[AMDGPU][MC] Add GFX12 SMEM encoding (#75215)

Author: mbrkusanin

llvm/lib/Target/AMDGPU/AMDGPU.td

@@ -411,6 +411,12 @@ def FeatureVGPRIndexMode : SubtargetFeature<"vgpr-index-mode",
   "Has VGPR mode register indexing"
 >;
 
+def FeatureScalarDwordx3Loads : SubtargetFeature<"scalar-dwordx3-loads",
+  "HasScalarDwordx3Loads",
+  "true",
+  "Has 96-bit scalar load instructions"
+>;
+
 def FeatureScalarStores : SubtargetFeature<"scalar-stores",
   "HasScalarStores",
   "true",
@@ -1462,7 +1468,8 @@ def FeatureISAVersion12 : FeatureSet<
    FeatureVcmpxPermlaneHazard,
    FeatureSALUFloatInsts,
    FeatureVGPRSingleUseHintInsts,
-   FeatureMADIntraFwdBug]>;
+   FeatureMADIntraFwdBug,
+   FeatureScalarDwordx3Loads]>;
 
 //===----------------------------------------------------------------------===//
 
@@ -2011,6 +2018,8 @@ def HasNoCvtFP8VOP1Bug : Predicate<"!Subtarget->hasCvtFP8VOP1Bug()">;
 
 def HasAtomicCSubNoRtnInsts : Predicate<"Subtarget->hasAtomicCSubNoRtnInsts()">;
 
+def HasScalarDwordx3Loads : Predicate<"Subtarget->hasScalarDwordx3Loads()">;
+
 // Include AMDGPU TD files
 include "SISchedule.td"
 include "GCNProcessors.td"

llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp

@@ -2635,7 +2635,7 @@ AMDGPUAsmParser::getRegularReg(RegisterKind RegKind,
   if (RegKind == IS_SGPR || RegKind == IS_TTMP) {
     // SGPR and TTMP registers must be aligned.
     // Max required alignment is 4 dwords.
-    AlignSize = std::min(RegWidth / 32, 4u);
+    AlignSize = std::min(llvm::bit_ceil(RegWidth / 32), 4u);
   }
 
   if (RegNum % AlignSize != 0) {

llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp

@@ -213,6 +213,7 @@ DECODE_OPERAND_REG_7(SReg_32_XM0_XEXEC, OPW32)
 DECODE_OPERAND_REG_7(SReg_32_XEXEC_HI, OPW32)
 DECODE_OPERAND_REG_7(SReg_64, OPW64)
 DECODE_OPERAND_REG_7(SReg_64_XEXEC, OPW64)
+DECODE_OPERAND_REG_7(SReg_96, OPW96)
 DECODE_OPERAND_REG_7(SReg_128, OPW128)
 DECODE_OPERAND_REG_7(SReg_256, OPW256)
 DECODE_OPERAND_REG_7(SReg_512, OPW512)
@@ -1239,6 +1240,8 @@ MCOperand AMDGPUDisassembler::createSRegOperand(unsigned SRegClassID,
   case AMDGPU::TTMP_64RegClassID:
     shift = 1;
     break;
+  case AMDGPU::SGPR_96RegClassID:
+  case AMDGPU::TTMP_96RegClassID:
   case AMDGPU::SGPR_128RegClassID:
   case AMDGPU::TTMP_128RegClassID:
   // ToDo: unclear if s[100:104] is available on VI. Can we use VCC as SGPR in

llvm/lib/Target/AMDGPU/GCNSubtarget.h

@@ -119,6 +119,7 @@ class GCNSubtarget final : public AMDGPUGenSubtargetInfo,
   bool HasFmaMixInsts = false;
   bool HasMovrel = false;
   bool HasVGPRIndexMode = false;
+  bool HasScalarDwordx3Loads = false;
   bool HasScalarStores = false;
   bool HasScalarAtomics = false;
   bool HasSDWAOmod = false;
@@ -889,6 +890,8 @@ class GCNSubtarget final : public AMDGPUGenSubtargetInfo,
     return getGeneration() >= VOLCANIC_ISLANDS;
   }
 
