUnitAtATime)
MPM.add(createPostOrderFunctionAttrsLegacyPass());
@@ -508,12 +510,21 @@ void PassManagerBuilder::populateModulePassManager(
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;
4 changes: 3 additions & 1 deletion test/Other/pass-pipelines.ll
View file
Original file line number Diff line number Diff line change
@@ -55,13 +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: 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