[PATCH] D147492: [IR] Remove uses of the oddly named ConstantFP::getZeroValueForNegation in integer code.

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.
craig.topper added reviewers: nikic, reames, efriedma.
Herald added subscribers: StephenFan, hiraditya.
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Herald added a project: LLVM.

Confusingly ConstantFP's getZeroValueForNegation intentionally
handles non-FP constants. It calls getNullValue in Constant.

Nearly all uses in tree are for integers rather than FP. Maybe due
to replacing FSub -0.0, X idiom with an FNeg instructions a few
years ago.

This patch replaces all the integer uses in tree with ConstantInt::get(0, Ty).

The one remaining use is in clang with a FIXME that it should use fneg.
Maybe I'll fix that next and delete ConstantFP::getZeroValueForNegation.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D147492

Files:
  llvm/lib/IR/Constants.cpp
  llvm/lib/IR/Instructions.cpp


Index: llvm/lib/IR/Instructions.cpp
===================================================================
--- llvm/lib/IR/Instructions.cpp
+++ llvm/lib/IR/Instructions.cpp
@@ -3073,42 +3073,42 @@
 
 BinaryOperator *BinaryOperator::CreateNeg(Value *Op, const Twine &Name,
                                           Instruction *InsertBefore) {
-  Value *zero = ConstantFP::getZeroValueForNegation(Op->getType());
+  Value *Zero = ConstantInt::get(Op->getType(), 0);
   return new BinaryOperator(Instruction::Sub,
-                            zero, Op,
+                            Zero, Op,
                             Op->getType(), Name, InsertBefore);
 }
 
 BinaryOperator *BinaryOperator::CreateNeg(Value *Op, const Twine &Name,
                                           BasicBlock *InsertAtEnd) {
-  Value *zero = ConstantFP::getZeroValueForNegation(Op->getType());
+  Value *Zero = ConstantInt::get(Op->getType(), 0);
   return new BinaryOperator(Instruction::Sub,
-                            zero, Op,
+                            Zero, Op,
                             Op->getType(), Name, InsertAtEnd);
 }
 
 BinaryOperator *BinaryOperator::CreateNSWNeg(Value *Op, const Twine &Name,
                                              Instruction *InsertBefore) {
-  Value *zero = ConstantFP::getZeroValueForNegation(Op->getType());
-  return BinaryOperator::CreateNSWSub(zero, Op, Name, InsertBefore);
+  Value *Zero = ConstantInt::get(Op->getType(), 0);
+  return BinaryOperator::CreateNSWSub(Zero, Op, Name, InsertBefore);
 }
 
 BinaryOperator *BinaryOperator::CreateNSWNeg(Value *Op, const Twine &Name,
                                              BasicBlock *InsertAtEnd) {
-  Value *zero = ConstantFP::getZeroValueForNegation(Op->getType());
-  return BinaryOperator::CreateNSWSub(zero, Op, Name, InsertAtEnd);
+  Value *Zero = ConstantInt::get(Op->getType(), 0);
+  return BinaryOperator::CreateNSWSub(Zero, Op, Name, InsertAtEnd);
 }
 
 BinaryOperator *BinaryOperator::CreateNUWNeg(Value *Op, const Twine &Name,
                                              Instruction *InsertBefore) {
-  Value *zero = ConstantFP::getZeroValueForNegation(Op->getType());
-  return BinaryOperator::CreateNUWSub(zero, Op, Name, InsertBefore);
+  Value *Zero = ConstantInt::get(Op->getType(), 0);
+  return BinaryOperator::CreateNUWSub(Zero, Op, Name, InsertBefore);
 }
 
 BinaryOperator *BinaryOperator::CreateNUWNeg(Value *Op, const Twine &Name,
                                              BasicBlock *InsertAtEnd) {
-  Value *zero = ConstantFP::getZeroValueForNegation(Op->getType());
-  return BinaryOperator::CreateNUWSub(zero, Op, Name, InsertAtEnd);
+  Value *Zero = ConstantInt::get(Op->getType(), 0);
+  return BinaryOperator::CreateNUWSub(Zero, Op, Name, InsertAtEnd);
 }
 
 BinaryOperator *BinaryOperator::CreateNot(Value *Op, const Twine &Name,
Index: llvm/lib/IR/Constants.cpp
===================================================================
--- llvm/lib/IR/Constants.cpp
+++ llvm/lib/IR/Constants.cpp
@@ -2601,8 +2601,7 @@
 Constant *ConstantExpr::getNeg(Constant *C, bool HasNUW, bool HasNSW) {
   assert(C->getType()->isIntOrIntVectorTy() &&
          "Cannot NEG a nonintegral value!");
-  return getSub(ConstantFP::getZeroValueForNegation(C->getType()),
-                C, HasNUW, HasNSW);
+  return getSub(ConstantInt::get(C->getType(), 0), C, HasNUW, HasNSW);
 }
 
 Constant *ConstantExpr::getNot(Constant *C) {


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