[NFC] Refactor looping over recomputeLiveIns into function #88040
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@llvm/pr-subscribers-backend-x86 @llvm/pr-subscribers-backend-powerpc Author: Kai Nacke (redstar) Changes#79940 put calls to recomputeLiveIns into Note that this changes the order in which recomputeLiveIns is called. For example, only begins to recompute the live-ins for LoopMBB after the computation for ExitMBB Full diff: https://github.com/llvm/llvm-project/pull/88040.diff 9 Files Affected:
diff --git a/llvm/include/llvm/CodeGen/LivePhysRegs.h b/llvm/include/llvm/CodeGen/LivePhysRegs.h
index 1d40b1cbb0eaa3..a2447e7702c77f 100644
--- a/llvm/include/llvm/CodeGen/LivePhysRegs.h
+++ b/llvm/include/llvm/CodeGen/LivePhysRegs.h
@@ -39,6 +39,8 @@
namespace llvm {
+template <typename T> class ArrayRef;
+
class MachineInstr;
class MachineFunction;
class MachineOperand;
@@ -207,6 +209,18 @@ static inline bool recomputeLiveIns(MachineBasicBlock &MBB) {
return oldLiveIns != newLiveIns;
}
+/// Convenience function for recomputing live-in's for a set of MBBs until the
+/// computation converges.
+static inline void
+fullyRecomputeLiveIns(ArrayRef<MachineBasicBlock *> MBBs) {
+ bool AnyChange;
+ do {
+ AnyChange = false;
+ for (MachineBasicBlock *MBB : MBBs)
+ AnyChange = recomputeLiveIns(*MBB) || AnyChange;
+ } while (AnyChange);
+}
+
} // end namespace llvm
#endif // LLVM_CODEGEN_LIVEPHYSREGS_H
diff --git a/llvm/lib/CodeGen/BranchFolding.cpp b/llvm/lib/CodeGen/BranchFolding.cpp
index ecf7bc30913f51..55aa1d438b2a66 100644
--- a/llvm/lib/CodeGen/BranchFolding.cpp
+++ b/llvm/lib/CodeGen/BranchFolding.cpp
@@ -2047,12 +2047,8 @@ bool BranchFolder::HoistCommonCodeInSuccs(MachineBasicBlock *MBB) {
MBB->splice(Loc, TBB, TBB->begin(), TIB);
FBB->erase(FBB->begin(), FIB);
- if (UpdateLiveIns) {
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*TBB) || recomputeLiveIns(*FBB);
- } while (anyChange);
- }
+ if (UpdateLiveIns)
+ fullyRecomputeLiveIns({TBB, FBB});
++NumHoist;
return true;
diff --git a/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp b/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
index 5cc612e89162af..419c141121c325 100644
--- a/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
@@ -4325,10 +4325,7 @@ AArch64FrameLowering::inlineStackProbeLoopExactMultiple(
ExitMBB->transferSuccessorsAndUpdatePHIs(&MBB);
MBB.addSuccessor(LoopMBB);
// Update liveins.
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*ExitMBB) || recomputeLiveIns(*LoopMBB);
- } while (anyChange);
+ fullyRecomputeLiveIns({ExitMBB, LoopMBB});
return ExitMBB->begin();
}
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
index 22687b0e31c284..9f7176694d540a 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -9557,15 +9557,8 @@ AArch64InstrInfo::probedStackAlloc(MachineBasicBlock::iterator MBBI,
MBB.addSuccessor(LoopTestMBB);
// Update liveins.
