[clang] [llvm] [WIP][LLVM] Add `__builtin_readfixedtimer` intrinsic and buiiltin (PR #81331)
Joseph Huber via llvm-commits
llvm-commits at lists.llvm.org
Fri Feb 9 14:52:19 PST 2024
https://github.com/jhuber6 created https://github.com/llvm/llvm-project/pull/81331
Summary:
This patch adds a new intrinsic and builtin function mirroring the
existing `__builtin_readcyclecounter`. The difference is that this
implementation targets a separate counter that some targets have which
returns a fixed frequency clock that can be used to determine elapsed
time, this is different compared to the cycle counter which often has
variable frequency. This is currently only valid for the NVPTX and
AMDGPU targets.
>From f6d905fe46c18b8076bb9af4ccb6583ed60d5ca6 Mon Sep 17 00:00:00 2001
From: Joseph Huber <huberjn at outlook.com>
Date: Fri, 9 Feb 2024 16:13:42 -0600
Subject: [PATCH] [WIP][LLVM] Add `__builtin_readfixedtimer` intrinsic and
buiiltin
Summary:
This patch adds a new intrinsic and builtin function mirroring the
existing `__builtin_readcyclecounter`. The difference is that this
implementation targets a separate counter that some targets have which
returns a fixed frequency clock that can be used to determine elapsed
time, this is different compared to the cycle counter which often has
variable frequency. This is currently only valid for the NVPTX and
AMDGPU targets.
---
clang/include/clang/Basic/Builtins.td | 6 ++++++
clang/lib/CodeGen/CGBuiltin.cpp | 4 ++++
llvm/include/llvm/CodeGen/ISDOpcodes.h | 6 ++++++
llvm/include/llvm/IR/Intrinsics.td | 2 ++
llvm/include/llvm/Support/TargetOpcodes.def | 3 +++
llvm/include/llvm/Target/GenericOpcodes.td | 6 ++++++
.../llvm/Target/GlobalISel/SelectionDAGCompat.td | 1 +
llvm/include/llvm/Target/TargetSelectionDAG.td | 3 +++
llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp | 2 ++
llvm/lib/CodeGen/IntrinsicLowering.cpp | 6 ++++++
llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp | 6 ++++--
.../CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp | 5 +++--
llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h | 2 +-
.../CodeGen/SelectionDAG/SelectionDAGBuilder.cpp | 8 ++++++++
.../CodeGen/SelectionDAG/SelectionDAGDumper.cpp | 1 +
llvm/lib/CodeGen/TargetLoweringBase.cpp | 3 +++
llvm/lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp | 3 +++
llvm/lib/Target/AMDGPU/AMDGPURegisterBankInfo.cpp | 1 +
llvm/lib/Target/AMDGPU/SMInstructions.td | 14 ++++++++++++++
19 files changed, 77 insertions(+), 5 deletions(-)
diff --git a/clang/include/clang/Basic/Builtins.td b/clang/include/clang/Basic/Builtins.td
index 31a2bdeb2d3e5e..3bc043b35e187b 100644
--- a/clang/include/clang/Basic/Builtins.td
+++ b/clang/include/clang/Basic/Builtins.td
@@ -1110,6 +1110,12 @@ def ReadCycleCounter : Builtin {
let Prototype = "unsigned long long int()";
}
+def ReadFixedTimer : Builtin {
+ let Spellings = ["__builtin_readfixedtimer"];
+ let Attributes = [NoThrow];
+ let Prototype = "unsigned long long int()";
+}
+
def Trap : Builtin {
let Spellings = ["__builtin_trap"];
let Attributes = [NoThrow, NoReturn];
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index a7a410dab1a018..8da8bbc56758d5 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -3443,6 +3443,10 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
Function *F = CGM.getIntrinsic(Intrinsic::readcyclecounter);
return RValue::get(Builder.CreateCall(F));
}
+ case Builtin::BI__builtin_readfixedtimer: {
+ Function *F = CGM.getIntrinsic(Intrinsic::readfixedtimer);
+ return RValue::get(Builder.CreateCall(F));
+ }
case Builtin::BI__builtin___clear_cache: {
Value *Begin = EmitScalarExpr(E->getArg(0));
Value *End = EmitScalarExpr(E->getArg(1));
diff --git a/llvm/include/llvm/CodeGen/ISDOpcodes.h b/llvm/include/llvm/CodeGen/ISDOpcodes.h
index 349d1286c8dc4f..882e80c521e897 100644
--- a/llvm/include/llvm/CodeGen/ISDOpcodes.h
+++ b/llvm/include/llvm/CodeGen/ISDOpcodes.h
@@ -1179,6 +1179,12 @@ enum NodeType {
/// counter-like register (or other high accuracy low latency clock source).
