Enable Loop Sink pass for functions that has profile.
Summary: For functions with profile data, we are confident that loop sink will be optimal in sinking code.
Reviewers: davidxl, hfinkel
Subscribers: mehdi_amini, mzolotukhin, llvm-commits
Differential Revision: https://reviews.llvm.org/D26155
llvm-svn: 286325
diff --git a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
index aae0134..c340da4 100644
--- a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -626,10 +626,7 @@
// outer loop. LICM pass can help to promote the runtime check out if the
// checked value is loop invariant.
MPM.add(createLICMPass());
-
- // Get rid of LCSSA nodes.
- MPM.add(createInstructionSimplifierPass());
- }
+ }
// After vectorization and unrolling, assume intrinsics may tell us more
// about pointer alignments.
@@ -650,6 +647,9 @@
if (MergeFunctions)
MPM.add(createMergeFunctionsPass());
+ MPM.add(createLoopSinkPass());
+ // Get rid of LCSSA nodes.
+ MPM.add(createInstructionSimplifierPass());
addExtensionsToPM(EP_OptimizerLast, MPM);
}
diff --git a/llvm/lib/Transforms/Scalar/LoopSink.cpp b/llvm/lib/Transforms/Scalar/LoopSink.cpp
index 85249b8..90309d7 100644
--- a/llvm/lib/Transforms/Scalar/LoopSink.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopSink.cpp
@@ -243,6 +243,11 @@
if (!Preheader)
return false;
+ // Enable LoopSink only when runtime profile is available.
+ // With static profile, the sinking decision may be sub-optimal.
+ if (!Preheader->getParent()->getEntryCount())
+ return false;
+
const BlockFrequency PreheaderFreq = BFI.getBlockFreq(Preheader);
// If there are no basic blocks with lower frequency than the preheader then
// we can avoid the detailed analysis as we will never find profitable sinking