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

[Matt Arsenault via llvm-commits]

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

None

>From 1af1628e611a7e57ae86b0c330d34b753b694164 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Wed, 19 Feb 2025 17:54:13 +0700
Subject: [PATCH] AMDGPU: Avoid double attribute lookup for register count
 attributes

---
 llvm/lib/Target/AMDGPU/GCNSubtarget.cpp | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

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;