diff --git a/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp b/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp
--- a/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp
@@ -723,13 +723,11 @@
 unsigned GCNSubtarget::getReservedNumSGPRs(const Function &F) const {
   // The logic to detect if the function has
   // flat scratch init is same as how MachineFunctionInfo derives.
+  bool isEntry = AMDGPU::isEntryFunctionCC(F.getCallingConv());
   bool FunctionHasFlatScratchInit = false;
-  bool HasCalls = F.hasFnAttribute("amdgpu-calls");
-  bool HasStackObjects = F.hasFnAttribute("amdgpu-stack-objects");
-  if (hasFlatAddressSpace() && AMDGPU::isEntryFunctionCC(F.getCallingConv()) &&
-      (isAmdHsaOrMesa(F) || enableFlatScratch()) &&
-      !flatScratchIsArchitected()) {
-    if (HasCalls || HasStackObjects || enableFlatScratch())
+  if (hasFlatAddressSpace() && isEntry && !flatScratchIsArchitected() &&
+      (isAmdHsaOrMesa(F) || enableFlatScratch())) {
+    if (enableFlatScratch())
       FunctionHasFlatScratchInit = true;
   }
   return getBaseReservedNumSGPRs(FunctionHasFlatScratchInit);