[llvm] [PowerPC][NFC] Update lowering STXVP to STXV in Oct word spilling (PR #143952)
Lei Huang via llvm-commits
llvm-commits at lists.llvm.org
Thu Jun 12 12:16:04 PDT 2025
https://github.com/lei137 created https://github.com/llvm/llvm-project/pull/143952
Simpliy handling for spilling of acc reg with stx by removing
explicit register arithmetic and clean up code gen for register
mapping used in stxvp spilling.
>From 4681ce5de51706d5317a671c55a274120accac8f Mon Sep 17 00:00:00 2001
From: Lei Huang <lei at ca.ibm.com>
Date: Thu, 12 Jun 2025 13:52:42 -0500
Subject: [PATCH 1/2] Revert "[PowerPC][NFC] Update lowering STXVP to STXV in
Oct word spilling (#142220)"
This reverts commit edf636afe405ff90da7bf1834aa334bd52bc861e.
Checked in the wrong branch.
---
llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp | 93 +++++++++++----------
1 file changed, 50 insertions(+), 43 deletions(-)
diff --git a/llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp b/llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp
index 9dc69e203b0da..45183af0b7984 100644
--- a/llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp
+++ b/llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp
@@ -1238,6 +1238,42 @@ static void emitAccSpillRestoreInfo(MachineBasicBlock &MBB, bool IsPrimed,
#endif
}
+static void spillRegPairs(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator II, DebugLoc DL,
+ const TargetInstrInfo &TII, Register SrcReg,
+ unsigned FrameIndex, bool IsLittleEndian,
+ bool IsKilled, bool TwoPairs) {
+ unsigned Offset = 0;
+ // The register arithmetic in this function does not support virtual
+ // registers.
+ assert(!SrcReg.isVirtual() &&
+ "Spilling register pairs does not support virtual registers.");
+
+ if (TwoPairs)
+ Offset = IsLittleEndian ? 48 : 0;
+ else
+ Offset = IsLittleEndian ? 16 : 0;
+ Register Reg = (SrcReg > PPC::VSRp15) ? PPC::V0 + (SrcReg - PPC::VSRp16) * 2
+ : PPC::VSL0 + (SrcReg - PPC::VSRp0) * 2;
+ addFrameReference(BuildMI(MBB, II, DL, TII.get(PPC::STXV))
+ .addReg(Reg, getKillRegState(IsKilled)),
+ FrameIndex, Offset);
+ Offset += IsLittleEndian ? -16 : 16;
+ addFrameReference(BuildMI(MBB, II, DL, TII.get(PPC::STXV))
+ .addReg(Reg + 1, getKillRegState(IsKilled)),
+ FrameIndex, Offset);
+ if (TwoPairs) {
+ Offset += IsLittleEndian ? -16 : 16;
+ addFrameReference(BuildMI(MBB, II, DL, TII.get(PPC::STXV))
+ .addReg(Reg + 2, getKillRegState(IsKilled)),
+ FrameIndex, Offset);
+ Offset += IsLittleEndian ? -16 : 16;
+ addFrameReference(BuildMI(MBB, II, DL, TII.get(PPC::STXV))
+ .addReg(Reg + 3, getKillRegState(IsKilled)),
+ FrameIndex, Offset);
+ }
+}
+
/// Remove any STXVP[X] instructions and split them out into a pair of
/// STXV[X] instructions if --disable-auto-paired-vec-st is specified on
/// the command line.
@@ -1254,21 +1290,8 @@ void PPCRegisterInfo::lowerOctWordSpilling(MachineBasicBlock::iterator II,
Register SrcReg = MI.getOperand(0).getReg();
bool IsLittleEndian = Subtarget.isLittleEndian();
bool IsKilled = MI.getOperand(0).isKill();
-
- assert(PPC::VSRpRCRegClass.contains(SrcReg) &&
- "Expecting STXVP to be utilizing a VSRp register.");
-
- addFrameReference(
- BuildMI(MBB, II, DL, TII.get(PPC::STXV))
- .addReg(TargetRegisterInfo::getSubReg(SrcReg, PPC::sub_vsx0),
- getKillRegState(IsKilled)),
- FrameIndex, IsLittleEndian ? 16 : 0);
- addFrameReference(
- BuildMI(MBB, II, DL, TII.get(PPC::STXV))
- .addReg(TargetRegisterInfo::getSubReg(SrcReg, PPC::sub_vsx1),
- getKillRegState(IsKilled)),
- FrameIndex, IsLittleEndian ? 0 : 16);
-
+ spillRegPairs(MBB, II, DL, TII, SrcReg, FrameIndex, IsLittleEndian, IsKilled,
+ /* TwoPairs */ false);
// Discard the original instruction.