- if (MF.getRegInfo().reservedRegsFrozen()) {
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*ExitMBB) ||
- recomputeLiveIns(*LoopBodyMBB) ||
- recomputeLiveIns(*LoopTestMBB);
- } while (anyChange);
- ;
- }
+ if (MF.getRegInfo().reservedRegsFrozen())
+ fullyRecomputeLiveIns({ExitMBB, LoopBodyMBB, LoopTestMBB});
return ExitMBB->begin();
}
diff --git a/llvm/lib/Target/ARM/ARMLowOverheadLoops.cpp b/llvm/lib/Target/ARM/ARMLowOverheadLoops.cpp
index 8629551152cb64..ea5dd5427ce720 100644
--- a/llvm/lib/Target/ARM/ARMLowOverheadLoops.cpp
+++ b/llvm/lib/Target/ARM/ARMLowOverheadLoops.cpp
@@ -1806,13 +1806,7 @@ void ARMLowOverheadLoops::Expand(LowOverheadLoop &LoLoop) {
PostOrderLoopTraversal DFS(LoLoop.ML, *MLI);
DFS.ProcessLoop();
const SmallVectorImpl<MachineBasicBlock*> &PostOrder = DFS.getOrder();
- bool anyChange = false;
- do {
- anyChange = false;
- for (auto *MBB : PostOrder) {
- anyChange = recomputeLiveIns(*MBB) || anyChange;
- }
- } while (anyChange);
+ fullyRecomputeLiveIns(PostOrder);
for (auto *MBB : reverse(PostOrder))
recomputeLivenessFlags(*MBB);
diff --git a/llvm/lib/Target/PowerPC/PPCExpandAtomicPseudoInsts.cpp b/llvm/lib/Target/PowerPC/PPCExpandAtomicPseudoInsts.cpp
index b43eee8fdd8c0f..b3cfcb2aa14405 100644
--- a/llvm/lib/Target/PowerPC/PPCExpandAtomicPseudoInsts.cpp
+++ b/llvm/lib/Target/PowerPC/PPCExpandAtomicPseudoInsts.cpp
@@ -208,10 +208,7 @@ bool PPCExpandAtomicPseudo::expandAtomicRMW128(
.addMBB(LoopMBB);
CurrentMBB->addSuccessor(LoopMBB);
CurrentMBB->addSuccessor(ExitMBB);
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*ExitMBB) || recomputeLiveIns(*LoopMBB);
- } while (anyChange);
+ fullyRecomputeLiveIns({ExitMBB, LoopMBB});
NMBBI = MBB.end();
MI.eraseFromParent();
return true;
@@ -288,11 +285,7 @@ bool PPCExpandAtomicPseudo::expandAtomicCmpSwap128(
CurrentMBB->addSuccessor(LoopCmpMBB);
CurrentMBB->addSuccessor(ExitMBB);
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*ExitMBB) || recomputeLiveIns(*CmpSuccMBB) ||
- recomputeLiveIns(*LoopCmpMBB);
- } while (anyChange);
+ fullyRecomputeLiveIns({ExitMBB, CmpSuccMBB, LoopCmpMBB});
NMBBI = MBB.end();
MI.eraseFromParent();
return true;
diff --git a/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp b/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
index 6dcb59a3a57f85..04e9f9e2366edd 100644
--- a/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
@@ -1435,11 +1435,7 @@ void PPCFrameLowering::inlineStackProbe(MachineFunction &MF,
ProbeLoopBodyMBB->addSuccessor(ProbeLoopBodyMBB);
}
// Update liveins.
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*ProbeExitMBB) ||
- recomputeLiveIns(*ProbeLoopBodyMBB);
- } while (anyChange);
+ fullyRecomputeLiveIns({ProbeExitMBB, ProbeLoopBodyMBB});
return ProbeExitMBB;
};
// For case HasBP && MaxAlign > 1, we have to realign the SP by performing
@@ -1531,10 +1527,7 @@ void PPCFrameLowering::inlineStackProbe(MachineFunction &MF,
buildDefCFAReg(*ExitMBB, ExitMBB->begin(), SPReg);
}
// Update liveins.
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*ExitMBB) || recomputeLiveIns(*LoopMBB);
- } while (anyChange);
+ fullyRecomputeLiveIns({ExitMBB, LoopMBB});
}
}
++NumPrologProbed;
diff --git a/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp b/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
index 4897b37d8eb1ef..50ecd6e0744147 100644
--- a/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
@@ -824,10 +824,7 @@ void SystemZELFFrameLowering::inlineStackProbe(
StackAllocMI->eraseFromParent();
if (DoneMBB != nullptr) {
// Compute the live-in lists for the new blocks.
