This is an archive of the discontinued LLVM Phabricator instance.

Differential D18626

[PM] Add a SpeculativeExecution pass for targets with divergent branches.
ClosedPublic

Authored by jlebar on Mar 30 2016, 2:46 PM.

Details

Reviewers
chandlerc
Commits
rGcf63b64fc645: [PM] Add a SpeculativeExecution pass for targets with divergent branches.
rL266399: [PM] Add a SpeculativeExecution pass for targets with divergent branches.
Summary

This IR pass is helpful for GPUs, and other targets with divergent
branches. It's a nop on targets without divergent branches.

Diff Detail

Repository
rL LLVM

Event Timeline

jlebar updated this revision to Diff 52131.Mar 30 2016, 2:46 PM
jlebar retitled this revision from to [PM] Add a SpeculativeExecution pass for targets with divergent branches..
jlebar updated this object.
jlebar added a reviewer: chandlerc.
jlebar added subscribers: tra, rnk, jingyue, llvm-commits.
Herald added a subscriber: mehdi_amini. · View Herald TranscriptMar 30 2016, 2:46 PM
mehdi_amini added inline comments.Mar 30 2016, 3:31 PM
lib/Transforms/IPO/PassManagerBuilder.cpp
238 ↗(On Diff #52131)

Where is it defined? I can't find in my tree.

mehdi_amini added a parent revision: D18625: [Speculation] Add a SpeculativeExecution mode where the pass does nothing unless TTI::hasBranchDivergence() is true..Mar 30 2016, 3:32 PM
mehdi_amini added inline comments.
lib/Transforms/IPO/PassManagerBuilder.cpp
238 ↗(On Diff #52131)

Found D18625 (added as dependency for this patch)

tra added inline comments.Mar 30 2016, 3:32 PM
lib/Transforms/IPO/PassManagerBuilder.cpp
238 ↗(On Diff #52131)

http://reviews.llvm.org/D18625

chandlerc accepted this revision.Apr 7 2016, 12:33 AM
chandlerc edited edge metadata.

I've suggested merging this into D18625 but if you decide not to, this LGTM.

This revision is now accepted and ready to land.Apr 7 2016, 12:33 AM
jlebar mentioned this in D18625: [Speculation] Add a SpeculativeExecution mode where the pass does nothing unless TTI::hasBranchDivergence() is true..Apr 12 2016, 9:22 AM
Closed by commit rL266399: [PM] Add a SpeculativeExecution pass for targets with divergent branches. (authored by jlebar). · Explain WhyApr 14 2016, 5:37 PM
This revision was automatically updated to reflect the committed changes.

Revision Contents

PathSize
llvm/
trunk/
lib/
Transforms/
IPO/
2 lines

Diff 53825

llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp

Show First 20 Lines • Show All 228 Lines • ▼ Show 20 Linesvoid PassManagerBuilder::addFunctionSimplificationPasses(
legacy::PassManagerBase &MPM) { legacy::PassManagerBase &MPM) {
// Start of function pass. // Start of function pass.
// Break up aggregate allocas, using SSAUpdater. // Break up aggregate allocas, using SSAUpdater.
if (UseNewSROA) if (UseNewSROA)
MPM.add(createSROAPass()); MPM.add(createSROAPass());
else else
MPM.add(createScalarReplAggregatesPass(-1, false)); MPM.add(createScalarReplAggregatesPass(-1, false));
MPM.add(createEarlyCSEPass()); // Catch trivial redundancies MPM.add(createEarlyCSEPass()); // Catch trivial redundancies
// Speculative execution if the target has divergent branches; otherwise nop.
MPM.add(createSpeculativeExecutionIfHasBranchDivergencePass());
MPM.add(createJumpThreadingPass()); // Thread jumps. MPM.add(createJumpThreadingPass()); // Thread jumps.
MPM.add(createCorrelatedValuePropagationPass()); // Propagate conditionals MPM.add(createCorrelatedValuePropagationPass()); // Propagate conditionals
MPM.add(createCFGSimplificationPass()); // Merge & remove BBs MPM.add(createCFGSimplificationPass()); // Merge & remove BBs
// Combine silly seq's // Combine silly seq's
addInstructionCombiningPass(MPM); addInstructionCombiningPass(MPM);
addExtensionsToPM(EP_Peephole, MPM); addExtensionsToPM(EP_Peephole, MPM);
MPM.add(createTailCallEliminationPass()); // Eliminate tail calls MPM.add(createTailCallEliminationPass()); // Eliminate tail calls
▲ Show 20 Lines • Show All 612 Lines • Show Last 20 Lines