[llvm] [IR] Strip dead code post ConstExpr removals (NFC) (PR #139524)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-ir

Author: Ramkumar Ramachandra (artagnon)

<details>
<summary>Changes</summary>

Strip dead code in Operator.h related to the removal of several constant expressions. Note that PossiblyExactOperator can no longer be a ConstantExpr.

---
Full diff: https://github.com/llvm/llvm-project/pull/139524.diff


1 Files Affected:

- (modified) llvm/include/llvm/IR/Operator.h (+3-9) 


``````````diff
diff --git a/llvm/include/llvm/IR/Operator.h b/llvm/include/llvm/IR/Operator.h
index 4d77860be994e..38f84647ec74e 100644
--- a/llvm/include/llvm/IR/Operator.h
+++ b/llvm/include/llvm/IR/Operator.h
@@ -134,9 +134,7 @@ class OverflowingBinaryOperator : public Operator {
   }
   static bool classof(const ConstantExpr *CE) {
     return CE->getOpcode() == Instruction::Add ||
-           CE->getOpcode() == Instruction::Sub ||
-           CE->getOpcode() == Instruction::Mul ||
-           CE->getOpcode() == Instruction::Shl;
+           CE->getOpcode() == Instruction::Sub;
   }
   static bool classof(const Value *V) {
     return (isa<Instruction>(V) && classof(cast<Instruction>(V))) ||
@@ -150,7 +148,7 @@ struct OperandTraits<OverflowingBinaryOperator>
 
 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(OverflowingBinaryOperator, Value)
 
-/// A udiv or sdiv instruction, which can be marked as "exact",
+/// A udiv, sdiv, lshr, or ashr instruction, which can be marked as "exact",
 /// indicating that no bits are destroyed.
 class PossiblyExactOperator : public Operator {
 public:
@@ -182,15 +180,11 @@ class PossiblyExactOperator : public Operator {
            OpC == Instruction::LShr;
   }
 
-  static bool classof(const ConstantExpr *CE) {
-    return isPossiblyExactOpcode(CE->getOpcode());
-  }
   static bool classof(const Instruction *I) {
     return isPossiblyExactOpcode(I->getOpcode());
   }
   static bool classof(const Value *V) {
-    return (isa<Instruction>(V) && classof(cast<Instruction>(V))) ||
-           (isa<ConstantExpr>(V) && classof(cast<ConstantExpr>(V)));
+    return (isa<Instruction>(V) && classof(cast<Instruction>(V)));
   }
 };
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/139524