[llvm] a7ed55f - [AMDGPU] Simplify getReservedNumSGPRs

[via llvm-commits]

Author: madhur13490
Date: 2021-06-30T16:19:39+05:30
New Revision: a7ed55f64c5fdce9af3257458779402fb9de1f8b

URL: https://github.com/llvm/llvm-project/commit/a7ed55f64c5fdce9af3257458779402fb9de1f8b
DIFF: https://github.com/llvm/llvm-project/commit/a7ed55f64c5fdce9af3257458779402fb9de1f8b.diff

LOG: [AMDGPU] Simplify getReservedNumSGPRs

This is a followup patch on D103636 where
it seemed checking on amdgpu-calls and
amdgpu-stack-objects is unnecessary. Removing these
checks didn't regress any tests functionally.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D104513

Added: 
    

Modified: 
    llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp b/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp
index 37480ffbf05a..e67a76eeb4cb 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp
@@ -821,15 +821,17 @@ unsigned GCNSubtarget::getReservedNumSGPRs(const MachineFunction &MF) const {
 
 unsigned GCNSubtarget::getReservedNumSGPRs(const Function &F) const {
   // The logic to detect if the function has
-  // flat scratch init is same as how MachineFunctionInfo derives.
+  // flat scratch init is slightly 
diff erent than how
+  // SIMachineFunctionInfo constructor derives.
+  // We don't use amdgpu-calls, amdgpu-stack-objects
+  // attributes and isAmdHsaOrMesa here as it doesn't really matter.
+  // TODO: Outline this derivation logic and have just
+  // one common function in the backend to avoid duplication.
+  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())
-      FunctionHasFlatScratchInit = true;
+  if (hasFlatAddressSpace() && isEntry && !flatScratchIsArchitected() &&
+      enableFlatScratch()) {
+    FunctionHasFlatScratchInit = true;
   }
   return getBaseReservedNumSGPRs(FunctionHasFlatScratchInit);
 }