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[PowerPC] using milicode call for strlen instead of lib call #153600

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Merged
merged 6 commits into from
Sep 19, 2025
Merged

[PowerPC] using milicode call for strlen instead of lib call #153600

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4ad1f1e
implement using milicode for strlen instead of libcall
diggerlin Aug 13, 2025
d5016bc
fix an error
diggerlin Aug 14, 2025
b3bf591
address comment
diggerlin Aug 20, 2025
a404747
address comment
diggerlin Aug 22, 2025
904b92a
rebase the code after NFC patch landed
diggerlin Sep 16, 2025
c4364f8
nit change
diggerlin Sep 16, 2025
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3 changes: 3 additions & 0 deletions llvm/include/llvm/CodeGen/SelectionDAG.h
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Expand Up @@ -1259,6 +1259,9 @@ class SelectionDAG {
std::pair<SDValue, SDValue> getMemcmp(SDValue Chain, const SDLoc &dl,
SDValue Dst, SDValue Src, SDValue Size,
const CallInst *CI);
LLVM_ABI std::pair<SDValue, SDValue>
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@lei137 lei137 Sep 17, 2025

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nit: can we add some doc on what this function does?
What is the difference between returing LLVM_ABI std::pair<SDValue, SDValue> vs just std::pair<SDValue, SDValue>? I see that getMemcmp() doesn't use LLVM_ABI

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@diggerlin diggerlin Sep 19, 2025 •
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All the member functions of SelectionDAG has LLVM_ABI, when I worked on the patch #147093, I forgot to add the LLVM_ABI for getMemcmp(), I added it in the patch before, but Roland suggested a NFC patch for it(#153600 (comment)) . I will create a NFC patch to add LLVM_ABI for getMemcmp() later.

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@diggerlin diggerlin Sep 19, 2025 •
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nit: can we add some doc on what this function does?

Sorry to miss your comment , I will add doc the getMemcp and getStrlen in the same NFC patch of adding LLVM_ABI for getMemcmp().

getStrlen(SDValue Chain, const SDLoc &dl, SDValue Src, const CallInst *CI);

/* \p CI if not null is the memset call being lowered.
* \p OverrideTailCall is an optional parameter that can be used to override
* the tail call optimization decision. */
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2 changes: 1 addition & 1 deletion llvm/include/llvm/CodeGen/SelectionDAGTargetInfo.h
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Expand Up @@ -162,7 +162,7 @@ class SelectionDAGTargetInfo {

virtual std::pair<SDValue, SDValue>
EmitTargetCodeForStrlen(SelectionDAG &DAG, const SDLoc &DL, SDValue Chain,
SDValue Src, MachinePointerInfo SrcPtrInfo) const {
SDValue Src, const CallInst *CI) const {
return std::make_pair(SDValue(), SDValue());
}

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3 changes: 3 additions & 0 deletions llvm/include/llvm/IR/RuntimeLibcalls.td
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Expand Up @@ -297,6 +297,7 @@ def MEMMOVE : RuntimeLibcall;
def MEMSET : RuntimeLibcall;
def CALLOC : RuntimeLibcall;
def BZERO : RuntimeLibcall;
def STRLEN : RuntimeLibcall;

// Element-wise unordered-atomic memory of different sizes
foreach MemSize = [1, 2, 4, 8, 16] in {
Expand Down Expand Up @@ -2272,13 +2273,15 @@ defset list<RuntimeLibcallImpl> PPC64AIXCallList = {
def ___memmove64 : RuntimeLibcallImpl<MEMCPY>;
def ___memset64 : RuntimeLibcallImpl<MEMSET>;
def ___bzero64 : RuntimeLibcallImpl<BZERO>;
def ___strlen64 : RuntimeLibcallImpl<STRLEN>;
}

defset list<RuntimeLibcallImpl> PPC32AIXCallList = {
def ___memcmp : RuntimeLibcallImpl<MEMCMP>;
def ___memmove : RuntimeLibcallImpl<MEMMOVE>;
def ___memset : RuntimeLibcallImpl<MEMSET>;
def ___bzero : RuntimeLibcallImpl<BZERO>;
def ___strlen : RuntimeLibcallImpl<STRLEN>;
}

defvar PPCOverrides = !foreach(entry, PPCRuntimeLibcalls, entry.Provides);
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27 changes: 27 additions & 0 deletions llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
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Expand Up @@ -9094,6 +9094,33 @@ SelectionDAG::getMemcmp(SDValue Chain, const SDLoc &dl, SDValue Mem0,
return TLI->LowerCallTo(CLI);
}

std::pair<SDValue, SDValue> SelectionDAG::getStrlen(SDValue Chain,
const SDLoc &dl,
SDValue Src,
const CallInst *CI) {
const char *LibCallName = TLI->getLibcallName(RTLIB::STRLEN);
if (!LibCallName)
return {};

// Emit a library call.
TargetLowering::ArgListTy Args = {
{Src, PointerType::getUnqual(*getContext())}};

TargetLowering::CallLoweringInfo CLI(*this);
bool IsTailCall =
isInTailCallPositionWrapper(CI, this, /*AllowReturnsFirstArg*/ true);

