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[AMDGPU][AsmParser] Allow v_writelane_b32 to use SGPR and M0 as source operands at the same time #78827

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Merged
merged 1 commit into from
Jan 30, 2024
Merged

[AMDGPU][AsmParser] Allow v_writelane_b32 to use SGPR and M0 as source operands at the same time #78827

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21 changes: 21 additions & 0 deletions llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3514,6 +3514,24 @@ bool AMDGPUAsmParser::usesConstantBus(const MCInst &Inst, unsigned OpIdx) {
}
}

// Based on the comment for `AMDGPUInstructionSelector::selectWritelane`:
// Writelane is special in that it can use SGPR and M0 (which would normally
// count as using the constant bus twice - but in this case it is allowed since
// the lane selector doesn't count as a use of the constant bus). However, it is
// still required to abide by the 1 SGPR rule.
static bool checkWriteLane(const MCInst &Inst) {
const unsigned Opcode = Inst.getOpcode();
if (Opcode != V_WRITELANE_B32_gfx6_gfx7 && Opcode != V_WRITELANE_B32_vi)
return false;
const MCOperand &LaneSelOp = Inst.getOperand(2);
if (!LaneSelOp.isReg())
return false;
auto LaneSelReg = mc2PseudoReg(LaneSelOp.getReg());
if (LaneSelReg == M0 || LaneSelReg == M0_gfxpre11)
return true;
return false;
}

bool AMDGPUAsmParser::validateConstantBusLimitations(
const MCInst &Inst, const OperandVector &Operands) {
const unsigned Opcode = Inst.getOpcode();
Expand All @@ -3529,6 +3547,9 @@ bool AMDGPUAsmParser::validateConstantBusLimitations(
!isVOPD(Opcode))
return true;

if (checkWriteLane(Inst))
return true;

// Check special imm operands (used by madmk, etc)
if (AMDGPU::hasNamedOperand(Opcode, AMDGPU::OpName::imm)) {
++NumLiterals;
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18 changes: 18 additions & 0 deletions llvm/test/MC/AMDGPU/writelane_m0.s
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@@ -0,0 +1,18 @@
// RUN: llvm-mc --triple=amdgcn --mcpu=gfx600 -show-encoding %s | FileCheck %s -check-prefix=GFX6
// RUN: llvm-mc --triple=amdgcn --mcpu=gfx700 -show-encoding %s | FileCheck %s -check-prefix=GFX7
// RUN: llvm-mc --triple=amdgcn --mcpu=gfx904 -show-encoding %s | FileCheck %s -check-prefix=GFX9
// RUN: llvm-mc --triple=amdgcn --mcpu=gfx940 -show-encoding %s | FileCheck %s -check-prefix=GFX9
// RUN: llvm-mc --triple=amdgcn --mcpu=gfx1010 -show-encoding %s | FileCheck %s -check-prefix=GFX10
// RUN: llvm-mc --triple=amdgcn --mcpu=gfx1030 -show-encoding %s | FileCheck %s -check-prefix=GFX10
// RUN: llvm-mc --triple=amdgcn --mcpu=gfx1100 -show-encoding %s | FileCheck %s -check-prefix=GFX11
// RUN: llvm-mc --triple=amdgcn --mcpu=gfx1200 -show-encoding %s | FileCheck %s -check-prefix=GFX12

.text
v_writelane_b32 v1, s13, m0

// GFX6: v_writelane_b32 v1, s13, m0 ; encoding: [0x0d,0xf8,0x02,0x04]
// GFX7: v_writelane_b32 v1, s13, m0 ; encoding: [0x0d,0xf8,0x02,0x04]
// GFX9: v_writelane_b32 v1, s13, m0 ; encoding: [0x01,0x00,0x8a,0xd2,0x0d,0xf8,0x00,0x00]
// GFX10: v_writelane_b32 v1, s13, m0 ; encoding: [0x01,0x00,0x61,0xd7,0x0d,0xf8,0x00,0x00]
// GFX11: v_writelane_b32 v1, s13, m0 ; encoding: [0x01,0x00,0x61,0xd7,0x0d,0xfa,0x00,0x00]
// GFX12: v_writelane_b32 v1, s13, m0 ; encoding: [0x01,0x00,0x61,0xd7,0x0d,0xfa,0x00,0x00]
16 changes: 16 additions & 0 deletions llvm/test/MachineVerifier/writelane_m0.mir
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@@ -0,0 +1,16 @@
# RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx600 -verify-machineinstrs -run-pass=none -o - %s | FileCheck %s
# RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx700 -verify-machineinstrs -run-pass=none -o - %s | FileCheck %s
# RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx904 -verify-machineinstrs -run-pass=none -o - %s | FileCheck %s
# RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx940 -verify-machineinstrs -run-pass=none -o - %s | FileCheck %s
# RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx1010 -verify-machineinstrs -run-pass=none -o - %s | FileCheck %s
# RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx1030 -verify-machineinstrs -run-pass=none -o - %s | FileCheck %s
# RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx1100 -verify-machineinstrs -run-pass=none -o - %s | FileCheck %s
# RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx1200 -verify-machineinstrs -run-pass=none -o - %s | FileCheck %s

---

name: writelane_m0
body: |
bb.0:
; CHECK: $vgpr0 = V_WRITELANE_B32 $sgpr0, $m0, $vgpr0
$vgpr0 = V_WRITELANE_B32 $sgpr0, $m0, $vgpr0