This is an archive of the discontinued LLVM Phabricator instance.

Differential D28117

[NewGVN] Merge unconditional branches before value numbering
ClosedPublic

Authored by davide on Dec 26 2016, 6:09 AM.

Details

Reviewers
• dberlin
Commits
rG8ea5e4fcae0f: [NewGVN] Change test to reflect difference between GVN and NewGVN.
rL290546: [NewGVN] Change test to reflect difference between GVN and NewGVN.
Summary

We're discussing it in https://llvm.org/bugs/show_bug.cgi?id=31468
Patch on phab for easier reviews.

Diff Detail

Event Timeline

davide updated this revision to Diff 82498.Dec 26 2016, 6:09 AM
davide retitled this revision from to [NewGVN] Merge conditional branches before value numbering.
davide updated this object.
davide added a reviewer: • dberlin.
davide retitled this revision from [NewGVN] Merge conditional branches before value numbering to [NewGVN] Merge unconditional branches before value numbering.
davide added a subscriber: llvm-commits.
davide updated this revision to Diff 82505.Dec 26 2016, 7:32 AM

fix a typo

davide updated this revision to Diff 82506.Dec 26 2016, 7:32 AM
davide updated this revision to Diff 82507.

fix a typo

Closed by commit rL290546: [NewGVN] Change test to reflect difference between GVN and NewGVN. (authored by davide). · Explain WhyDec 26 2016, 10:20 AM
This revision was automatically updated to reflect the committed changes.

Revision Contents

PathSize
lib/
Transforms/
Scalar/
14 lines
test/
Transforms/
NewGVN/
1 line

Diff 82506

lib/Transforms/Scalar/NewGVN.cpp

Context not available.
unsigned ICount = 0; unsigned ICount = 0;
SmallPtrSet<BasicBlock *, 16> VisitedBlocks; SmallPtrSet<BasicBlock *, 16> VisitedBlocks;
// Do a sweep over all the basic blocks to merge unconditional branches.
for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE;) {
BasicBlock *BB = &*FI++;
// In theory here we could pass MemSSA if/when MergeBlockIntoPredecessor
// will grow version which accepts the analysis.
bool removedBlock = MergeBlockIntoPredecessor(
BB, DT, nullptr /* LoopInfo */, nullptr /* MemDep */);
if (removedBlock)
NumGVNBlocksDeleted++;
Changed |= removedBlock;
}
// Note: We want RPO traversal of the blocks, which is not quite the same as // Note: We want RPO traversal of the blocks, which is not quite the same as
// dominator tree order, particularly with regard whether backedges get // dominator tree order, particularly with regard whether backedges get
// visited first or second, given a block with multiple successors. // visited first or second, given a block with multiple successors.
Context not available.

test/Transforms/NewGVN/basic.ll

; XFAIL: *
; RUN: opt < %s -newgvn -S | FileCheck %s ; RUN: opt < %s -newgvn -S | FileCheck %s
define i32 @main() { define i32 @main() {