Pull definition into header

Author: jayfoad

llvm/lib/Target/AMDGPU/GCNSubtarget.cpp

@@ -688,14 +688,6 @@ unsigned GCNSubtarget::getNSAThreshold(const MachineFunction &MF) const {
   return NSAThreshold;
 }
 
-unsigned GCNSubtarget::getSNopBits() const {
-  if (getGeneration() >= AMDGPUSubtarget::GFX12)
-    return 7;
-  if (getGeneration() >= AMDGPUSubtarget::VOLCANIC_ISLANDS)
-    return 4;
-  return 3;
-}
-
 GCNUserSGPRUsageInfo::GCNUserSGPRUsageInfo(const Function &F,
                                            const GCNSubtarget &ST)
     : ST(ST) {

llvm/lib/Target/AMDGPU/GCNSubtarget.h

@@ -1842,7 +1842,13 @@ class GCNSubtarget final : public AMDGPUGenSubtargetInfo,
 
   /// \returns the number of significant bits in the immediate field of the
   /// S_NOP instruction.
-  unsigned getSNopBits() const;
+  unsigned getSNopBits() const {
+    if (getGeneration() >= AMDGPUSubtarget::GFX12)
+      return 7;
+    if (getGeneration() >= AMDGPUSubtarget::VOLCANIC_ISLANDS)
+      return 4;
+    return 3;
+  }
 };
 
 class GCNUserSGPRUsageInfo {