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*DoneMBB) || recomputeLiveIns(*LoopMBB);
- } while (anyChange);
+ fullyRecomputeLiveIns({DoneMBB, LoopMBB});
}
}
@@ -1425,10 +1422,7 @@ void SystemZXPLINKFrameLowering::inlineStackProbe(
StackAllocMI->eraseFromParent();
// Compute the live-in lists for the new blocks.
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*StackExtMBB) || recomputeLiveIns(*NextMBB);
- } while (anyChange);
+ fullyRecomputeLiveIns({StackExtMBB, NextMBB});
}
bool SystemZXPLINKFrameLowering::hasFP(const MachineFunction &MF) const {
diff --git a/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp
index d914e1b61ab075..4521401d8741c7 100644
--- a/llvm/lib/Target/X86/X86FrameLowering.cpp
+++ b/llvm/lib/Target/X86/X86FrameLowering.cpp
@@ -885,10 +885,7 @@ void X86FrameLowering::emitStackProbeInlineGenericLoop(
}
// Update Live In information
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*tailMBB) || recomputeLiveIns(*testMBB);
- } while (anyChange);
+ fullyRecomputeLiveIns({tailMBB, testMBB});
}
void X86FrameLowering::emitStackProbeInlineWindowsCoreCLR64(
@@ -1380,11 +1377,7 @@ void X86FrameLowering::BuildStackAlignAND(MachineBasicBlock &MBB,
footMBB->addSuccessor(&MBB);
}
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*footMBB) || recomputeLiveIns(*bodyMBB) ||
- recomputeLiveIns(*headMBB) || recomputeLiveIns(MBB);
- } while (anyChange);
+ fullyRecomputeLiveIns({footMBB, bodyMBB, headMBB, &MBB});
}
} else {
MachineInstr *MI = BuildMI(MBB, MBBI, DL, TII.get(AndOp), Reg)
|
|
@llvm/pr-subscribers-backend-arm Author: Kai Nacke (redstar) Changes#79940 put calls to recomputeLiveIns into Note that this changes the order in which recomputeLiveIns is called. For example, only begins to recompute the live-ins for LoopMBB after the computation for ExitMBB Full diff: https://github.com/llvm/llvm-project/pull/88040.diff 9 Files Affected:
diff --git a/llvm/include/llvm/CodeGen/LivePhysRegs.h b/llvm/include/llvm/CodeGen/LivePhysRegs.h
index 1d40b1cbb0eaa3..a2447e7702c77f 100644
--- a/llvm/include/llvm/CodeGen/LivePhysRegs.h
+++ b/llvm/include/llvm/CodeGen/LivePhysRegs.h
@@ -39,6 +39,8 @@
namespace llvm {
+template <typename T> class ArrayRef;
+
class MachineInstr;
class MachineFunction;
class MachineOperand;
@@ -207,6 +209,18 @@ static inline bool recomputeLiveIns(MachineBasicBlock &MBB) {
return oldLiveIns != newLiveIns;
}
+/// Convenience function for recomputing live-in's for a set of MBBs until the
+/// computation converges.
+static inline void
+fullyRecomputeLiveIns(ArrayRef<MachineBasicBlock *> MBBs) {
+ bool AnyChange;
+ do {
+ AnyChange = false;
+ for (MachineBasicBlock *MBB : MBBs)
+ AnyChange = recomputeLiveIns(*MBB) || AnyChange;
+ } while (AnyChange);
+}
+
} // end namespace llvm
#endif // LLVM_CODEGEN_LIVEPHYSREGS_H
diff --git a/llvm/lib/CodeGen/BranchFolding.cpp b/llvm/lib/CodeGen/BranchFolding.cpp
index ecf7bc30913f51..55aa1d438b2a66 100644
--- a/llvm/lib/CodeGen/BranchFolding.cpp
+++ b/llvm/lib/CodeGen/BranchFolding.cpp
@@ -2047,12 +2047,8 @@ bool BranchFolder::HoistCommonCodeInSuccs(MachineBasicBlock *MBB) {
MBB->splice(Loc, TBB, TBB->begin(), TIB);
FBB->erase(FBB->begin(), FIB);
- if (UpdateLiveIns) {
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*TBB) || recomputeLiveIns(*FBB);
- } while (anyChange);
- }
+ if (UpdateLiveIns)
+ fullyRecomputeLiveIns({TBB, FBB});
++NumHoist;
return true;
diff --git a/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp b/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
index 5cc612e89162af..419c141121c325 100644
--- a/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
@@ -4325,10 +4325,7 @@ AArch64FrameLowering::inlineStackProbeLoopExactMultiple(
ExitMBB->transferSuccessorsAndUpdatePHIs(&MBB);
MBB.addSuccessor(LoopMBB);
// Update liveins.