MBB.erase(II);
}
@@ -1302,6 +1325,8 @@ void PPCRegisterInfo::lowerACCSpilling(MachineBasicBlock::iterator II,
bool IsKilled = MI.getOperand(0).isKill();
bool IsPrimed = PPC::ACCRCRegClass.contains(SrcReg);
+ Register Reg =
+ PPC::VSRp0 + (SrcReg - (IsPrimed ? PPC::ACC0 : PPC::UACC0)) * 2;
bool IsLittleEndian = Subtarget.isLittleEndian();
emitAccSpillRestoreInfo(MBB, IsPrimed, false);
@@ -1312,34 +1337,16 @@ void PPCRegisterInfo::lowerACCSpilling(MachineBasicBlock::iterator II,
// adjust the offset of the store that is within the 64-byte stack slot.
if (IsPrimed)
BuildMI(MBB, II, DL, TII.get(PPC::XXMFACC), SrcReg).addReg(SrcReg);
- if (DisableAutoPairedVecSt) {
- auto spillPair = [&](Register Reg, int Offset) {
- addFrameReference(
- BuildMI(MBB, II, DL, TII.get(PPC::STXV))
- .addReg(TargetRegisterInfo::getSubReg(Reg, PPC::sub_vsx0),
- getKillRegState(IsKilled)),
- FrameIndex, Offset);
- addFrameReference(
- BuildMI(MBB, II, DL, TII.get(PPC::STXV))
- .addReg(TargetRegisterInfo::getSubReg(Reg, PPC::sub_vsx1),
- getKillRegState(IsKilled)),
- FrameIndex, IsLittleEndian ? Offset - 16 : Offset + 16);
- };
- spillPair(TargetRegisterInfo::getSubReg(SrcReg, PPC::sub_pair0),
- IsLittleEndian ? 48 : 0);
- spillPair(TargetRegisterInfo::getSubReg(SrcReg, PPC::sub_pair1),
- IsLittleEndian ? 16 : 32);
- } else {
- addFrameReference(
- BuildMI(MBB, II, DL, TII.get(PPC::STXVP))
- .addReg(TargetRegisterInfo::getSubReg(SrcReg, PPC::sub_pair0),
- getKillRegState(IsKilled)),
- FrameIndex, IsLittleEndian ? 32 : 0);
- addFrameReference(
- BuildMI(MBB, II, DL, TII.get(PPC::STXVP))
- .addReg(TargetRegisterInfo::getSubReg(SrcReg, PPC::sub_pair1),
- getKillRegState(IsKilled)),
- FrameIndex, IsLittleEndian ? 0 : 32);
+ if (DisableAutoPairedVecSt)
+ spillRegPairs(MBB, II, DL, TII, Reg, FrameIndex, IsLittleEndian, IsKilled,
+ /* TwoPairs */ true);
+ else {
+ addFrameReference(BuildMI(MBB, II, DL, TII.get(PPC::STXVP))
+ .addReg(Reg, getKillRegState(IsKilled)),
+ FrameIndex, IsLittleEndian ? 32 : 0);
+ addFrameReference(BuildMI(MBB, II, DL, TII.get(PPC::STXVP))
+ .addReg(Reg + 1, getKillRegState(IsKilled)),
+ FrameIndex, IsLittleEndian ? 0 : 32);
}
if (IsPrimed && !IsKilled)
BuildMI(MBB, II, DL, TII.get(PPC::XXMTACC), SrcReg).addReg(SrcReg);
>From 63c233dd8308ce10b8bde98bfb491bd7ef63f2e4 Mon Sep 17 00:00:00 2001
From: Lei Huang <lei at ca.ibm.com>
Date: Fri, 30 May 2025 11:15:07 -0500
Subject: [PATCH 2/2] Simpliy handling for spilling of acc reg with stx by
removing explicit register arithmetic and clean up code gen for register
mapping used in stxvp spilling.
