[llvm] DAG: Avoid some libcall string name comparisons (PR #166321)
Matt Arsenault via llvm-commits
llvm-commits at lists.llvm.org
Tue Nov 4 11:00:30 PST 2025
https://github.com/arsenm updated https://github.com/llvm/llvm-project/pull/166321
>From b648a8c810d3424d8de51f25b31b65073dcd8eae Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Mon, 3 Nov 2025 22:51:10 -0800
Subject: [PATCH 1/3] DAG: Avoid some libcall string name comparisons
Move to the libcall impl based functions.
---
.../lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 31 +++++++++++--------
1 file changed, 18 insertions(+), 13 deletions(-)
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 379242ec5a157..3365c507b8f03 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -9257,21 +9257,22 @@ SDValue SelectionDAG::getMemcpy(
// FIXME: pass in SDLoc
TargetLowering::CallLoweringInfo CLI(*this);
bool IsTailCall = false;
- const char *MemCpyName = TLI->getMemcpyName();
+ RTLIB::LibcallImpl MemCpyImpl = TLI->getLibcallImpl(RTLIB::MEMCPY);
if (OverrideTailCall.has_value()) {
IsTailCall = *OverrideTailCall;
} else {
- bool LowersToMemcpy = StringRef(MemCpyName) == StringRef("memcpy");
+ bool LowersToMemcpy = MemCpyImpl == RTLIB::impl_memcpy;
IsTailCall = isInTailCallPositionWrapper(CI, this, LowersToMemcpy);
}
CLI.setDebugLoc(dl)
.setChain(Chain)
.setLibCallee(
- TLI->getLibcallCallingConv(RTLIB::MEMCPY),
+ TLI->getLibcallImplCallingConv(MemCpyImpl),
Dst.getValueType().getTypeForEVT(*getContext()),
- getExternalSymbol(MemCpyName, TLI->getPointerTy(getDataLayout())),
+ getExternalSymbol(TLI->getLibcallImplName(MemCpyImpl).data(),
+ TLI->getPointerTy(getDataLayout())),
std::move(Args))
.setDiscardResult()
.setTailCall(IsTailCall);
@@ -9361,22 +9362,24 @@ SDValue SelectionDAG::getMemmove(SDValue Chain, const SDLoc &dl, SDValue Dst,
// FIXME: pass in SDLoc
TargetLowering::CallLoweringInfo CLI(*this);
+ RTLIB::LibcallImpl MemmoveImpl = TLI->getLibcallImpl(RTLIB::MEMMOVE);
+
bool IsTailCall = false;
if (OverrideTailCall.has_value()) {
IsTailCall = *OverrideTailCall;
} else {
- bool LowersToMemmove =
- TLI->getLibcallName(RTLIB::MEMMOVE) == StringRef("memmove");
+ bool LowersToMemmove = MemmoveImpl == RTLIB::impl_memmove;
IsTailCall = isInTailCallPositionWrapper(CI, this, LowersToMemmove);
}
CLI.setDebugLoc(dl)
.setChain(Chain)
- .setLibCallee(TLI->getLibcallCallingConv(RTLIB::MEMMOVE),
- Dst.getValueType().getTypeForEVT(*getContext()),
- getExternalSymbol(TLI->getLibcallName(RTLIB::MEMMOVE),
- TLI->getPointerTy(getDataLayout())),
- std::move(Args))
+ .setLibCallee(
+ TLI->getLibcallImplCallingConv(MemmoveImpl),
+ Dst.getValueType().getTypeForEVT(*getContext()),
+ getExternalSymbol(TLI->getLibcallImplName(MemmoveImpl).data(),
+ TLI->getPointerTy(getDataLayout())),
+ std::move(Args))
.setDiscardResult()
.setTailCall(IsTailCall);
@@ -9492,8 +9495,10 @@ SDValue SelectionDAG::getMemset(SDValue Chain, const SDLoc &dl, SDValue Dst,
TLI->getPointerTy(DL)),
std::move(Args));
}
- bool LowersToMemset =
- TLI->getLibcallName(RTLIB::MEMSET) == StringRef("memset");
+
+ RTLIB::LibcallImpl MemsetImpl = TLI->getLibcallImpl(RTLIB::MEMSET);
+ bool LowersToMemset = MemsetImpl == RTLIB::impl_memset;
+
// If we're going to use bzero, make sure not to tail call unless the
// subsequent return doesn't need a value, as bzero doesn't return the first
// arg unlike memset.