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*ExitMBB) || recomputeLiveIns(*LoopMBB);
- } while (anyChange);
+ fullyRecomputeLiveIns({ExitMBB, LoopMBB});
return ExitMBB->begin();
}
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
index 22687b0e31c284..9f7176694d540a 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -9557,15 +9557,8 @@ AArch64InstrInfo::probedStackAlloc(MachineBasicBlock::iterator MBBI,
MBB.addSuccessor(LoopTestMBB);
// Update liveins.
- if (MF.getRegInfo().reservedRegsFrozen()) {
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*ExitMBB) ||
- recomputeLiveIns(*LoopBodyMBB) ||
- recomputeLiveIns(*LoopTestMBB);
- } while (anyChange);
- ;
- }
+ if (MF.getRegInfo().reservedRegsFrozen())
+ fullyRecomputeLiveIns({ExitMBB, LoopBodyMBB, LoopTestMBB});
return ExitMBB->begin();
}
diff --git a/llvm/lib/Target/ARM/ARMLowOverheadLoops.cpp b/llvm/lib/Target/ARM/ARMLowOverheadLoops.cpp
index 8629551152cb64..ea5dd5427ce720 100644
--- a/llvm/lib/Target/ARM/ARMLowOverheadLoops.cpp
+++ b/llvm/lib/Target/ARM/ARMLowOverheadLoops.cpp
@@ -1806,13 +1806,7 @@ void ARMLowOverheadLoops::Expand(LowOverheadLoop &LoLoop) {
PostOrderLoopTraversal DFS(LoLoop.ML, *MLI);
DFS.ProcessLoop();
const SmallVectorImpl<MachineBasicBlock*> &PostOrder = DFS.getOrder();
- bool anyChange = false;
- do {
- anyChange = false;
- for (auto *MBB : PostOrder) {
- anyChange = recomputeLiveIns(*MBB) || anyChange;
- }
- } while (anyChange);
+ fullyRecomputeLiveIns(PostOrder);
for (auto *MBB : reverse(PostOrder))
recomputeLivenessFlags(*MBB);
diff --git a/llvm/lib/Target/PowerPC/PPCExpandAtomicPseudoInsts.cpp b/llvm/lib/Target/PowerPC/PPCExpandAtomicPseudoInsts.cpp
index b43eee8fdd8c0f..b3cfcb2aa14405 100644
--- a/llvm/lib/Target/PowerPC/PPCExpandAtomicPseudoInsts.cpp
+++ b/llvm/lib/Target/PowerPC/PPCExpandAtomicPseudoInsts.cpp
@@ -208,10 +208,7 @@ bool PPCExpandAtomicPseudo::expandAtomicRMW128(
.addMBB(LoopMBB);
CurrentMBB->addSuccessor(LoopMBB);
CurrentMBB->addSuccessor(ExitMBB);
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*ExitMBB) || recomputeLiveIns(*LoopMBB);
- } while (anyChange);
+ fullyRecomputeLiveIns({ExitMBB, LoopMBB});
NMBBI = MBB.end();
MI.eraseFromParent();
return true;
@@ -288,11 +285,7 @@ bool PPCExpandAtomicPseudo::expandAtomicCmpSwap128(
CurrentMBB->addSuccessor(LoopCmpMBB);
CurrentMBB->addSuccessor(ExitMBB);
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*ExitMBB) || recomputeLiveIns(*CmpSuccMBB) ||
- recomputeLiveIns(*LoopCmpMBB);
- } while (anyChange);
+ fullyRecomputeLiveIns({ExitMBB, CmpSuccMBB, LoopCmpMBB});
NMBBI = MBB.end();
MI.eraseFromParent();
return true;
diff --git a/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp b/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
index 6dcb59a3a57f85..04e9f9e2366edd 100644
--- a/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
@@ -1435,11 +1435,7 @@ void PPCFrameLowering::inlineStackProbe(MachineFunction &MF,
ProbeLoopBodyMBB->addSuccessor(ProbeLoopBodyMBB);
}
// Update liveins.
