[AMDGPU] Rename LocalMemorySize features to AddressableLocalMemorySize (#110242)

Change the names of the TableGen features to match the names used by
AMDGPUSubtarget. "Addressable" refers to the amount that can be accessed
by a single workgroup. Add some explanatory comments. NFC.

Author: jayfoad

llvm/lib/Target/AMDGPU/AMDGPU.td

@@ -1118,7 +1118,7 @@ class GCNSubtargetFeatureGeneration <string Value,
 
 def FeatureSouthernIslands : GCNSubtargetFeatureGeneration<"SOUTHERN_ISLANDS",
     "southern-islands",
-  [FeatureFP64, FeatureLocalMemorySize32768, FeatureMIMG_R128,
+  [FeatureFP64, FeatureAddressableLocalMemorySize32768, FeatureMIMG_R128,
   FeatureWavefrontSize64, FeatureSMemTimeInst, FeatureMadMacF32Insts,
   FeatureDsSrc2Insts, FeatureLDSBankCount32, FeatureMovrel,
   FeatureTrigReducedRange, FeatureExtendedImageInsts, FeatureImageInsts,
@@ -1130,7 +1130,7 @@ def FeatureSouthernIslands : GCNSubtargetFeatureGeneration<"SOUTHERN_ISLANDS",
 
 def FeatureSeaIslands : GCNSubtargetFeatureGeneration<"SEA_ISLANDS",
     "sea-islands",
-  [FeatureFP64, FeatureLocalMemorySize65536, FeatureMIMG_R128,
+  [FeatureFP64, FeatureAddressableLocalMemorySize65536, FeatureMIMG_R128,
   FeatureWavefrontSize64, FeatureFlatAddressSpace,
   FeatureCIInsts, FeatureMovrel, FeatureTrigReducedRange,
   FeatureGFX7GFX8GFX9Insts, FeatureSMemTimeInst, FeatureMadMacF32Insts,
@@ -1144,7 +1144,7 @@ def FeatureSeaIslands : GCNSubtargetFeatureGeneration<"SEA_ISLANDS",
 
 def FeatureVolcanicIslands : GCNSubtargetFeatureGeneration<"VOLCANIC_ISLANDS",
   "volcanic-islands",
-  [FeatureFP64, FeatureLocalMemorySize65536, FeatureMIMG_R128,
+  [FeatureFP64, FeatureAddressableLocalMemorySize65536, FeatureMIMG_R128,
    FeatureWavefrontSize64, FeatureFlatAddressSpace,
    FeatureGCN3Encoding, FeatureCIInsts, Feature16BitInsts,
    FeatureSMemRealTime, FeatureVGPRIndexMode, FeatureMovrel,
@@ -1160,7 +1160,7 @@ def FeatureVolcanicIslands : GCNSubtargetFeatureGeneration<"VOLCANIC_ISLANDS",
 
 def FeatureGFX9 : GCNSubtargetFeatureGeneration<"GFX9",
   "gfx9",
-  [FeatureFP64, FeatureLocalMemorySize65536,
+  [FeatureFP64, FeatureAddressableLocalMemorySize65536,
    FeatureWavefrontSize64, FeatureFlatAddressSpace,
    FeatureGCN3Encoding, FeatureCIInsts, Feature16BitInsts,
    FeatureSMemRealTime, FeatureScalarStores, FeatureInv2PiInlineImm,
@@ -1179,7 +1179,7 @@ def FeatureGFX9 : GCNSubtargetFeatureGeneration<"GFX9",
 
 def FeatureGFX10 : GCNSubtargetFeatureGeneration<"GFX10",
   "gfx10",
-  [FeatureFP64, FeatureLocalMemorySize65536, FeatureMIMG_R128,
+  [FeatureFP64, FeatureAddressableLocalMemorySize65536, FeatureMIMG_R128,
    FeatureFlatAddressSpace,
    FeatureCIInsts, Feature16BitInsts,
    FeatureSMemRealTime, FeatureInv2PiInlineImm,
@@ -1203,7 +1203,7 @@ def FeatureGFX10 : GCNSubtargetFeatureGeneration<"GFX10",
 
 def FeatureGFX11 : GCNSubtargetFeatureGeneration<"GFX11",
   "gfx11",
-  [FeatureFP64, FeatureLocalMemorySize65536, FeatureMIMG_R128,
+  [FeatureFP64, FeatureAddressableLocalMemorySize65536, FeatureMIMG_R128,
    FeatureFlatAddressSpace, Feature16BitInsts,
    FeatureInv2PiInlineImm, FeatureApertureRegs,
    FeatureCIInsts, FeatureGFX8Insts, FeatureGFX9Insts, FeatureGFX10Insts,
@@ -1226,7 +1226,7 @@ def FeatureGFX11 : GCNSubtargetFeatureGeneration<"GFX11",
 
 def FeatureGFX12 : GCNSubtargetFeatureGeneration<"GFX12",
   "gfx12",
-  [FeatureFP64, FeatureLocalMemorySize65536, FeatureMIMG_R128,
+  [FeatureFP64, FeatureAddressableLocalMemorySize65536, FeatureMIMG_R128,
    FeatureFlatAddressSpace, Feature16BitInsts,
    FeatureInv2PiInlineImm, FeatureApertureRegs,
    FeatureCIInsts, FeatureGFX8Insts, FeatureGFX9Insts, FeatureGFX10Insts,

llvm/lib/Target/AMDGPU/AMDGPUFeatures.td

@@ -18,15 +18,17 @@ def FeatureFMA : SubtargetFeature<"fmaf",
   "Enable single precision FMA (not as fast as mul+add, but fused)"
 >;
 