READCYCLECOUNTER,
+ /// READFIXEDTIMER - This corresponds to the readfixedcounter intrinsic.
+ /// It has the same semantics as the READCYCLECOUNTER implementation except
+ /// that the result is the content of the architecture-specific fixed
+ /// frequency counter suitable for measuring elapsed time.
+ READFIXEDTIMER,
+
/// HANDLENODE node - Used as a handle for various purposes.
HANDLENODE,
diff --git a/llvm/include/llvm/IR/Intrinsics.td b/llvm/include/llvm/IR/Intrinsics.td
index 3c19c7b063652c..4d7c57944f3778 100644
--- a/llvm/include/llvm/IR/Intrinsics.td
+++ b/llvm/include/llvm/IR/Intrinsics.td
@@ -870,6 +870,8 @@ def int_pcmarker : DefaultAttrsIntrinsic<[], [llvm_i32_ty]>;
def int_readcyclecounter : DefaultAttrsIntrinsic<[llvm_i64_ty]>;
+def int_readfixedtimer : DefaultAttrsIntrinsic<[llvm_i64_ty]>;
+
// The assume intrinsic is marked InaccessibleMemOnly so that proper control
// dependencies will be maintained.
def int_assume : DefaultAttrsIntrinsic<
diff --git a/llvm/include/llvm/Support/TargetOpcodes.def b/llvm/include/llvm/Support/TargetOpcodes.def
index abb237083d254e..29c6b6488ebb72 100644
--- a/llvm/include/llvm/Support/TargetOpcodes.def
+++ b/llvm/include/llvm/Support/TargetOpcodes.def
@@ -352,6 +352,9 @@ HANDLE_TARGET_OPCODE(G_INTRINSIC_ROUNDEVEN)
/// INTRINSIC readcyclecounter
HANDLE_TARGET_OPCODE(G_READCYCLECOUNTER)
+/// INTRINSIC readfixedtimer
+HANDLE_TARGET_OPCODE(G_READFIXEDTIMER)
+
/// Generic load (including anyext load)
HANDLE_TARGET_OPCODE(G_LOAD)
diff --git a/llvm/include/llvm/Target/GenericOpcodes.td b/llvm/include/llvm/Target/GenericOpcodes.td
index 2c73b67f9e1af0..1b3f84c1d782bf 100644
--- a/llvm/include/llvm/Target/GenericOpcodes.td
+++ b/llvm/include/llvm/Target/GenericOpcodes.td
@@ -1101,6 +1101,12 @@ def G_READCYCLECOUNTER : GenericInstruction {
let hasSideEffects = true;
}
+def G_READFIXEDTIMER : GenericInstruction {
+ let OutOperandList = (outs type0:$dst);
+ let InOperandList = (ins);
+ let hasSideEffects = true;
+}
+
//------------------------------------------------------------------------------
// Memory ops
//------------------------------------------------------------------------------
diff --git a/llvm/include/llvm/Target/GlobalISel/SelectionDAGCompat.td b/llvm/include/llvm/Target/GlobalISel/SelectionDAGCompat.td
index f792237203b431..e3e9622ae919d9 100644
--- a/llvm/include/llvm/Target/GlobalISel/SelectionDAGCompat.td
+++ b/llvm/include/llvm/Target/GlobalISel/SelectionDAGCompat.td
@@ -167,6 +167,7 @@ def : GINodeEquiv<G_FMAXNUM_IEEE, fmaxnum_ieee>;
def : GINodeEquiv<G_FMAXIMUM, fmaximum>;
def : GINodeEquiv<G_FMINIMUM, fminimum>;
