[PGO][PGSO] Instrument the code gen / target passes.

Summary:
Split off of D67120.

Add the profile guided size optimization instrumentation / queries in the code
gen or target passes. This doesn't enable the size optimizations in those passes
yet as they are currently disabled in shouldOptimizeForSize (for non-IR pass
queries).

A second try after reverted D71072.

Reviewers: davidxl

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71149

1 files changed, 20 insertions, 7 deletions

diff --git a/llvm/lib/CodeGen/BranchFolding.cpp b/llvm/lib/CodeGen/BranchFolding.cpp
index fbf87a52e53..2bf1b392528 100644
--- a/llvm/lib/CodeGen/BranchFolding.cpp
+++ b/llvm/lib/CodeGen/BranchFolding.cpp
@@ -24,6 +24,7 @@
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/ProfileSummaryInfo.h"
 #include "llvm/CodeGen/Analysis.h"
 #include "llvm/CodeGen/LivePhysRegs.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"
@@ -38,6 +39,7 @@
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineOperand.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/MachineSizeOpts.h"
 #include "llvm/CodeGen/TargetInstrInfo.h"
 #include "llvm/CodeGen/TargetOpcodes.h"
 #include "llvm/CodeGen/TargetPassConfig.h"
@@ -103,6 +105,7 @@ namespace {
     void getAnalysisUsage(AnalysisUsage &AU) const override {
       AU.addRequired<MachineBlockFrequencyInfo>();
       AU.addRequired<MachineBranchProbabilityInfo>();
+      AU.addRequired<ProfileSummaryInfoWrapperPass>();
       AU.addRequired<TargetPassConfig>();
       MachineFunctionPass::getAnalysisUsage(AU);
     }
@@ -129,7 +132,8 @@ bool BranchFolderPass::runOnMachineFunction(MachineFunction &MF) {
   BranchFolder::MBFIWrapper MBBFreqInfo(
       getAnalysis<MachineBlockFrequencyInfo>());
   BranchFolder Folder(EnableTailMerge, /*CommonHoist=*/true, MBBFreqInfo,
-                      getAnalysis<MachineBranchProbabilityInfo>());
+                      getAnalysis<MachineBranchProbabilityInfo>(),
+                      &getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI());
   auto *MMIWP = getAnalysisIfAvailable<MachineModuleInfoWrapperPass>();
   return Folder.OptimizeFunction(
       MF, MF.getSubtarget().getInstrInfo(), MF.getSubtarget().getRegisterInfo(),
@@ -139,9 +143,10 @@ bool BranchFolderPass::runOnMachineFunction(MachineFunction &MF) {
 BranchFolder::BranchFolder(bool defaultEnableTailMerge, bool CommonHoist,
                            MBFIWrapper &FreqInfo,
                            const MachineBranchProbabilityInfo &ProbInfo,
+                           ProfileSummaryInfo *PSI,
                            unsigned MinTailLength)
     : EnableHoistCommonCode(CommonHoist), MinCommonTailLength(MinTailLength),
-      MBBFreqInfo(FreqInfo), MBPI(ProbInfo) {
+      MBBFreqInfo(FreqInfo), MBPI(ProbInfo), PSI(PSI) {
   if (MinCommonTailLength == 0)
     MinCommonTailLength = TailMergeSize;
   switch (FlagEnableTailMerge) {
@@ -585,7 +590,9 @@ ProfitableToMerge(MachineBasicBlock *MBB1, MachineBasicBlock *MBB2,
                   MachineBasicBlock::iterator &I2, MachineBasicBlock *SuccBB,
                   MachineBasicBlock *PredBB,
                   DenseMap<const MachineBasicBlock *, int> &EHScopeMembership,
-                  bool AfterPlacement) {
+                  bool AfterPlacement,
+                  BranchFolder::MBFIWrapper &MBBFreqInfo,
+                  ProfileSummaryInfo *PSI) {
   // It is never profitable to tail-merge blocks from two different EH scopes.
   if (!EHScopeMembership.empty()) {
     auto EHScope1 = EHScopeMembership.find(MBB1);
@@ -682,7 +689,11 @@ ProfitableToMerge(MachineBasicBlock *MBB1, MachineBasicBlock *MBB2,
   // branch instruction, which is likely to be smaller than the 2
   // instructions that would be deleted in the merge.
   MachineFunction *MF = MBB1->getParent();
-  return EffectiveTailLen >= 2 && MF->getFunction().hasOptSize() &&
+  bool OptForSize =
+      MF->getFunction().hasOptSize() ||
+      (llvm::shouldOptimizeForSize(MBB1, PSI, &MBBFreqInfo.getMBFI()) &&
+       llvm::shouldOptimizeForSize(MBB2, PSI, &MBBFreqInfo.getMBFI()));
+  return EffectiveTailLen >= 2 && OptForSize &&
          (FullBlockTail1 || FullBlockTail2);
 }
 
@@ -704,7 +715,7 @@ unsigned BranchFolder::ComputeSameTails(unsigned CurHash,
                             CommonTailLen, TrialBBI1, TrialBBI2,
                             SuccBB, PredBB,
                             EHScopeMembership,
-                            AfterBlockPlacement)) {
+                            AfterBlockPlacement, MBBFreqInfo, PSI)) {
         if (CommonTailLen > maxCommonTailLength) {
           SameTails.clear();
           maxCommonTailLength = CommonTailLen;
@@ -1534,8 +1545,10 @@ ReoptimizeBlock:
     }
   }
 
-  if (!IsEmptyBlock(MBB) && MBB->pred_size() == 1 &&
-      MF.getFunction().hasOptSize()) {
+  bool OptForSize =
+      MF.getFunction().hasOptSize() ||
+      llvm::shouldOptimizeForSize(MBB, PSI, &MBBFreqInfo.getMBFI());
+  if (!IsEmptyBlock(MBB) && MBB->pred_size() == 1 && OptForSize) {
     // Changing "Jcc foo; foo: jmp bar;" into "Jcc bar;" might change the branch
     // direction, thereby defeating careful block placement and regressing
     // performance. Therefore, only consider this for optsize functions.