>From 1693ab1d8bc477b81cadb72ec8a9eb6f5fa0c4ec Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Tue, 4 Nov 2025 10:51:44 -0800
Subject: [PATCH 2/3] Remove getMemcpyName
---
llvm/include/llvm/CodeGen/TargetLowering.h | 5 +----
llvm/include/llvm/IR/RuntimeLibcalls.h | 6 +++---
llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp | 2 +-
llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp | 2 +-
4 files changed, 6 insertions(+), 9 deletions(-)
diff --git a/llvm/include/llvm/CodeGen/TargetLowering.h b/llvm/include/llvm/CodeGen/TargetLowering.h
index 78f63b4406eb0..b229659415d55 100644
--- a/llvm/include/llvm/CodeGen/TargetLowering.h
+++ b/llvm/include/llvm/CodeGen/TargetLowering.h
@@ -3620,10 +3620,7 @@ class LLVM_ABI TargetLoweringBase {
return RTLIB::RuntimeLibcallsInfo::getLibcallImplName(Call);
}
- const char *getMemcpyName() const {
- // FIXME: Return StringRef
- return Libcalls.getMemcpyName().data();
- }
+ RTLIB::LibcallImpl getMemcpyImpl() const { return Libcalls.getMemcpyImpl(); }
/// Check if this is valid libcall for the current module, otherwise
/// RTLIB::Unsupported.
diff --git a/llvm/include/llvm/IR/RuntimeLibcalls.h b/llvm/include/llvm/IR/RuntimeLibcalls.h
index ab14ed44fed52..bae760b3f981d 100644
--- a/llvm/include/llvm/IR/RuntimeLibcalls.h
+++ b/llvm/include/llvm/IR/RuntimeLibcalls.h
@@ -134,13 +134,13 @@ struct RuntimeLibcallsInfo {
/// Return a function name compatible with RTLIB::MEMCPY, or nullptr if fully
/// unsupported.
- StringRef getMemcpyName() const {
+ RTLIB::LibcallImpl getMemcpyImpl() const {
RTLIB::LibcallImpl Memcpy = getLibcallImpl(RTLIB::MEMCPY);
if (Memcpy != RTLIB::Unsupported)
- return getLibcallImplName(Memcpy);
+ return Memcpy;
// Fallback to memmove if memcpy isn't available.
- return getLibcallName(RTLIB::MEMMOVE);
+ return getLibcallImpl(RTLIB::MEMMOVE);
}
bool isAvailable(RTLIB::LibcallImpl Impl) const {
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index 52c43a4ac4a04..d02f097fef829 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -776,7 +776,7 @@ llvm::createMemLibcall(MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI,
break;
case TargetOpcode::G_MEMCPY:
RTLibcall = RTLIB::MEMCPY;
- Name = TLI.getMemcpyName();
+ Name = TLI.getLibcallImplName(TLI.getMemcpyImpl()).data();
Args[0].Flags[0].setReturned();
break;
case TargetOpcode::G_MEMMOVE:
diff --git a/llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp b/llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
index 620d3d3d02daa..d738dc4eea36d 100644
--- a/llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
+++ b/llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp
@@ -244,7 +244,7 @@ static bool canEmitMemcpy(const TargetMachine *TM, Function *F) {
if (!TM)
return true;
const TargetLowering *TLI = TM->getSubtargetImpl(*F)->getTargetLowering();
- return TLI->getMemcpyName() != nullptr;
+ return TLI->getMemcpyImpl() != RTLIB::Unsupported;
}
// Return a value appropriate for use with the memset_pattern16 libcall, if
>From 302fdbfb9c949a9cd08fd2756a2b173568ebc251 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Tue, 4 Nov 2025 10:53:54 -0800
Subject: [PATCH 3/3] Fix
---
llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 3365c507b8f03..ff6a7b2cf5462 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -9257,7 +9257,7 @@ SDValue SelectionDAG::getMemcpy(
// FIXME: pass in SDLoc
TargetLowering::CallLoweringInfo CLI(*this);
bool IsTailCall = false;
- RTLIB::LibcallImpl MemCpyImpl = TLI->getLibcallImpl(RTLIB::MEMCPY);
+ RTLIB::LibcallImpl MemCpyImpl = TLI->getMemcpyImpl();
if (OverrideTailCall.has_value()) {
IsTailCall = *OverrideTailCall;
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