From b6da9cf3b765506fce0a954c29164ca56f85377c Mon Sep 17 00:00:00 2001 From: Michael Kuperstein Date: Thu, 29 Dec 2016 22:37:13 +0000 Subject: [LICM] Only recompute LCSSA when we actually promoted something. We want to recompute LCSSA only when we actually promoted a value. This means we only need to look at changes made by promotion when deciding whether to recompute it or not, not at regular sinking/hoisting. (This was what the code was documented as doing, just not what it did) Hopefully NFC. llvm-svn: 290726 --- llvm/lib/Transforms/Scalar/LICM.cpp | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'llvm/lib') diff --git a/llvm/lib/Transforms/Scalar/LICM.cpp b/llvm/lib/Transforms/Scalar/LICM.cpp index c981a8ff96b..30a70379968 100644 --- a/llvm/lib/Transforms/Scalar/LICM.cpp +++ b/llvm/lib/Transforms/Scalar/LICM.cpp @@ -255,9 +255,11 @@ bool LoopInvariantCodeMotion::runOnLoop(Loop *L, AliasAnalysis *AA, SmallVector InsertPts; PredIteratorCache PIC; + bool Promoted = false; + // Loop over all of the alias sets in the tracker object. for (AliasSet &AS : *CurAST) - Changed |= promoteLoopAccessesToScalars( + Promoted |= promoteLoopAccessesToScalars( AS, ExitBlocks, InsertPts, PIC, LI, DT, TLI, L, CurAST, &SafetyInfo); // Once we have promoted values across the loop body we have to recursively @@ -266,9 +268,10 @@ bool LoopInvariantCodeMotion::runOnLoop(Loop *L, AliasAnalysis *AA, // FIXME: This is really heavy handed. It would be a bit better to use an // SSAUpdater strategy during promotion that was LCSSA aware and reformed // it as it went. - if (Changed) { + if (Promoted) formLCSSARecursively(*L, *DT, LI, SE); - } + + Changed |= Promoted; } // Check that neither this loop nor its parent have had LCSSA broken. LICM is -- cgit v1.2.3