-class SubtargetFeatureLocalMemorySize <int Value> : SubtargetFeature<
-  "localmemorysize"#Value,
-  "LocalMemorySize",
+// Addressable local memory size is the maximum number of bytes of LDS that can
+// be allocated to a single workgroup.
+class SubtargetFeatureAddressableLocalMemorySize <int Value> : SubtargetFeature<
+  "addressablelocalmemorysize"#Value,
+  "AddressableLocalMemorySize",
   !cast<string>(Value),
   "The size of local memory in bytes"
 >;
 
-def FeatureLocalMemorySize32768 : SubtargetFeatureLocalMemorySize<32768>;
-def FeatureLocalMemorySize65536 : SubtargetFeatureLocalMemorySize<65536>;
+def FeatureAddressableLocalMemorySize32768 : SubtargetFeatureAddressableLocalMemorySize<32768>;
+def FeatureAddressableLocalMemorySize65536 : SubtargetFeatureAddressableLocalMemorySize<65536>;
 
 class SubtargetFeatureWavefrontSize <int ValueLog2> : SubtargetFeature<
   "wavefrontsize"#!shl(1, ValueLog2),

llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h

@@ -226,10 +226,18 @@ class AMDGPUSubtarget {
     return WavefrontSizeLog2;
   }
 
+  /// Return the maximum number of bytes of LDS available for all workgroups
+  /// running on the same WGP or CU.
+  /// For GFX10-GFX12 in WGP mode this is 128k even though each workgroup is
+  /// limited to 64k.
   unsigned getLocalMemorySize() const {
     return LocalMemorySize;
   }
 
+  /// Return the maximum number of bytes of LDS that can be allocated to a
+  /// single workgroup.
+  /// For GFX10-GFX12 in WGP mode this is limited to 64k even though the WGP has
+  /// 128k in total.
   unsigned getAddressableLocalMemorySize() const {
     return AddressableLocalMemorySize;
   }

llvm/lib/Target/AMDGPU/GCNSubtarget.cpp

@@ -143,11 +143,10 @@ GCNSubtarget &GCNSubtarget::initializeSubtargetDependencies(const Triple &TT,
   if (LDSBankCount == 0)
     LDSBankCount = 32;
 
-  if (TT.getArch() == Triple::amdgcn && LocalMemorySize == 0)
-    LocalMemorySize = 32768;
-
-  AddressableLocalMemorySize = LocalMemorySize;
+  if (TT.getArch() == Triple::amdgcn && AddressableLocalMemorySize == 0)
+    AddressableLocalMemorySize = 32768;
 
+  LocalMemorySize = AddressableLocalMemorySize;
   if (AMDGPU::isGFX10Plus(*this) &&
       !getFeatureBits().test(AMDGPU::FeatureCuMode))
     LocalMemorySize *= 2;

llvm/lib/Target/AMDGPU/R600Processors.td

@@ -53,13 +53,13 @@ def FeatureR700 : R600SubtargetFeatureGeneration<"R700", "r700",
 >;
 
 def FeatureEvergreen : R600SubtargetFeatureGeneration<"EVERGREEN", "evergreen",
-  [FeatureFetchLimit16, FeatureLocalMemorySize32768]
+  [FeatureFetchLimit16, FeatureAddressableLocalMemorySize32768]
 >;
 
 def FeatureNorthernIslands : R600SubtargetFeatureGeneration<"NORTHERN_ISLANDS",
   "northern-islands",
   [FeatureFetchLimit16, FeatureWavefrontSize64,
-   FeatureLocalMemorySize32768]
+   FeatureAddressableLocalMemorySize32768]
 >;
 
 

llvm/lib/Target/AMDGPU/R600Subtarget.cpp

@@ -29,7 +29,7 @@ R600Subtarget::R600Subtarget(const Triple &TT, StringRef GPU, StringRef FS,
       FrameLowering(TargetFrameLowering::StackGrowsUp, getStackAlignment(), 0),
       TLInfo(TM, initializeSubtargetDependencies(TT, GPU, FS)),
       InstrItins(getInstrItineraryForCPU(GPU)) {
-  AddressableLocalMemorySize = LocalMemorySize;
+  LocalMemorySize = AddressableLocalMemorySize;
 }
 
 R600Subtarget &R600Subtarget::initializeSubtargetDependencies(const Triple &TT,

llvm/lib/Target/AMDGPU/Utils/AMDGPUBaseInfo.cpp

@@ -911,9 +911,9 @@ unsigned getLocalMemorySize(const MCSubtargetInfo *STI) {
 }
 
 unsigned getAddressableLocalMemorySize(const MCSubtargetInfo *STI) {
-  if (STI->getFeatureBits().test(FeatureLocalMemorySize32768))
+  if (STI->getFeatureBits().test(FeatureAddressableLocalMemorySize32768))
     return 32768;
-  if (STI->getFeatureBits().test(FeatureLocalMemorySize65536))
+  if (STI->getFeatureBits().test(FeatureAddressableLocalMemorySize65536))
     return 65536;
   return 0;
 }