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

Strip dead code in Operator.h related to the removal of several constant
expressions. Note that PossiblyExactOperator can no longer be a
ConstantExpr.
@artagnon artagnon requested a review from nikic May 12, 2025 10:05
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llvmbot commented May 12, 2025

@llvm/pr-subscribers-llvm-ir

Author: Ramkumar Ramachandra (artagnon)

Changes

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 --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)));
   }
 };
 

@artagnon
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Gentle ping.

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@nikic nikic left a comment

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LGTM, see also #72501.

@artagnon artagnon merged commit 2804643 into llvm:main May 22, 2025
13 checks passed
@artagnon artagnon deleted the ir-dead-code-constexpr branch May 22, 2025 16:35
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3 participants