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*ProbeExitMBB) ||
- recomputeLiveIns(*ProbeLoopBodyMBB);
- } while (anyChange);
+ fullyRecomputeLiveIns({ProbeExitMBB, ProbeLoopBodyMBB});
return ProbeExitMBB;
};
// For case HasBP && MaxAlign > 1, we have to realign the SP by performing
@@ -1531,10 +1527,7 @@ void PPCFrameLowering::inlineStackProbe(MachineFunction &MF,
buildDefCFAReg(*ExitMBB, ExitMBB->begin(), SPReg);
}
// Update liveins.
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*ExitMBB) || recomputeLiveIns(*LoopMBB);
- } while (anyChange);
+ fullyRecomputeLiveIns({ExitMBB, LoopMBB});
}
}
++NumPrologProbed;
diff --git a/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp b/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
index 4897b37d8eb1ef..50ecd6e0744147 100644
--- a/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
@@ -824,10 +824,7 @@ void SystemZELFFrameLowering::inlineStackProbe(
StackAllocMI->eraseFromParent();
if (DoneMBB != nullptr) {
// Compute the live-in lists for the new blocks.
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*DoneMBB) || recomputeLiveIns(*LoopMBB);
- } while (anyChange);
+ fullyRecomputeLiveIns({DoneMBB, LoopMBB});
}
}
@@ -1425,10 +1422,7 @@ void SystemZXPLINKFrameLowering::inlineStackProbe(
StackAllocMI->eraseFromParent();
// Compute the live-in lists for the new blocks.
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*StackExtMBB) || recomputeLiveIns(*NextMBB);
- } while (anyChange);
+ fullyRecomputeLiveIns({StackExtMBB, NextMBB});
}
bool SystemZXPLINKFrameLowering::hasFP(const MachineFunction &MF) const {
diff --git a/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp
index d914e1b61ab075..4521401d8741c7 100644
--- a/llvm/lib/Target/X86/X86FrameLowering.cpp
+++ b/llvm/lib/Target/X86/X86FrameLowering.cpp
@@ -885,10 +885,7 @@ void X86FrameLowering::emitStackProbeInlineGenericLoop(
}
// Update Live In information
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*tailMBB) || recomputeLiveIns(*testMBB);
- } while (anyChange);
+ fullyRecomputeLiveIns({tailMBB, testMBB});
}
void X86FrameLowering::emitStackProbeInlineWindowsCoreCLR64(
@@ -1380,11 +1377,7 @@ void X86FrameLowering::BuildStackAlignAND(MachineBasicBlock &MBB,
footMBB->addSuccessor(&MBB);
}
- bool anyChange = false;
- do {
- anyChange = recomputeLiveIns(*footMBB) || recomputeLiveIns(*bodyMBB) ||
- recomputeLiveIns(*headMBB) || recomputeLiveIns(MBB);
- } while (anyChange);
+ fullyRecomputeLiveIns({footMBB, bodyMBB, headMBB, &MBB});
}
} else {
MachineInstr *MI = BuildMI(MBB, MBBI, DL, TII.get(AndOp), Reg)
|
redstar
requested review from
oskarwirga and
nikic
and removed request for
oskarwirga
You can test this locally with the following command:git-clang-format --diff a9111d4a26514e169ca57c11e6533ca7c5408832 c722f4728e13e22b4896131f5dc0bc8094c09494 -- llvm/include/llvm/CodeGen/LivePhysRegs.h llvm/lib/CodeGen/BranchFolding.cpp llvm/lib/Target/AArch64/AArch64FrameLowering.cpp llvm/lib/Target/AArch64/AArch64InstrInfo.cpp llvm/lib/Target/ARM/ARMLowOverheadLoops.cpp llvm/lib/Target/PowerPC/PPCExpandAtomicPseudoInsts.cpp llvm/lib/Target/PowerPC/PPCFrameLowering.cpp llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp llvm/lib/Target/X86/X86FrameLowering.cppView the diff from clang-format here.diff --git a/llvm/include/llvm/CodeGen/LivePhysRegs.h b/llvm/include/llvm/CodeGen/LivePhysRegs.h
index 9574a6f0c7..ec4ac5947f 100644
--- a/llvm/include/llvm/CodeGen/LivePhysRegs.h
+++ b/llvm/include/llvm/CodeGen/LivePhysRegs.h
@@ -224,7 +224,6 @@ inline void fullyRecomputeLiveIns(ArrayRef<MachineBasicBlock *> MBBs) {
}
}
-
} // end namespace llvm
#endif // LLVM_CODEGEN_LIVEPHYSREGS_H
|
|
