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[MachineCopyPropagation][RISCV] Fix D125335 accidentally change control flow. 

D125335 makes regsOverlap skip following control flow, which is not entended
in the original code.

Differential Revision: https://reviews.llvm.org/D128039
This commit is contained in:
Han-Kuan Chen 2022-06-17 01:34:17 -07:00
parent dbfb00a930
commit e29133629b
2 changed files with 84 additions and 86 deletions
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162
llvm/lib/CodeGen/MachineCopyPropagation.cpp
View File

@ -660,77 +660,76 @@ void MachineCopyPropagation::ForwardCopyPropagateBlock(MachineBasicBlock &MBB) {
Register RegSrc = CopyOperands->Source->getReg();
Register RegDef = CopyOperands->Destination->getReg();
if (TRI->regsOverlap(RegDef, RegSrc))
if (!TRI->regsOverlap(RegDef, RegSrc)) {
assert(RegDef.isPhysical() && RegSrc.isPhysical() &&
"MachineCopyPropagation should be run after register allocation!");
MCRegister Def = RegDef.asMCReg();
MCRegister Src = RegSrc.asMCReg();
// The two copies cancel out and the source of the first copy
// hasn't been overridden, eliminate the second one. e.g.
// %ecx = COPY %eax
// ... nothing clobbered eax.
// %eax = COPY %ecx
// =>
// %ecx = COPY %eax
//
// or
//
// %ecx = COPY %eax
// ... nothing clobbered eax.
// %ecx = COPY %eax
// =>
// %ecx = COPY %eax
if (eraseIfRedundant(MI, Def, Src) || eraseIfRedundant(MI, Src, Def))
continue;
forwardUses(MI);
// Src may have been changed by forwardUses()
CopyOperands = isCopyInstr(MI, *TII, UseCopyInstr);
Src = CopyOperands->Source->getReg().asMCReg();
// If Src is defined by a previous copy, the previous copy cannot be
// eliminated.
ReadRegister(Src, MI, RegularUse);
for (const MachineOperand &MO : MI.implicit_operands()) {
if (!MO.isReg() || !MO.readsReg())
continue;
MCRegister Reg = MO.getReg().asMCReg();
if (!Reg)
continue;
ReadRegister(Reg, MI, RegularUse);
}
LLVM_DEBUG(dbgs() << "MCP: Copy is a deletion candidate: "; MI.dump());
// Copy is now a candidate for deletion.
if (!MRI->isReserved(Def))
MaybeDeadCopies.insert(&MI);
// If 'Def' is previously source of another copy, then this earlier copy's
// source is no longer available. e.g.
// %xmm9 = copy %xmm2
// ...
// %xmm2 = copy %xmm0
// ...
// %xmm2 = copy %xmm9
Tracker.clobberRegister(Def, *TRI, *TII, UseCopyInstr);
for (const MachineOperand &MO : MI.implicit_operands()) {
if (!MO.isReg() || !MO.isDef())
continue;
MCRegister Reg = MO.getReg().asMCReg();
if (!Reg)
continue;
Tracker.clobberRegister(Reg, *TRI, *TII, UseCopyInstr);
}
Tracker.trackCopy(&MI, *TRI, *TII, UseCopyInstr);
continue;
assert(RegDef.isPhysical() && RegSrc.isPhysical() &&
"MachineCopyPropagation should be run after register allocation!");
MCRegister Def = RegDef.asMCReg();
MCRegister Src = RegSrc.asMCReg();
// The two copies cancel out and the source of the first copy
// hasn't been overridden, eliminate the second one. e.g.
// %ecx = COPY %eax
// ... nothing clobbered eax.
// %eax = COPY %ecx
// =>
// %ecx = COPY %eax
//
// or
//
// %ecx = COPY %eax
// ... nothing clobbered eax.
// %ecx = COPY %eax
// =>
// %ecx = COPY %eax
if (eraseIfRedundant(MI, Def, Src) || eraseIfRedundant(MI, Src, Def))
continue;
forwardUses(MI);
// Src may have been changed by forwardUses()
CopyOperands = isCopyInstr(MI, *TII, UseCopyInstr);
Src = CopyOperands->Source->getReg().asMCReg();
// If Src is defined by a previous copy, the previous copy cannot be
// eliminated.
ReadRegister(Src, MI, RegularUse);
for (const MachineOperand &MO : MI.implicit_operands()) {
if (!MO.isReg() || !MO.readsReg())
continue;
MCRegister Reg = MO.getReg().asMCReg();
if (!Reg)
continue;
ReadRegister(Reg, MI, RegularUse);
}
LLVM_DEBUG(dbgs() << "MCP: Copy is a deletion candidate: "; MI.dump());
// Copy is now a candidate for deletion.
if (!MRI->isReserved(Def))
MaybeDeadCopies.insert(&MI);
// If 'Def' is previously source of another copy, then this earlier copy's
// source is no longer available. e.g.
// %xmm9 = copy %xmm2
// ...
// %xmm2 = copy %xmm0
// ...
// %xmm2 = copy %xmm9
Tracker.clobberRegister(Def, *TRI, *TII, UseCopyInstr);
for (const MachineOperand &MO : MI.implicit_operands()) {
if (!MO.isReg() || !MO.isDef())
continue;
MCRegister Reg = MO.getReg().asMCReg();
if (!Reg)
continue;
Tracker.clobberRegister(Reg, *TRI, *TII, UseCopyInstr);
}
Tracker.trackCopy(&MI, *TRI, *TII, UseCopyInstr);
continue;
}
// Clobber any earlyclobber regs first.
@ -927,23 +926,22 @@ void MachineCopyPropagation::BackwardCopyPropagateBlock(
for (MachineInstr &MI : llvm::make_early_inc_range(llvm::reverse(MBB))) {
// Ignore non-trivial COPYs.
Optional<DestSourcePair> CopyOperands = isCopyInstr(MI, *TII, UseCopyInstr);
if (CopyOperands) {
if (CopyOperands && MI.getNumOperands() == 2) {
Register DefReg = CopyOperands->Destination->getReg();
Register SrcReg = CopyOperands->Source->getReg();
if (TRI->regsOverlap(DefReg, SrcReg))
continue;
if (!TRI->regsOverlap(DefReg, SrcReg)) {
MCRegister Def = DefReg.asMCReg();
MCRegister Src = SrcReg.asMCReg();
MCRegister Def = DefReg.asMCReg();
MCRegister Src = SrcReg.asMCReg();
// Unlike forward cp, we don't invoke propagateDefs here,
// just let forward cp do COPY-to-COPY propagation.
if (isBackwardPropagatableCopy(MI, *MRI, *TII, UseCopyInstr)) {
Tracker.invalidateRegister(Src, *TRI, *TII, UseCopyInstr);
Tracker.invalidateRegister(Def, *TRI, *TII, UseCopyInstr);
Tracker.trackCopy(&MI, *TRI, *TII, UseCopyInstr);
continue;
// Unlike forward cp, we don't invoke propagateDefs here,
// just let forward cp do COPY-to-COPY propagation.
if (isBackwardPropagatableCopy(MI, *MRI, *TII, UseCopyInstr)) {
Tracker.invalidateRegister(Src, *TRI, *TII, UseCopyInstr);
Tracker.invalidateRegister(Def, *TRI, *TII, UseCopyInstr);
Tracker.trackCopy(&MI, *TRI, *TII, UseCopyInstr);
continue;
}
}
}