---
llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp | 88 ++++++++++-----------
llvm/lib/Target/PowerPC/PPCRegisterInfo.h | 5 ++
2 files changed, 47 insertions(+), 46 deletions(-)
diff --git a/llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp b/llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp
index 45183af0b7984..ea34c1aba82e3 100644
--- a/llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp
+++ b/llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp
@@ -1238,40 +1238,28 @@ static void emitAccSpillRestoreInfo(MachineBasicBlock &MBB, bool IsPrimed,
#endif
}
-static void spillRegPairs(MachineBasicBlock &MBB,
- MachineBasicBlock::iterator II, DebugLoc DL,
- const TargetInstrInfo &TII, Register SrcReg,
- unsigned FrameIndex, bool IsLittleEndian,
- bool IsKilled, bool TwoPairs) {
- unsigned Offset = 0;
- // The register arithmetic in this function does not support virtual
- // registers.
- assert(!SrcReg.isVirtual() &&
+void PPCRegisterInfo::spillRegPair(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator II, DebugLoc DL,
+ const TargetInstrInfo &TII,
+ unsigned FrameIndex, bool IsLittleEndian,
+ bool IsKilled, Register Reg,
+ int Offset) const {
+
+ // This function does not support virtual registers.
+ assert(!Reg.isVirtual() &&
"Spilling register pairs does not support virtual registers.");
- if (TwoPairs)
- Offset = IsLittleEndian ? 48 : 0;
- else
- Offset = IsLittleEndian ? 16 : 0;
- Register Reg = (SrcReg > PPC::VSRp15) ? PPC::V0 + (SrcReg - PPC::VSRp16) * 2
- : PPC::VSL0 + (SrcReg - PPC::VSRp0) * 2;
- addFrameReference(BuildMI(MBB, II, DL, TII.get(PPC::STXV))
- .addReg(Reg, getKillRegState(IsKilled)),
- FrameIndex, Offset);
- Offset += IsLittleEndian ? -16 : 16;
- addFrameReference(BuildMI(MBB, II, DL, TII.get(PPC::STXV))
- .addReg(Reg + 1, getKillRegState(IsKilled)),
- FrameIndex, Offset);
- if (TwoPairs) {
- Offset += IsLittleEndian ? -16 : 16;
- addFrameReference(BuildMI(MBB, II, DL, TII.get(PPC::STXV))
- .addReg(Reg + 2, getKillRegState(IsKilled)),
- FrameIndex, Offset);
- Offset += IsLittleEndian ? -16 : 16;
- addFrameReference(BuildMI(MBB, II, DL, TII.get(PPC::STXV))
- .addReg(Reg + 3, getKillRegState(IsKilled)),
- FrameIndex, Offset);
- }
+ addFrameReference(
+ BuildMI(MBB, II, DL, TII.get(PPC::STXV))
+ .addReg(TargetRegisterInfo::getSubReg(Reg, PPC::sub_vsx0),
+ getKillRegState(IsKilled)),
+ FrameIndex, Offset);
+
+ addFrameReference(
+ BuildMI(MBB, II, DL, TII.get(PPC::STXV))
+ .addReg(TargetRegisterInfo::getSubReg(Reg, PPC::sub_vsx1),
+ getKillRegState(IsKilled)),
+ FrameIndex, IsLittleEndian ? Offset - 16 : Offset + 16);
}
/// Remove any STXVP[X] instructions and split them out into a pair of
@@ -1290,8 +1278,10 @@ void PPCRegisterInfo::lowerOctWordSpilling(MachineBasicBlock::iterator II,
Register SrcReg = MI.getOperand(0).getReg();
bool IsLittleEndian = Subtarget.isLittleEndian();
bool IsKilled = MI.getOperand(0).isKill();
- spillRegPairs(MBB, II, DL, TII, SrcReg, FrameIndex, IsLittleEndian, IsKilled,
- /* TwoPairs */ false);
+
+ spillRegPair(MBB, II, DL, TII, FrameIndex, IsLittleEndian, IsKilled, SrcReg,
+ IsLittleEndian ? 16 : 0);
+
// Discard the original instruction.
