[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).

Reviewers: davidxl

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71072

1 files changed, 22 insertions, 4 deletions

diff --git a/llvm/lib/CodeGen/MachineBlockPlacement.cpp b/llvm/lib/CodeGen/MachineBlockPlacement.cpp
index c2d9d1b9ac7..30b98ec88c2 100644
--- a/llvm/lib/CodeGen/MachineBlockPlacement.cpp
+++ b/llvm/lib/CodeGen/MachineBlockPlacement.cpp
@@ -33,6 +33,7 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/BlockFrequencyInfoImpl.h"
+#include "llvm/Analysis/ProfileSummaryInfo.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"
 #include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
 #include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
@@ -41,6 +42,7 @@
 #include "llvm/CodeGen/MachineLoopInfo.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachinePostDominators.h"
+#include "llvm/CodeGen/MachineSizeOpts.h"
 #include "llvm/CodeGen/TailDuplicator.h"
 #include "llvm/CodeGen/TargetInstrInfo.h"
 #include "llvm/CodeGen/TargetLowering.h"
@@ -363,6 +365,8 @@ class MachineBlockPlacement : public MachineFunctionPass {
   /// A handle to the post dominator tree.
   MachinePostDominatorTree *MPDT;
 
+  ProfileSummaryInfo *PSI;
+
   /// Duplicator used to duplicate tails during placement.
   ///
   /// Placement decisions can open up new tail duplication opportunities, but
@@ -538,6 +542,7 @@ public:
     if (TailDupPlacement)
       AU.addRequired<MachinePostDominatorTree>();
     AU.addRequired<MachineLoopInfo>();
+    AU.addRequired<ProfileSummaryInfoWrapperPass>();
     AU.addRequired<TargetPassConfig>();
     MachineFunctionPass::getAnalysisUsage(AU);
   }
@@ -555,6 +560,7 @@ INITIALIZE_PASS_DEPENDENCY(MachineBranchProbabilityInfo)
 INITIALIZE_PASS_DEPENDENCY(MachineBlockFrequencyInfo)
 INITIALIZE_PASS_DEPENDENCY(MachinePostDominatorTree)
 INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
+INITIALIZE_PASS_DEPENDENCY(ProfileSummaryInfoWrapperPass)
 INITIALIZE_PASS_END(MachineBlockPlacement, DEBUG_TYPE,
                     "Branch Probability Basic Block Placement", false, false)
 
@@ -2075,7 +2081,10 @@ MachineBlockPlacement::findBestLoopTop(const MachineLoop &L,
   // i.e. when the layout predecessor does not fallthrough to the loop header.
   // In practice this never happens though: there always seems to be a preheader
   // that can fallthrough and that is also placed before the header.
-  if (F->getFunction().hasOptSize())
+  bool OptForSize = F->getFunction().hasOptSize() ||
+                    llvm::shouldOptimizeForSize(L.getHeader(), PSI,
+                                                &MBFI->getMBFI());
+  if (OptForSize)
     return L.getHeader();
 
   MachineBasicBlock *OldTop = nullptr;
@@ -2831,6 +2840,11 @@ void MachineBlockPlacement::alignBlocks() {
     if (Freq < (LoopHeaderFreq * ColdProb))
       continue;
 
+    // If the global profiles indicates so, don't align it.
+    if (llvm::shouldOptimizeForSize(ChainBB, PSI, &MBFI->getMBFI()) &&
+        !TLI->alignLoopsWithOptSize())
+      continue;
+
     // Check for the existence of a non-layout predecessor which would benefit
     // from aligning this block.
     MachineBasicBlock *LayoutPred =
@@ -3038,6 +3052,7 @@ bool MachineBlockPlacement::runOnMachineFunction(MachineFunction &MF) {
   TII = MF.getSubtarget().getInstrInfo();
   TLI = MF.getSubtarget().getTargetLowering();
   MPDT = nullptr;
+  PSI = &getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI();
 
   // Initialize PreferredLoopExit to nullptr here since it may never be set if
   // there are no MachineLoops.
@@ -3068,10 +3083,13 @@ bool MachineBlockPlacement::runOnMachineFunction(MachineFunction &MF) {
 
   if (allowTailDupPlacement()) {
     MPDT = &getAnalysis<MachinePostDominatorTree>();
-    if (MF.getFunction().hasOptSize())
+    bool OptForSize = MF.getFunction().hasOptSize() ||
+                      llvm::shouldOptimizeForSize(&MF, PSI, &MBFI->getMBFI());
+    if (OptForSize)
       TailDupSize = 1;
     bool PreRegAlloc = false;
-    TailDup.initMF(MF, PreRegAlloc, MBPI, /* LayoutMode */ true, TailDupSize);
+    TailDup.initMF(MF, PreRegAlloc, MBPI, &MBFI->getMBFI(), PSI,
+                   /* LayoutMode */ true, TailDupSize);
     precomputeTriangleChains();
   }
 
@@ -3087,7 +3105,7 @@ bool MachineBlockPlacement::runOnMachineFunction(MachineFunction &MF) {
   if (MF.size() > 3 && EnableTailMerge) {
     unsigned TailMergeSize = TailDupSize + 1;
     BranchFolder BF(/*EnableTailMerge=*/true, /*CommonHoist=*/false, *MBFI,
-                    *MBPI, TailMergeSize);
+                    *MBPI, PSI, TailMergeSize);
 
     auto *MMIWP = getAnalysisIfAvailable<MachineModuleInfoWrapperPass>();
     if (BF.OptimizeFunction(MF, TII, MF.getSubtarget().getRegisterInfo(),