def : GINodeEquiv<G_READCYCLECOUNTER, readcyclecounter>;
+def : GINodeEquiv<G_READFIXEDTIMER, readfixedtimer>;
def : GINodeEquiv<G_ROTR, rotr>;
def : GINodeEquiv<G_ROTL, rotl>;
def : GINodeEquiv<G_LROUND, lround>;
diff --git a/llvm/include/llvm/Target/TargetSelectionDAG.td b/llvm/include/llvm/Target/TargetSelectionDAG.td
index 22360353790dbc..bedfa6807f425a 100644
--- a/llvm/include/llvm/Target/TargetSelectionDAG.td
+++ b/llvm/include/llvm/Target/TargetSelectionDAG.td
@@ -657,6 +657,9 @@ def prefetch : SDNode<"ISD::PREFETCH" , SDTPrefetch,
def readcyclecounter : SDNode<"ISD::READCYCLECOUNTER", SDTIntLeaf,
[SDNPHasChain, SDNPSideEffect]>;
+def readfixedtimer : SDNode<"ISD::READFIXEDTIMER", SDTIntLeaf,
+ [SDNPHasChain, SDNPSideEffect]>;
+
def membarrier : SDNode<"ISD::MEMBARRIER", SDTNone,
[SDNPHasChain, SDNPSideEffect]>;
diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
index c1d8e890a66edb..2b2d03ab69c01c 100644
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -1885,6 +1885,8 @@ unsigned IRTranslator::getSimpleIntrinsicOpcode(Intrinsic::ID ID) {
return TargetOpcode::G_INTRINSIC_TRUNC;
case Intrinsic::readcyclecounter:
return TargetOpcode::G_READCYCLECOUNTER;
+ case Intrinsic::readfixedtimer:
+ return TargetOpcode::G_READFIXEDTIMER;
case Intrinsic::ptrmask:
return TargetOpcode::G_PTRMASK;
case Intrinsic::lrint:
diff --git a/llvm/lib/CodeGen/IntrinsicLowering.cpp b/llvm/lib/CodeGen/IntrinsicLowering.cpp
index 61920a0e04ab59..106799bc306850 100644
--- a/llvm/lib/CodeGen/IntrinsicLowering.cpp
+++ b/llvm/lib/CodeGen/IntrinsicLowering.cpp
@@ -312,6 +312,12 @@ void IntrinsicLowering::LowerIntrinsicCall(CallInst *CI) {
CI->replaceAllUsesWith(ConstantInt::get(Type::getInt64Ty(Context), 0));
break;
}
+ case Intrinsic::readfixedtimer: {
+ errs() << "WARNING: this target does not support the llvm.readfixedtimer"
+ << " intrinsic. It is being lowered to a constant 0\n";
+ CI->replaceAllUsesWith(ConstantInt::get(Type::getInt64Ty(Context), 0));
+ break;
+ }
case Intrinsic::dbg_declare:
case Intrinsic::dbg_label:
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 892bfbd62f0d02..29c2356cdc438c 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -1127,8 +1127,9 @@ void SelectionDAGLegalize::LegalizeOp(SDNode *Node) {
Action = TargetLowering::Custom;
break;
case ISD::READCYCLECOUNTER:
- // READCYCLECOUNTER returns an i64, even if type legalization might have
- // expanded that to several smaller types.
+ case ISD::READFIXEDTIMER:
+ // READCYCLECOUNTER and READFIXEDTIMER return a i64, even if type
+ // legalization might have expanded that to several smaller types.