8
llvm/test/CodeGen/RISCV/machine-cp.mir
View File

@ -18,14 +18,14 @@ body: |
; RV32-LABEL: name: foo
; RV32: liveins: $v28_v29_v30, $v8_v9, $v1
; RV32-NEXT: {{ $}}
; RV32-NEXT: renamable $v4_v5_v6_v7_v8_v9_v10_v11 = COPY renamable $v0_v1_v2_v3_v4_v5_v6_v7
; RV32-NEXT: renamable $v28 = COPY $v1, implicit killed $v28_v29_v30, implicit-def $v28_v29_v30
; RV32-NEXT: renamable $v4_v5_v6_v7_v8_v9_v10_v11 = COPY killed renamable $v0_v1_v2_v3_v4_v5_v6_v7
; RV32-NEXT: renamable $v28 = COPY renamable $v8, implicit killed $v28_v29_v30, implicit-def $v28_v29_v30
; RV32-NEXT: PseudoRET implicit $v28
; RV64-LABEL: name: foo
; RV64: liveins: $v28_v29_v30, $v8_v9, $v1
; RV64-NEXT: {{ $}}
; RV64-NEXT: renamable $v4_v5_v6_v7_v8_v9_v10_v11 = COPY renamable $v0_v1_v2_v3_v4_v5_v6_v7
; RV64-NEXT: renamable $v28 = COPY $v1, implicit killed $v28_v29_v30, implicit-def $v28_v29_v30
; RV64-NEXT: renamable $v4_v5_v6_v7_v8_v9_v10_v11 = COPY killed renamable $v0_v1_v2_v3_v4_v5_v6_v7
; RV64-NEXT: renamable $v28 = COPY renamable $v8, implicit killed $v28_v29_v30, implicit-def $v28_v29_v30
; RV64-NEXT: PseudoRET implicit $v28
renamable $v8 = COPY renamable $v1, implicit killed $v8_v9, implicit-def $v8_v9
renamable $v4_v5_v6_v7_v8_v9_v10_v11 = COPY killed renamable $v0_v1_v2_v3_v4_v5_v6_v7