+  bool hasScalarDwordx3Loads() const { return HasScalarDwordx3Loads; }
+
   bool hasScalarStores() const {
     return HasScalarStores;
   }

llvm/lib/Target/AMDGPU/SIRegisterInfo.td

@@ -414,7 +414,7 @@ def SGPR_32 : SIRegisterClass<"AMDGPU", [i32, f32, i16, f16, v2i16, v2f16], 32,
 // SGPR 64-bit registers
 def SGPR_64Regs : SIRegisterTuples<getSubRegs<2>.ret, SGPR_32, 105, 2, 2, "s">;
 
-// SGPR 96-bit registers. No operations use these, but for symmetry with 96-bit VGPRs.
+// SGPR 96-bit registers.
 def SGPR_96Regs : SIRegisterTuples<getSubRegs<3>.ret, SGPR_32, 105, 4, 3, "s">;
 
 // SGPR 128-bit registers

llvm/lib/Target/AMDGPU/SMInstructions.td

@@ -74,7 +74,7 @@ class SM_Real <SM_Pseudo ps, string opName = ps.Mnemonic>
   bits<7>  sdst;
   bits<32> offset;
   bits<8>  soffset;
-  bits<5> cpol;
+  bits<5>  cpol;
 }
 
 class OffsetMode<bit hasOffset, bit hasSOffset, string variant,
@@ -300,6 +300,8 @@ multiclass SM_Pseudo_Atomics<RegisterClass baseClass,
 // does sdst for SMRD on SI/CI?
 defm S_LOAD_DWORD    : SM_Pseudo_Loads <SReg_64, SReg_32_XM0_XEXEC>;
 defm S_LOAD_DWORDX2  : SM_Pseudo_Loads <SReg_64, SReg_64_XEXEC>;
+let SubtargetPredicate = HasScalarDwordx3Loads in
+  defm S_LOAD_DWORDX3  : SM_Pseudo_Loads <SReg_64, SReg_96>;
 defm S_LOAD_DWORDX4  : SM_Pseudo_Loads <SReg_64, SReg_128>;
 defm S_LOAD_DWORDX8  : SM_Pseudo_Loads <SReg_64, SReg_256>;
 defm S_LOAD_DWORDX16 : SM_Pseudo_Loads <SReg_64, SReg_512>;
@@ -309,6 +311,8 @@ defm S_BUFFER_LOAD_DWORD : SM_Pseudo_Loads <SReg_128, SReg_32_XM0_XEXEC>;
 // FIXME: exec_lo/exec_hi appear to be allowed for SMRD loads on
 // SI/CI, bit disallowed for SMEM on VI.
 defm S_BUFFER_LOAD_DWORDX2 : SM_Pseudo_Loads <SReg_128, SReg_64_XEXEC>;
+let SubtargetPredicate = HasScalarDwordx3Loads in
+  defm S_BUFFER_LOAD_DWORDX3 : SM_Pseudo_Loads <SReg_128, SReg_96>;
 defm S_BUFFER_LOAD_DWORDX4 : SM_Pseudo_Loads <SReg_128, SReg_128>;
 defm S_BUFFER_LOAD_DWORDX8 : SM_Pseudo_Loads <SReg_128, SReg_256>;
 defm S_BUFFER_LOAD_DWORDX16 : SM_Pseudo_Loads <SReg_128, SReg_512>;
@@ -1179,7 +1183,7 @@ def SMInfoTable : GenericTable {
 class SMEM_Real_gfx11<bits<8> op, SM_Pseudo ps, string opName = ps.Mnemonic> :
     SMEM_Real_10Plus_common<op, ps, opName, SIEncodingFamily.GFX11,
                             SGPR_NULL_gfx11plus> {
-  let AssemblerPredicate = isGFX11Plus;
+  let AssemblerPredicate = isGFX11Only;
   let DecoderNamespace = "GFX11";
   let Inst{13}    = !if(ps.has_dlc, cpol{CPolBit.DLC}, 0);
   let Inst{14}    = !if(ps.has_glc, cpol{CPolBit.GLC}, 0);
@@ -1235,28 +1239,79 @@ defm S_ATC_PROBE_BUFFER : SM_Real_Probe_gfx11 <0x23>;
 // GFX12.
 //===----------------------------------------------------------------------===//
 