Action = TLI.getOperationAction(Node->getOpcode(), MVT::i64);
break;
case ISD::READ_REGISTER:
@@ -3080,6 +3081,7 @@ bool SelectionDAGLegalize::ExpandNode(SDNode *Node) {
Results.push_back(Node->getOperand(0));
break;
case ISD::READCYCLECOUNTER:
+ case ISD::READFIXEDTIMER:
// If the target didn't expand this, just return 'zero' and preserve the
// chain.
Results.append(Node->getNumValues() - 1,
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
index 39b7e061554141..cd0e910752d6b2 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -2648,7 +2648,8 @@ void DAGTypeLegalizer::ExpandIntegerResult(SDNode *N, unsigned ResNo) {
case ISD::LLRINT: ExpandIntRes_XROUND_XRINT(N, Lo, Hi); break;
case ISD::LOAD: ExpandIntRes_LOAD(cast<LoadSDNode>(N), Lo, Hi); break;
case ISD::MUL: ExpandIntRes_MUL(N, Lo, Hi); break;
- case ISD::READCYCLECOUNTER: ExpandIntRes_READCYCLECOUNTER(N, Lo, Hi); break;
+ case ISD::READCYCLECOUNTER: ExpandIntRes_READCOUNTER(N, Lo, Hi); break;
+ case ISD::READFIXEDTIMER: ExpandIntRes_READCOUNTER(N, Lo, Hi); break;
case ISD::SDIV: ExpandIntRes_SDIV(N, Lo, Hi); break;
case ISD::SIGN_EXTEND: ExpandIntRes_SIGN_EXTEND(N, Lo, Hi); break;
case ISD::SIGN_EXTEND_INREG: ExpandIntRes_SIGN_EXTEND_INREG(N, Lo, Hi); break;
@@ -4026,7 +4027,7 @@ void DAGTypeLegalizer::ExpandIntRes_MUL(SDNode *N,
Lo, Hi);
}
-void DAGTypeLegalizer::ExpandIntRes_READCYCLECOUNTER(SDNode *N, SDValue &Lo,
+void DAGTypeLegalizer::ExpandIntRes_READCOUNTER(SDNode *N, SDValue &Lo,
SDValue &Hi) {
SDLoc DL(N);
EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), N->getValueType(0));
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
index 09f0bca8b8611e..91149871628574 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -439,7 +439,7 @@ class LLVM_LIBRARY_VISIBILITY DAGTypeLegalizer {
void ExpandIntRes_CTPOP (SDNode *N, SDValue &Lo, SDValue &Hi);
void ExpandIntRes_CTTZ (SDNode *N, SDValue &Lo, SDValue &Hi);
void ExpandIntRes_LOAD (LoadSDNode *N, SDValue &Lo, SDValue &Hi);
- void ExpandIntRes_READCYCLECOUNTER (SDNode *N, SDValue &Lo, SDValue &Hi);
+ void ExpandIntRes_READCOUNTER (SDNode *N, SDValue &Lo, SDValue &Hi);
void ExpandIntRes_SIGN_EXTEND (SDNode *N, SDValue &Lo, SDValue &Hi);
void ExpandIntRes_SIGN_EXTEND_INREG (SDNode *N, SDValue &Lo, SDValue &Hi);
void ExpandIntRes_TRUNCATE (SDNode *N, SDValue &Lo, SDValue &Hi);
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 5ce1013f30fd1b..ee1164c48140b3 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -6781,6 +6781,14 @@ void SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I,
DAG.setRoot(Res.getValue(1));
return;
}
+ case Intrinsic::readfixedtimer: {
+ SDValue Op = getRoot();
+ Res = DAG.getNode(ISD::READFIXEDTIMER, sdl,
+ DAG.getVTList(MVT::i64, MVT::Other), Op);
+ setValue(&I, Res);
+ DAG.setRoot(Res.getValue(1));
+ return;
+ }
case Intrinsic::bitreverse:
setValue(&I, DAG.getNode(ISD::BITREVERSE, sdl,
getValue(I.getArgOperand(0)).getValueType(),
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
index a28d834f0522f2..0d308fa8ad16be 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
@@ -104,6 +104,7 @@ std::string SDNode::getOperationName(const SelectionDAG *G) const {
case ISD::ATOMIC_STORE: return "AtomicStore";
case ISD::PCMARKER: return "PCMarker";
case ISD::READCYCLECOUNTER: return "ReadCycleCounter";
+ case ISD::READFIXEDTIMER: return "ReadFixedTimer";
case ISD::SRCVALUE: return "SrcValue";
case ISD::MDNODE_SDNODE: return "MDNode";
case ISD::EntryToken: return "EntryToken";
diff --git a/llvm/lib/CodeGen/TargetLoweringBase.cpp b/llvm/lib/CodeGen/TargetLoweringBase.cpp
index d8302ba2b42608..e06b266ba3cc1d 100644
--- a/llvm/lib/CodeGen/TargetLoweringBase.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringBase.cpp
@@ -964,6 +964,9 @@ void TargetLoweringBase::initActions() {
// Most targets also ignore the @llvm.readcyclecounter intrinsic.
