[llvm] [AMDGPU] Add subtarget feature for v_lshl_add_u64. NFC. (PR #133723)

[Jay Foad via llvm-commits]

https://github.com/jayfoad created https://github.com/llvm/llvm-project/pull/133723

None

>From c4f3443c5e8e11f136cdb4ef3bbf375d0e07aa35 Mon Sep 17 00:00:00 2001
From: Jay Foad <jay.foad at amd.com>
Date: Mon, 31 Mar 2025 14:59:17 +0100
Subject: [PATCH] [AMDGPU] Add subtarget feature for v_lshl_add_u64. NFC.

---
 llvm/lib/Target/AMDGPU/AMDGPU.td           | 10 +++++++++-
 llvm/lib/Target/AMDGPU/GCNSubtarget.h      |  3 ++-
 llvm/lib/Target/AMDGPU/SIISelLowering.cpp  |  2 +-
 llvm/lib/Target/AMDGPU/VOP3Instructions.td |  2 +-
 4 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/llvm/lib/Target/AMDGPU/AMDGPU.td b/llvm/lib/Target/AMDGPU/AMDGPU.td
index 84619dd656f35..72b4aca6f543a 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPU.td
+++ b/llvm/lib/Target/AMDGPU/AMDGPU.td
@@ -1269,6 +1269,10 @@ def FeatureDynamicVGPRBlockSize32 : SubtargetFeature<"dynamic-vgpr-block-size-32
   "Use a block size of 32 for dynamic VGPR allocation (default is 16)"
 >;
 
+def FeatureLshlAddU64
+    : SubtargetFeature<"lshl-add-u64", "HasLshlAddU64", "true",
+                       "Has v_lshl_add_u64 instruction">;
+
 // Dummy feature used to disable assembler instructions.
 def FeatureDisable : SubtargetFeature<"",
   "FeatureDisable","true",
@@ -1622,7 +1626,8 @@ def FeatureISAVersion9_4_Common : FeatureSet<
    FeatureAtomicFMinFMaxF64FlatInsts,
    FeatureAgentScopeFineGrainedRemoteMemoryAtomics,
    FeatureMemoryAtomicFAddF32DenormalSupport,
-   FeatureFlatBufferGlobalAtomicFaddF64Inst
+   FeatureFlatBufferGlobalAtomicFaddF64Inst,
+   FeatureLshlAddU64,
    ]>;
 
 def FeatureISAVersion9_5_Common : FeatureSet<
@@ -2554,6 +2559,9 @@ def HasXF32Insts : Predicate<"Subtarget->hasXF32Insts()">,
 def HasAshrPkInsts : Predicate<"Subtarget->hasAshrPkInsts()">,
   AssemblerPredicate<(all_of FeatureAshrPkInsts)>;
 
+def HasLshlAddU64 : Predicate<"Subtarget->hasLshlAddU64()">,
+  AssemblerPredicate<(all_of FeatureLshlAddU64)>;
+
 // Include AMDGPU TD files
 include "SISchedule.td"
 include "GCNProcessors.td"
diff --git a/llvm/lib/Target/AMDGPU/GCNSubtarget.h b/llvm/lib/Target/AMDGPU/GCNSubtarget.h
index 7384278d81cc1..d5ab02da87e1e 100644
--- a/llvm/lib/Target/AMDGPU/GCNSubtarget.h
+++ b/llvm/lib/Target/AMDGPU/GCNSubtarget.h
@@ -257,6 +257,7 @@ class GCNSubtarget final : public AMDGPUGenSubtargetInfo,
   bool HasMinimum3Maximum3F32 = false;
   bool HasMinimum3Maximum3F16 = false;
   bool HasMinimum3Maximum3PKF16 = false;
+  bool HasLshlAddU64 = false;
 
   bool RequiresCOV6 = false;
 
@@ -1140,7 +1141,7 @@ class GCNSubtarget final : public AMDGPUGenSubtargetInfo,
 
   bool hasMovB64() const { return GFX940Insts; }
 
-  bool hasLshlAddB64() const { return GFX940Insts; }
+  bool hasLshlAddU64() const { return HasLshlAddU64; }
 
   bool enableSIScheduler() const {
     return EnableSIScheduler;
diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
index c8645850fe111..bc9add218520a 100644
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -5246,7 +5246,7 @@ SITargetLowering::EmitInstrWithCustomInserter(MachineInstr &MI,
     MachineOperand &Src0 = MI.getOperand(1);
     MachineOperand &Src1 = MI.getOperand(2);
 
-    if (IsAdd && ST.hasLshlAddB64()) {
+    if (IsAdd && ST.hasLshlAddU64()) {
       auto Add = BuildMI(*BB, MI, DL, TII->get(AMDGPU::V_LSHL_ADD_U64_e64),
                          Dest.getReg())
                      .add(Src0)
diff --git a/llvm/lib/Target/AMDGPU/VOP3Instructions.td b/llvm/lib/Target/AMDGPU/VOP3Instructions.td
index 14da3447a2256..cc33a9622e62f 100644
--- a/llvm/lib/Target/AMDGPU/VOP3Instructions.td
+++ b/llvm/lib/Target/AMDGPU/VOP3Instructions.td
@@ -679,7 +679,7 @@ defm V_LSHL_OR_B32 : VOP3Inst <"v_lshl_or_b32", VOP3_Profile<VOP_I32_I32_I32_I32
 
 // V_LSHL_ADD_U64: D0.u64 = (S0.u64 << S1.u[2:0]) + S2.u64
 // src0 is shifted left by 0-4 (use “0” to get ADD_U64).
-let SubtargetPredicate = isGFX940Plus in
+let SubtargetPredicate = HasLshlAddU64 in
 defm V_LSHL_ADD_U64 : VOP3Inst <"v_lshl_add_u64", VOP3_Profile<VOP_I64_I64_I32_I64>>;
 
 let OtherPredicates = [HasFP8ConversionInsts], mayRaiseFPException = 0,