[PGO][PGSO] Temporarily disable the large working set size behavior.

Summary:
This temporarily disables the large working set size behavior in profile guided
size optimization due to internal benchmark regressions.

Reviewers: davidxl

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70207

Author: hjyamauchi

llvm/include/llvm/Transforms/Utils/SizeOpts.h

@@ -21,6 +21,7 @@ using namespace llvm;
 
 extern cl::opt<bool> EnablePGSO;
 extern cl::opt<bool> PGSOLargeWorkingSetSizeOnly;
+extern cl::opt<bool> PGSOColdCodeOnly;
 extern cl::opt<bool> ForcePGSO;
 extern cl::opt<int> PgsoCutoffInstrProf;
 extern cl::opt<int> PgsoCutoffSampleProf;
@@ -42,7 +43,8 @@ bool shouldFuncOptimizeForSizeImpl(const FuncT *F, ProfileSummaryInfo *PSI,
     return true;
   if (!EnablePGSO)
     return false;
-  if (PGSOLargeWorkingSetSizeOnly && !PSI->hasLargeWorkingSetSize()) {
+  if (PGSOColdCodeOnly ||
+      (PGSOLargeWorkingSetSizeOnly && !PSI->hasLargeWorkingSetSize())) {
     // Even if the working set size isn't large, size-optimize cold code.
     return AdapterT::isFunctionColdInCallGraph(F, PSI, *BFI);
   }
@@ -61,7 +63,8 @@ bool shouldOptimizeForSizeImpl(const BlockT *BB, ProfileSummaryInfo *PSI,
     return true;
   if (!EnablePGSO)
     return false;
-  if (PGSOLargeWorkingSetSizeOnly && !PSI->hasLargeWorkingSetSize()) {
+  if (PGSOColdCodeOnly ||
+      (PGSOLargeWorkingSetSizeOnly && !PSI->hasLargeWorkingSetSize())) {
     // Even if the working set size isn't large, size-optimize cold code.
     return AdapterT::isColdBlock(BB, PSI, BFI);
   }

llvm/lib/Transforms/Utils/SizeOpts.cpp

@@ -23,6 +23,11 @@ cl::opt<bool> PGSOLargeWorkingSetSizeOnly(
     cl::desc("Apply the profile guided size optimizations only "
              "if the working set size is large (except for cold code.)"));
 
+cl::opt<bool> PGSOColdCodeOnly(
+    "pgso-cold-code-only", cl::Hidden, cl::init(true),
+    cl::desc("Apply the profile guided size optimizations only "
+             "to cold code."));
+
 cl::opt<bool> ForcePGSO(
     "force-pgso", cl::Hidden, cl::init(false),
     cl::desc("Force the (profiled-guided) size optimizations. "));