diff --git a/flang/include/flang/Optimizer/Builder/LowLevelIntrinsics.h b/flang/include/flang/Optimizer/Builder/LowLevelIntrinsics.h
index 45499906e39f..9303f09d42fb 100644
--- a/flang/include/flang/Optimizer/Builder/LowLevelIntrinsics.h
+++ b/flang/include/flang/Optimizer/Builder/LowLevelIntrinsics.h
@@ -24,9 +24,6 @@ class FirOpBuilder;
 
 namespace fir::factory {
 
-/// Get the LLVM intrinsic for `memset`. Use the 64 bit version.
-mlir::func::FuncOp getLlvmMemset(FirOpBuilder &builder);
-
 /// Get the C standard library `realloc` function.
 mlir::func::FuncOp getRealloc(FirOpBuilder &builder);
 
diff --git a/flang/lib/Optimizer/Builder/LowLevelIntrinsics.cpp b/flang/lib/Optimizer/Builder/LowLevelIntrinsics.cpp
index 73fd8fa0c2b6..64d70d70829f 100644
--- a/flang/lib/Optimizer/Builder/LowLevelIntrinsics.cpp
+++ b/flang/lib/Optimizer/Builder/LowLevelIntrinsics.cpp
@@ -21,16 +21,6 @@
 #include "flang/Optimizer/Builder/LowLevelIntrinsics.h"
 #include "flang/Optimizer/Builder/FIRBuilder.h"
 
-mlir::func::FuncOp fir::factory::getLlvmMemset(fir::FirOpBuilder &builder) {
-  auto ptrTy = builder.getRefType(builder.getIntegerType(8));
-  llvm::SmallVector<mlir::Type> args = {ptrTy, ptrTy, builder.getI64Type(),
-                                        builder.getI1Type()};
-  auto memsetTy =
-      mlir::FunctionType::get(builder.getContext(), args, std::nullopt);
-  return builder.createFunction(builder.getUnknownLoc(),
-                                "llvm.memset.p0.p0.i64", memsetTy);
-}
-
 mlir::func::FuncOp fir::factory::getRealloc(fir::FirOpBuilder &builder) {
   auto ptrTy = builder.getRefType(builder.getIntegerType(8));
   llvm::SmallVector<mlir::Type> args = {ptrTy, builder.getI64Type()};