[llvm] InstrProfiling: Split creating Bias offset to getOrCreateBiasVar(Name). NFC. (PR #95692)

[NAKAMURA Takumi via llvm-commits]

https://github.com/chapuni updated https://github.com/llvm/llvm-project/pull/95692

>From 7a46d83c007261a7c1686298b7e46967199cafd2 Mon Sep 17 00:00:00 2001
From: NAKAMURA Takumi <geek4civic at gmail.com>
Date: Sun, 16 Jun 2024 17:15:40 +0900
Subject: [PATCH 1/2] Split creating Bias offset to getOrCreateBiasVar(Name).
 NFC.

---
 .../Instrumentation/InstrProfiling.cpp        | 44 ++++++++++++-------
 1 file changed, 28 insertions(+), 16 deletions(-)

diff --git a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
index 9c34374f0ece1..213044800053f 100644
--- a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
+++ b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
@@ -278,6 +278,10 @@ class InstrLowerer final {
   /// using the index represented by the a temp value into a bitmap.
   void lowerMCDCTestVectorBitmapUpdate(InstrProfMCDCTVBitmapUpdate *Ins);
 
+  /// Get the Bias value for data to access mmap-ed area.
+  /// Create it if it hasn't been seen.
+  GlobalVariable *getOrCreateBiasVar(StringRef VarName);
+
   /// Compute the address of the counter value that this profiling instruction
   /// acts on.
   Value *getCounterAddress(InstrProfCntrInstBase *I);
@@ -885,6 +889,29 @@ void InstrLowerer::lowerValueProfileInst(InstrProfValueProfileInst *Ind) {
   Ind->eraseFromParent();
 }
 
+GlobalVariable *InstrLowerer::getOrCreateBiasVar(StringRef VarName) {
+  auto *Bias = M.getGlobalVariable(VarName);
+  if (Bias)
+    return Bias;
+
+  Type *Int64Ty = Type::getInt64Ty(M.getContext());
+
+  // Compiler must define this variable when runtime counter relocation
+  // is being used. Runtime has a weak external reference that is used
+  // to check whether that's the case or not.
+  Bias = new GlobalVariable(M, Int64Ty, false, GlobalValue::LinkOnceODRLinkage,
+                            Constant::getNullValue(Int64Ty), VarName);
+  Bias->setVisibility(GlobalVariable::HiddenVisibility);
+  // A definition that's weak (linkonce_odr) without being in a COMDAT
+  // section wouldn't lead to link errors, but it would lead to a dead
+  // data word from every TU but one. Putting it in COMDAT ensures there
+  // will be exactly one data slot in the link.
+  if (TT.supportsCOMDAT())
+    Bias->setComdat(M.getOrInsertComdat(VarName));
+
+  return Bias;
+}
+
 Value *InstrLowerer::getCounterAddress(InstrProfCntrInstBase *I) {
   auto *Counters = getOrCreateRegionCounters(I);
   IRBuilder<> Builder(I);
@@ -903,22 +930,7 @@ Value *InstrLowerer::getCounterAddress(InstrProfCntrInstBase *I) {
   LoadInst *&BiasLI = FunctionToProfileBiasMap[Fn];
   if (!BiasLI) {
     IRBuilder<> EntryBuilder(&Fn->getEntryBlock().front());
-    auto *Bias = M.getGlobalVariable(getInstrProfCounterBiasVarName());
-    if (!Bias) {
-      // Compiler must define this variable when runtime counter relocation
-      // is being used. Runtime has a weak external reference that is used
-      // to check whether that's the case or not.
-      Bias = new GlobalVariable(
-          M, Int64Ty, false, GlobalValue::LinkOnceODRLinkage,
-          Constant::getNullValue(Int64Ty), getInstrProfCounterBiasVarName());
-      Bias->setVisibility(GlobalVariable::HiddenVisibility);
-      // A definition that's weak (linkonce_odr) without being in a COMDAT
-      // section wouldn't lead to link errors, but it would lead to a dead
-      // data word from every TU but one. Putting it in COMDAT ensures there
-      // will be exactly one data slot in the link.
-      if (TT.supportsCOMDAT())
-        Bias->setComdat(M.getOrInsertComdat(Bias->getName()));
-    }
+    auto *Bias = getOrCreateBiasVar(getInstrProfCounterBiasVarName());
     BiasLI = EntryBuilder.CreateLoad(Int64Ty, Bias);
   }
   auto *Add = Builder.CreateAdd(Builder.CreatePtrToInt(Addr, Int64Ty), BiasLI);

>From 9b47d563db8faec8febf3b6b1c7cfbcb7d190155 Mon Sep 17 00:00:00 2001
From: NAKAMURA Takumi <geek4civic at gmail.com>
Date: Tue, 18 Jun 2024 11:20:15 +0900
Subject: [PATCH 2/2] Prune "pgocount"

---
 llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
index 213044800053f..c5120a9d779c8 100644
--- a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
+++ b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
@@ -986,7 +986,7 @@ void InstrLowerer::lowerIncrement(InstrProfIncrementInst *Inc) {
                             MaybeAlign(), AtomicOrdering::Monotonic);
   } else {
     Value *IncStep = Inc->getStep();
-    Value *Load = Builder.CreateLoad(IncStep->getType(), Addr, "pgocount");
+    Value *Load = Builder.CreateLoad(IncStep->getType(), Addr);
     auto *Count = Builder.CreateAdd(Load, Inc->getStep());
     auto *Store = Builder.CreateStore(Count, Addr);
     if (isCounterPromotionEnabled())