[llvm] [NFC][InstCombine] Make use of `unknown` profile info clear in the API name (PR #162766)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Mircea Trofin (mtrofin)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/162766.diff


5 Files Affected:

- (modified) llvm/include/llvm/IR/Instructions.h (+1-1) 
- (modified) llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp (+4-2) 
- (modified) llvm/lib/Transforms/InstCombine/InstCombineInternal.h (+16-7) 
- (modified) llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp (+2-1) 
- (modified) llvm/lib/Transforms/InstCombine/InstructionCombining.cpp (+1-1) 


``````````diff
diff --git a/llvm/include/llvm/IR/Instructions.h b/llvm/include/llvm/IR/Instructions.h
index de7a237098594..27930bbc651bd 100644
--- a/llvm/include/llvm/IR/Instructions.h
+++ b/llvm/include/llvm/IR/Instructions.h
@@ -1715,7 +1715,7 @@ class SelectInst : public Instruction {
   static SelectInst *Create(Value *C, Value *S1, Value *S2,
                             const Twine &NameStr = "",
                             InsertPosition InsertBefore = nullptr,
-                            Instruction *MDFrom = nullptr) {
+                            const Instruction *MDFrom = nullptr) {
     SelectInst *Sel =
         new (AllocMarker) SelectInst(C, S1, S2, NameStr, InsertBefore);
     if (MDFrom)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index 59e103cda0230..73ec4514f8414 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -880,11 +880,13 @@ Instruction *InstCombinerImpl::foldAddWithConstant(BinaryOperator &Add) {
   // zext(bool) + C -> bool ? C + 1 : C
   if (match(Op0, m_ZExt(m_Value(X))) &&
       X->getType()->getScalarSizeInBits() == 1)
-    return createSelectInst(X, InstCombiner::AddOne(Op1C), Op1);
+    return createSelectInstWithUnknownProfile(X, InstCombiner::AddOne(Op1C),
+                                              Op1);
   // sext(bool) + C -> bool ? C - 1 : C
   if (match(Op0, m_SExt(m_Value(X))) &&
       X->getType()->getScalarSizeInBits() == 1)
-    return createSelectInst(X, InstCombiner::SubOne(Op1C), Op1);
+    return createSelectInstWithUnknownProfile(X, InstCombiner::SubOne(Op1C),
+                                              Op1);
 
   // ~X + C --> (C-1) - X
   if (match(Op0, m_Not(m_Value(X)))) {
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
index e01c145bf5de3..71f96f37832b3 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
+++ b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
@@ -470,15 +470,24 @@ class LLVM_LIBRARY_VISIBILITY InstCombinerImpl final
   Value *simplifyNonNullOperand(Value *V, bool HasDereferenceable,
                                 unsigned Depth = 0);
 
+  /// Create `select C, S1, S2` and copy metadata from MDFrom.
   SelectInst *createSelectInst(Value *C, Value *S1, Value *S2,
+                               const Instruction &MDFrom,
                                const Twine &NameStr = "",
-                               InsertPosition InsertBefore = nullptr,
-                               Instruction *MDFrom = nullptr) {
-    SelectInst *SI =
-        SelectInst::Create(C, S1, S2, NameStr, InsertBefore, MDFrom);
-    if (!MDFrom)
-      setExplicitlyUnknownBranchWeightsIfProfiled(*SI, F, DEBUG_TYPE);
-    return SI;
+                               InsertPosition InsertBefore = nullptr) {
+    return SelectInst::Create(C, S1, S2, NameStr, InsertBefore, &MDFrom);
+  }
+
+  /// Use instead of createSelectInst if the profile cannot be calculated from
+  /// existing profile metadata. If the Function has profiles, set the profile
+  /// of this select to "unknown".
+  SelectInst *
+  createSelectInstWithUnknownProfile(Value *C, Value *S1, Value *S2,
+                                     const Twine &NameStr = "",
+                                     InsertPosition InsertBefore = nullptr) {
+    auto *Sel = SelectInst::Create(C, S1, S2, NameStr, InsertBefore, nullptr);
+    setExplicitlyUnknownBranchWeightsIfProfiled(*Sel, F, DEBUG_TYPE);
+    return Sel;
   }
 
 public:
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp
index d457e0c7dd1c4..899a3c16554c9 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp
@@ -1253,7 +1253,8 @@ Instruction *InstCombinerImpl::visitShl(BinaryOperator &I) {
     // shl (zext i1 X), C1 --> select (X, 1 << C1, 0)
     if (match(Op0, m_ZExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)) {
       auto *NewC = Builder.CreateShl(ConstantInt::get(Ty, 1), C1);
-      return createSelectInst(X, NewC, ConstantInt::getNullValue(Ty));
+      return createSelectInstWithUnknownProfile(X, NewC,
+                                                ConstantInt::getNullValue(Ty));
     }
   }
 
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index d56a1af49ef32..82ac9033e1600 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -1737,7 +1737,7 @@ Instruction *InstCombinerImpl::foldBinopOfSextBoolToSelect(BinaryOperator &BO) {
   Constant *Zero = ConstantInt::getNullValue(BO.getType());
   Value *TVal = Builder.CreateBinOp(BO.getOpcode(), Ones, C);
   Value *FVal = Builder.CreateBinOp(BO.getOpcode(), Zero, C);
-  return createSelectInst(X, TVal, FVal);
+  return createSelectInstWithUnknownProfile(X, TVal, FVal);
 }
 
 static Value *simplifyOperationIntoSelectOperand(Instruction &I, SelectInst *SI,

``````````

</details>


https://github.com/llvm/llvm-project/pull/162766