[llvm] AMDGPU: Avoid double attribute lookup for register count attributes (PR #127782)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-amdgpu

Author: Matt Arsenault (arsenm)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/127782.diff


1 Files Affected:

- (modified) llvm/lib/Target/AMDGPU/GCNSubtarget.cpp (+6-7) 


``````````diff
diff --git a/llvm/lib/Target/AMDGPU/GCNSubtarget.cpp b/llvm/lib/Target/AMDGPU/GCNSubtarget.cpp
index b5e8e246825c7..55af5826e90d0 100644
--- a/llvm/lib/Target/AMDGPU/GCNSubtarget.cpp
+++ b/llvm/lib/Target/AMDGPU/GCNSubtarget.cpp
@@ -422,10 +422,10 @@ unsigned GCNSubtarget::getBaseMaxNumSGPRs(
 
   // Check if maximum number of SGPRs was explicitly requested using
   // "amdgpu-num-sgpr" attribute.
-  if (F.hasFnAttribute("amdgpu-num-sgpr")) {
-    unsigned Requested =
-        F.getFnAttributeAsParsedInteger("amdgpu-num-sgpr", MaxNumSGPRs);
+  unsigned Requested =
+      F.getFnAttributeAsParsedInteger("amdgpu-num-sgpr", MaxNumSGPRs);
 
+  if (Requested != MaxNumSGPRs) {
     // Make sure requested value does not violate subtarget's specifications.
     if (Requested && (Requested <= ReservedNumSGPRs))
       Requested = 0;
@@ -504,10 +504,9 @@ unsigned GCNSubtarget::getBaseMaxNumVGPRs(
 
   // Check if maximum number of VGPRs was explicitly requested using
   // "amdgpu-num-vgpr" attribute.
-  if (F.hasFnAttribute("amdgpu-num-vgpr")) {
-    unsigned Requested =
-        F.getFnAttributeAsParsedInteger("amdgpu-num-vgpr", MaxNumVGPRs);
-
+  unsigned Requested =
+      F.getFnAttributeAsParsedInteger("amdgpu-num-vgpr", MaxNumVGPRs);
+  if (Requested != MaxNumVGPRs) {
     if (hasGFX90AInsts())
       Requested *= 2;
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/127782