[IR] Remove createReplacementInstr. NFC.

It is unused since D112791.

Differential Revision: https://reviews.llvm.org/D112795

Author: jayfoad

llvm/include/llvm/IR/ReplaceConstant.h

@@ -21,10 +21,6 @@
 
 namespace llvm {
 
-/// Create a replacement instruction for constant expression \p CE and insert
-/// it before \p Instr.
-Instruction *createReplacementInstr(ConstantExpr *CE, Instruction *Instr);
-
 /// The given instruction \p I contains given constant expression \p CE as one
 /// of its operands, possibly nested within constant expression trees. Convert
 /// all reachable paths from contant expression operands of \p I to \p CE into

llvm/lib/IR/ReplaceConstant.cpp

@@ -17,11 +17,6 @@
 #include "llvm/IR/NoFolder.h"
 
 namespace llvm {
-// Replace a constant expression by instructions with equivalent operations at
-// a specified location.
-Instruction *createReplacementInstr(ConstantExpr *CE, Instruction *Instr) {
-  return CE->getAsInstruction(Instr);
-}
 
 void convertConstantExprsToInstructions(Instruction *I, ConstantExpr *CE,
                                         SmallPtrSetImpl<Instruction *> *Insts) {