Move CodeGenFunction::EmitScalarOrConstFoldImmArg; NFC (llvm#170286)

This function is called from various .cpp files under `TargetBuiltins/`,
and was moved unintentionally into `AMDGPU.cpp` in PR llvm#132252. Move it
to a common place.

Author: svenvh

clang/lib/CodeGen/CodeGenFunction.cpp

@@ -2158,6 +2158,23 @@ void CodeGenFunction::EmitBranchOnBoolExpr(
   }
 }
 
+llvm::Value *CodeGenFunction::EmitScalarOrConstFoldImmArg(unsigned ICEArguments,
+                                                          unsigned Idx,
+                                                          const CallExpr *E) {
+  llvm::Value *Arg = nullptr;
+  if ((ICEArguments & (1 << Idx)) == 0) {
+    Arg = EmitScalarExpr(E->getArg(Idx));
+  } else {
+    // If this is required to be a constant, constant fold it so that we
+    // know that the generated intrinsic gets a ConstantInt.
+    std::optional<llvm::APSInt> Result =
+        E->getArg(Idx)->getIntegerConstantExpr(getContext());
+    assert(Result && "Expected argument to be a constant");
+    Arg = llvm::ConstantInt::get(getLLVMContext(), *Result);
+  }
+  return Arg;
+}
+
 /// ErrorUnsupported - Print out an error that codegen doesn't support the
 /// specified stmt yet.
 void CodeGenFunction::ErrorUnsupported(const Stmt *S, const char *Type) {

clang/lib/CodeGen/TargetBuiltins/AMDGPU.cpp

@@ -343,23 +343,6 @@ void CodeGenFunction::ProcessOrderScopeAMDGCN(Value *Order, Value *Scope,
     SSID = getLLVMContext().getOrInsertSyncScopeID(SSN);
 }
 
-llvm::Value *CodeGenFunction::EmitScalarOrConstFoldImmArg(unsigned ICEArguments,
-                                                          unsigned Idx,
-                                                          const CallExpr *E) {
-  llvm::Value *Arg = nullptr;
-  if ((ICEArguments & (1 << Idx)) == 0) {
-    Arg = EmitScalarExpr(E->getArg(Idx));
-  } else {
-    // If this is required to be a constant, constant fold it so that we
-    // know that the generated intrinsic gets a ConstantInt.
-    std::optional<llvm::APSInt> Result =
-        E->getArg(Idx)->getIntegerConstantExpr(getContext());
-    assert(Result && "Expected argument to be a constant");
-    Arg = llvm::ConstantInt::get(getLLVMContext(), *Result);
-  }
-  return Arg;
-}
-
 void CodeGenFunction::AddAMDGPUFenceAddressSpaceMMRA(llvm::Instruction *Inst,
                                                      const CallExpr *E) {
   constexpr const char *Tag = "amdgpu-synchronize-as";