CLI.setDebugLoc(dl)
.setChain(Chain)
.setLibCallee(TLI->getLibcallCallingConv(RTLIB::STRLEN), CI->getType(),
getExternalSymbol(
LibCallName, TLI->getProgramPointerTy(getDataLayout())),
std::move(Args))
.setTailCall(IsTailCall);

return TLI->LowerCallTo(CLI);
}

SDValue SelectionDAG::getMemcpy(
SDValue Chain, const SDLoc &dl, SDValue Dst, SDValue Src, SDValue Size,
Align Alignment, bool isVol, bool AlwaysInline, const CallInst *CI,
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5 changes: 2 additions & 3 deletions llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
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Expand Up @@ -9335,9 +9335,8 @@ bool SelectionDAGBuilder::visitStrLenCall(const CallInst &I) {
const Value *Arg0 = I.getArgOperand(0);

const SelectionDAGTargetInfo &TSI = DAG.getSelectionDAGInfo();
std::pair<SDValue, SDValue> Res =
TSI.EmitTargetCodeForStrlen(DAG, getCurSDLoc(), DAG.getRoot(),
getValue(Arg0), MachinePointerInfo(Arg0));
std::pair<SDValue, SDValue> Res = TSI.EmitTargetCodeForStrlen(
DAG, getCurSDLoc(), DAG.getRoot(), getValue(Arg0), &I);
if (Res.first.getNode()) {
processIntegerCallValue(I, Res.first, false);
PendingLoads.push_back(Res.second);
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7 changes: 7 additions & 0 deletions llvm/lib/Target/PowerPC/PPCSelectionDAGInfo.cpp
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Expand Up @@ -28,3 +28,10 @@ std::pair<SDValue, SDValue> PPCSelectionDAGInfo::EmitTargetCodeForMemcmp(
SDValue Op3, const CallInst *CI) const {
return DAG.getMemcmp(Chain, dl, Op1, Op2, Op3, CI);
}

std::pair<SDValue, SDValue>
PPCSelectionDAGInfo::EmitTargetCodeForStrlen(SelectionDAG &DAG, const SDLoc &DL,
SDValue Chain, SDValue Src,
const CallInst *CI) const {
return DAG.getStrlen(Chain, DL, Src, CI);
}
3 changes: 3 additions & 0 deletions llvm/lib/Target/PowerPC/PPCSelectionDAGInfo.h
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Expand Up @@ -25,6 +25,9 @@ class PPCSelectionDAGInfo : public SelectionDAGTargetInfo {
EmitTargetCodeForMemcmp(SelectionDAG &DAG, const SDLoc &dl, SDValue Chain,
SDValue Op1, SDValue Op2, SDValue Op3,
const CallInst *CI) const override;
std::pair<SDValue, SDValue>
EmitTargetCodeForStrlen(SelectionDAG &DAG, const SDLoc &DL, SDValue Chain,
SDValue Src, const CallInst *CI) const override;
};

} // namespace llvm
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2 changes: 1 addition & 1 deletion llvm/lib/Target/SystemZ/SystemZSelectionDAGInfo.cpp
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Expand Up @@ -263,7 +263,7 @@ static std::pair<SDValue, SDValue> getBoundedStrlen(SelectionDAG &DAG,

std::pair<SDValue, SDValue> SystemZSelectionDAGInfo::EmitTargetCodeForStrlen(
SelectionDAG &DAG, const SDLoc &DL, SDValue Chain, SDValue Src,
MachinePointerInfo SrcPtrInfo) const {
const CallInst *CI) const {
EVT PtrVT = Src.getValueType();
return getBoundedStrlen(DAG, DL, Chain, Src, DAG.getConstant(0, DL, PtrVT));
}
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3 changes: 1 addition & 2 deletions llvm/lib/Target/SystemZ/SystemZSelectionDAGInfo.h
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Expand Up @@ -61,8 +61,7 @@ class SystemZSelectionDAGInfo : public SelectionDAGTargetInfo {

std::pair<SDValue, SDValue>
EmitTargetCodeForStrlen(SelectionDAG &DAG, const SDLoc &DL, SDValue Chain,
SDValue Src,
MachinePointerInfo SrcPtrInfo) const override;
SDValue Src, const CallInst *CI) const override;

std::pair<SDValue, SDValue>
EmitTargetCodeForStrnlen(SelectionDAG &DAG, const SDLoc &DL, SDValue Chain,
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2 changes: 1 addition & 1 deletion llvm/test/CodeGen/PowerPC/milicode32.ll
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Expand Up @@ -42,7 +42,7 @@ define i32 @strlen_test(ptr noundef %str) nounwind {
; CHECK-AIX-32-P9-NEXT: stwu r1, -64(r1)
; CHECK-AIX-32-P9-NEXT: stw r0, 72(r1)
; CHECK-AIX-32-P9-NEXT: stw r3, 60(r1)
; CHECK-AIX-32-P9-NEXT: bl .strlen[PR]
; CHECK-AIX-32-P9-NEXT: bl .___strlen[PR]
; CHECK-AIX-32-P9-NEXT: nop
; CHECK-AIX-32-P9-NEXT: addi r1, r1, 64
; CHECK-AIX-32-P9-NEXT: lwz r0, 8(r1)
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2 changes: 1 addition & 1 deletion llvm/test/CodeGen/PowerPC/milicode64.ll
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Expand Up @@ -85,7 +85,7 @@ define i64 @strlen_test(ptr noundef %str) nounwind {
; CHECK-AIX-64-P9-NEXT: stdu r1, -128(r1)
; CHECK-AIX-64-P9-NEXT: std r0, 144(r1)
; CHECK-AIX-64-P9-NEXT: std r3, 120(r1)
; CHECK-AIX-64-P9-NEXT: bl .strlen[PR]
; CHECK-AIX-64-P9-NEXT: bl .___strlen64[PR]
; CHECK-AIX-64-P9-NEXT: nop
; CHECK-AIX-64-P9-NEXT: addi r1, r1, 128
; CHECK-AIX-64-P9-NEXT: ld r0, 16(r1)
Expand Down