-class SMEM_Real_gfx12<bits<8> op, SM_Pseudo ps, string opName = ps.Mnemonic> :
-    SMEM_Real_10Plus_common<op, ps, opName, SIEncodingFamily.GFX12,
-                            SGPR_NULL_gfx11plus> {
+class SMEM_Real_gfx12Plus<bits<6> op, SM_Pseudo ps, string opName,
+                          int subtarget, RegisterWithSubRegs sgpr_null> :
+    SM_Real<ps, opName>, SIMCInstr<ps.PseudoInstr, subtarget>, Enc64 {
+
+  let Inst{18-13} = op;
+  let Inst{31-26} = 0x3d;
+
+  let Inst{55-32} = !if(ps.has_offset, offset{23-0}, !if(ps.has_soffset, 0, ?));
+  let Inst{63-57} = !if(ps.has_soffset, soffset{6-0},
+                        !if(ps.has_offset, sgpr_null.HWEncoding{6-0}, ?));
+}
+
+class SMEM_Real_gfx12<bits<6> op, SM_Pseudo ps, string opName = ps.Mnemonic> :
+    SMEM_Real_gfx12Plus<op, ps, opName, SIEncodingFamily.GFX12,
+                        SGPR_NULL_gfx11plus> {
   let AssemblerPredicate = isGFX12Plus;
   let DecoderNamespace = "GFX12";
-  let Inst{18-13} = op{5-0};
-  let Inst{19}    = !if(ps.has_dlc, cpol{CPolBit.DLC}, 0);
-  let Inst{24-20} = ?; // TODO-GFX12: Add new bits {24-20}: TH, Scope, NV
-  let Inst{25}    = !if(ps.has_glc, cpol{CPolBit.GLC}, 0);
-  let Inst{55-32} = offset{23-0};
+
+  let Inst{5-0}   = !if(ps.has_sbase, sbase{6-1}, ?);
+  let Inst{12-6}  = !if(ps.has_sdst, sdst{6-0}, ?);
 }
 
-class SMEM_Real_Prefetch_gfx12 <bits<8> op, SM_Pseudo ps> : SMEM_Real_gfx12<op, ps> {
+class SMEM_Real_Prefetch_gfx12<bits<6> op, SM_Pseudo ps> :
+    SMEM_Real_gfx12<op, ps> {
   bits<7> sdata; // Only 5 bits of sdata are supported.
 
   let sdst = ?;
   let Inst{12-11} = 0; // Unused sdata bits.
   let Inst{10-6}  = !if(ps.has_sdst, sdata{4-0}, ?);
 }
 