setOperationAction(ISD::READCYCLECOUNTER, MVT::i64, Expand);
+ // Most targets also ignore the @llvm.readfixedtimer intrinsic.
+ setOperationAction(ISD::READFIXEDTIMER, MVT::i64, Expand);
+
// ConstantFP nodes default to expand. Targets can either change this to
// Legal, in which case all fp constants are legal, or use isFPImmLegal()
// to optimize expansions for certain constants.
diff --git a/llvm/lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp b/llvm/lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp
index 97952de3e6a37b..c9ea359d79e394 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp
@@ -1957,6 +1957,9 @@ AMDGPULegalizerInfo::AMDGPULegalizerInfo(const GCNSubtarget &ST_,
getActionDefinitionsBuilder(G_READCYCLECOUNTER)
.legalFor({S64});
+ getActionDefinitionsBuilder(G_READFIXEDTIMER)
+ .legalFor({S64});
+
getActionDefinitionsBuilder(G_FENCE)
.alwaysLegal();
diff --git a/llvm/lib/Target/AMDGPU/AMDGPURegisterBankInfo.cpp b/llvm/lib/Target/AMDGPU/AMDGPURegisterBankInfo.cpp
index 5323e4fc58de80..4a2c2ecdd8dd8b 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPURegisterBankInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPURegisterBankInfo.cpp
@@ -4051,6 +4051,7 @@ AMDGPURegisterBankInfo::getInstrMapping(const MachineInstr &MI) const {
case AMDGPU::G_CONSTANT:
case AMDGPU::G_GLOBAL_VALUE:
case AMDGPU::G_BLOCK_ADDR:
+ case AMDGPU::G_READFIXEDTIMER:
case AMDGPU::G_READCYCLECOUNTER: {
unsigned Size = MRI.getType(MI.getOperand(0).getReg()).getSizeInBits();
OpdsMapping[0] = AMDGPU::getValueMapping(AMDGPU::SGPRRegBankID, Size);
diff --git a/llvm/lib/Target/AMDGPU/SMInstructions.td b/llvm/lib/Target/AMDGPU/SMInstructions.td
index f3096962e2f3e8..21ef528bed2f8f 100644
--- a/llvm/lib/Target/AMDGPU/SMInstructions.td
+++ b/llvm/lib/Target/AMDGPU/SMInstructions.td
@@ -1068,6 +1068,20 @@ def : GCNPat <
}
} // let OtherPredicates = [HasShaderCyclesRegister]
+let OtherPredicates = [HasSMemRealTime] in {
+def : GCNPat <
+ (i64 (readfixedtimer)),
+ (S_MEMREALTIME)
+>;
+} // let OtherPredicates = [HasSMemRealTime]
+
+let SubtargetPredicate = isGFX11Plus in {
+def : GCNPat <
+ (i64 (readfixedtimer)),
+ (S_SENDMSG_RTN_B64 (i32 0x83))
+>;
+} // let SubtargetPredicate = [isGFX11Plus]
+
def i32imm_zero : TImmLeaf <i32, [{
return Imm == 0;
}]>;
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