MBB.erase(II);
}
@@ -1325,8 +1315,6 @@ void PPCRegisterInfo::lowerACCSpilling(MachineBasicBlock::iterator II,
bool IsKilled = MI.getOperand(0).isKill();
bool IsPrimed = PPC::ACCRCRegClass.contains(SrcReg);
- Register Reg =
- PPC::VSRp0 + (SrcReg - (IsPrimed ? PPC::ACC0 : PPC::UACC0)) * 2;
bool IsLittleEndian = Subtarget.isLittleEndian();
emitAccSpillRestoreInfo(MBB, IsPrimed, false);
@@ -1337,16 +1325,24 @@ void PPCRegisterInfo::lowerACCSpilling(MachineBasicBlock::iterator II,
// adjust the offset of the store that is within the 64-byte stack slot.
if (IsPrimed)
BuildMI(MBB, II, DL, TII.get(PPC::XXMFACC), SrcReg).addReg(SrcReg);
- if (DisableAutoPairedVecSt)
- spillRegPairs(MBB, II, DL, TII, Reg, FrameIndex, IsLittleEndian, IsKilled,
- /* TwoPairs */ true);
- else {
- addFrameReference(BuildMI(MBB, II, DL, TII.get(PPC::STXVP))
- .addReg(Reg, getKillRegState(IsKilled)),
- FrameIndex, IsLittleEndian ? 32 : 0);
- addFrameReference(BuildMI(MBB, II, DL, TII.get(PPC::STXVP))
- .addReg(Reg + 1, getKillRegState(IsKilled)),
- FrameIndex, IsLittleEndian ? 0 : 32);
+ if (DisableAutoPairedVecSt) {
+ spillRegPair(MBB, II, DL, TII, FrameIndex, IsLittleEndian, IsKilled,
+ TargetRegisterInfo::getSubReg(SrcReg, PPC::sub_pair0),
+ IsLittleEndian ? 48 : 0);
+ spillRegPair(MBB, II, DL, TII, FrameIndex, IsLittleEndian, IsKilled,
+ TargetRegisterInfo::getSubReg(SrcReg, PPC::sub_pair1),
+ IsLittleEndian ? 16 : 32);
+ } else {
+ addFrameReference(
+ BuildMI(MBB, II, DL, TII.get(PPC::STXVP))
+ .addReg(TargetRegisterInfo::getSubReg(SrcReg, PPC::sub_pair0),
+ getKillRegState(IsKilled)),
+ FrameIndex, IsLittleEndian ? 32 : 0);
+ addFrameReference(
+ BuildMI(MBB, II, DL, TII.get(PPC::STXVP))
+ .addReg(TargetRegisterInfo::getSubReg(SrcReg, PPC::sub_pair1),
+ getKillRegState(IsKilled)),
+ FrameIndex, IsLittleEndian ? 0 : 32);
}
if (IsPrimed && !IsKilled)
BuildMI(MBB, II, DL, TII.get(PPC::XXMTACC), SrcReg).addReg(SrcReg);
diff --git a/llvm/lib/Target/PowerPC/PPCRegisterInfo.h b/llvm/lib/Target/PowerPC/PPCRegisterInfo.h
index 4b66ece534112..849f856b5419e 100644
--- a/llvm/lib/Target/PowerPC/PPCRegisterInfo.h
+++ b/llvm/lib/Target/PowerPC/PPCRegisterInfo.h
@@ -58,6 +58,11 @@ class PPCRegisterInfo : public PPCGenRegisterInfo {
DenseMap<unsigned, unsigned> ImmToIdxMap;
const PPCTargetMachine &TM;
+ void spillRegPair(MachineBasicBlock &MBB, MachineBasicBlock::iterator II,
+ DebugLoc DL, const TargetInstrInfo &TII,
+ unsigned FrameIndex, bool IsLittleEndian, bool IsKilled,
+ Register Reg, int Offset) const;
+
public:
PPCRegisterInfo(const PPCTargetMachine &TM);
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