+class SMEM_Real_Load_gfx12<bits<6> op, string ps, string opName, OffsetMode offsets> :
+    SMEM_Real_gfx12<op, !cast<SM_Pseudo>(ps # offsets.Variant), opName> {
+  RegisterClass BaseClass = !cast<SM_Load_Pseudo>(ps # offsets.Variant).BaseClass;
+  let InOperandList = !con((ins BaseClass:$sbase), offsets.Ins, (ins CPol:$cpol));
+
+  let Inst{22-21} = cpol{4-3}; // scope
+  let Inst{24-23} = cpol{1-0}; // th - only lower 2 bits are supported
+}
+
+multiclass SM_Real_Loads_gfx12<bits<6> op, string ps = NAME> {
+  defvar opName = !tolower(NAME);
+  def _IMM_gfx12 : SMEM_Real_Load_gfx12<op, ps, opName, IMM_Offset>;
+  def _SGPR_IMM_gfx12 : SMEM_Real_Load_gfx12<op, ps, opName, SGPR_IMM_Offset>;
+}
+
+defm S_LOAD_B32  : SM_Real_Loads_gfx12<0x00, "S_LOAD_DWORD">;
+defm S_LOAD_B64  : SM_Real_Loads_gfx12<0x01, "S_LOAD_DWORDX2">;
+defm S_LOAD_B96  : SM_Real_Loads_gfx12<0x05, "S_LOAD_DWORDX3">;
+defm S_LOAD_B128 : SM_Real_Loads_gfx12<0x02, "S_LOAD_DWORDX4">;
+defm S_LOAD_B256 : SM_Real_Loads_gfx12<0x03, "S_LOAD_DWORDX8">;
+defm S_LOAD_B512 : SM_Real_Loads_gfx12<0x04, "S_LOAD_DWORDX16">;
+
+defm S_BUFFER_LOAD_B32  : SM_Real_Loads_gfx12<0x10, "S_BUFFER_LOAD_DWORD">;
+defm S_BUFFER_LOAD_B64  : SM_Real_Loads_gfx12<0x11, "S_BUFFER_LOAD_DWORDX2">;
+defm S_BUFFER_LOAD_B96  : SM_Real_Loads_gfx12<0x15, "S_BUFFER_LOAD_DWORDX3">;
+defm S_BUFFER_LOAD_B128 : SM_Real_Loads_gfx12<0x12, "S_BUFFER_LOAD_DWORDX4">;
+defm S_BUFFER_LOAD_B256 : SM_Real_Loads_gfx12<0x13, "S_BUFFER_LOAD_DWORDX8">;
+defm S_BUFFER_LOAD_B512 : SM_Real_Loads_gfx12<0x14, "S_BUFFER_LOAD_DWORDX16">;
+
+def S_DCACHE_INV_gfx12 : SMEM_Real_gfx12<0x021, S_DCACHE_INV>;
+
 def S_PREFETCH_INST_gfx12        : SMEM_Real_Prefetch_gfx12<0x24, S_PREFETCH_INST>;
 def S_PREFETCH_INST_PC_REL_gfx12 : SMEM_Real_Prefetch_gfx12<0x25, S_PREFETCH_INST_PC_REL>;
 def S_PREFETCH_DATA_gfx12        : SMEM_Real_Prefetch_gfx12<0x26, S_PREFETCH_DATA>;
 def S_BUFFER_PREFETCH_DATA_gfx12 : SMEM_Real_Prefetch_gfx12<0x27, S_BUFFER_PREFETCH_DATA>;
 def S_PREFETCH_DATA_PC_REL_gfx12 : SMEM_Real_Prefetch_gfx12<0x28, S_PREFETCH_DATA_PC_REL>;
+
+multiclass SMEM_Real_Probe_gfx12<bits<6> op> {
+  defvar ps = NAME;
+  def _IMM_gfx12      : SMEM_Real_Prefetch_gfx12<op, !cast<SM_Probe_Pseudo>(ps#_IMM)>;
+  def _SGPR_IMM_gfx12 : SMEM_Real_Prefetch_gfx12<op, !cast<SM_Probe_Pseudo>(ps#_SGPR_IMM)>;
+}
+
+defm S_ATC_PROBE        : SMEM_Real_Probe_gfx12<0x22>;
+defm S_ATC_PROBE_BUFFER : SMEM_Real_Probe_gfx12<0x23>;

llvm/test/MC/AMDGPU/gfx11_asm_err.s

@@ -158,3 +158,9 @@ scratch_store_b128 off, v[2:5], s0 offset:8000000
 
 flat_atomic_add_f32 v1, v[0:1], v2 offset:-1
 // GFX11: :[[@LINE-1]]:{{[0-9]+}}: error: expected a 12-bit unsigned offset
+
+s_load_b96 s[20:22], s[2:3], s0
+// GFX11: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU
+
+s_buffer_load_b96 s[20:22], s[4:7], s0
+// GFX11: :[[@LINE-1]]:{{[0-9]+}}: error: instruction not supported on this GPU