My understanding is that the live-ins computation for the basic blocks is independent Also, is the function |
That's what I expect to result in unnecessary calls since once you've computed live-ins for a block, immediately (i.e. without touching a different block) re-computing them for the same block would result in no change (50% waste), except when the block loops into itself, in which case only you get "only" 33.3% waste.
I would suggest to leave it alone, so one can control independently the computation on a block and the order in which those computations are performed (even though DFS order is universally preferred). |
momchil-velikov
approved these changes
Apr 9, 2024
yozhu
reviewed
Apr 9, 2024
| @@ -207,6 +209,18 @@ static inline bool recomputeLiveIns(MachineBasicBlock &MBB) { | |||
| return oldLiveIns != newLiveIns; | |||
| } | |||
|
|
|||
| /// Convenience function for recomputing live-in's for a set of MBBs until the | |||
| /// computation converges. | |||
| static inline void | |||
There was a problem hiding this comment.
This new function doesn't need to be defined as static in the header file.
Good point. I'll try a run. |
oskarwirga
approved these changes
Apr 10, 2024
llvm#79940 put calls to recomputeLiveIns into a loop, to repeatedly call the function until the computation converges. However, this repeats a lot of code. This changes moves the loop into a function to simplify the handling. Note that this changes the order in which recomputeLiveIns is called. For example, ``` bool anyChange = false; do { anyChange = recomputeLiveIns(*ExitMBB) || recomputeLiveIns(*LoopMBB); } while (anyChange); ``` only begins to recompute the live-ins for LoopMBB after the computation for ExitMBB has converged. With this change, all basic blocks have a recomputation of the live-ins for each loop iteration. This can result in less or more calls, depending on the situation.
as suggested by review comment.
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Sorry for the delay, I ran into some trouble with CTMark. Turned out that the commit I based my changes on had a problem. |
|
I removed all the syntactic sugar inside the loop. Now I get the expected result: with this change, clang is faster than the unmodified version (on CTMark). |
yozhu
approved these changes
Apr 15, 2024
aniplcc
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Apr 15, 2024
llvm#79940 put calls to recomputeLiveIns into a loop, to repeatedly call the function until the computation converges. However, this repeats a lot of code. This changes moves the loop into a function to simplify the handling. Note that this changes the order in which recomputeLiveIns is called. For example, ``` bool anyChange = false; do { anyChange = recomputeLiveIns(*ExitMBB) || recomputeLiveIns(*LoopMBB); } while (anyChange); ``` only begins to recompute the live-ins for LoopMBB after the computation for ExitMBB has converged. With this change, all basic blocks have a recomputation of the live-ins for each loop iteration. This can result in less or more calls, depending on the situation.
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#79940 put calls to recomputeLiveIns into
a loop, to repeatedly call the function until the computation converges. However,
this repeats a lot of code. This changes moves the loop into a function to simplify
the handling.
Note that this changes the order in which recomputeLiveIns is called. For example,
only begins to recompute the live-ins for LoopMBB after the computation for ExitMBB
has converged. With this change, all basic blocks have a recomputation of the live-ins
for each loop iteration. This can result in less or more calls, depending on the
situation.