[llvm] [RegisterCoalescer] Deferring deletion of instructions in `ErasedInstrs` until the end of an iteration (PR #79820)
Quentin Dian via llvm-commits
llvm-commits at lists.llvm.org
Thu Feb 8 04:42:24 PST 2024
https://github.com/DianQK updated https://github.com/llvm/llvm-project/pull/79820
>From 646c95f6169fa556a725ed9e3bb93be557499cbb Mon Sep 17 00:00:00 2001
From: DianQK <dianqk at dianqk.net>
Date: Thu, 8 Feb 2024 20:40:02 +0800
Subject: [PATCH 1/2] Pre-commit test cases
---
.../register-coalescer-crash-pr79718.mir | 128 ++++++++++++++++++
1 file changed, 128 insertions(+)
create mode 100644 llvm/test/CodeGen/LoongArch/register-coalescer-crash-pr79718.mir
diff --git a/llvm/test/CodeGen/LoongArch/register-coalescer-crash-pr79718.mir b/llvm/test/CodeGen/LoongArch/register-coalescer-crash-pr79718.mir
new file mode 100644
index 0000000000000..dab679c6250b7
--- /dev/null
+++ b/llvm/test/CodeGen/LoongArch/register-coalescer-crash-pr79718.mir
@@ -0,0 +1,128 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 4
+# RUN: llc -o - %s -mtriple=loongarch64 \
+# RUN: -run-pass=register-coalescer -join-liveintervals=1 -join-splitedges=0 2>&1 | FileCheck %s
+
+---
+name: foo
+tracksRegLiveness: true
+body: |
+ bb.0:
+ liveins: $r4, $r5, $r6, $r7, $r8
+
+ %22:gpr = COPY killed $r8
+ %21:gpr = COPY killed $r7
+ %20:gpr = COPY killed $r6
+ %19:gpr = COPY killed $r5
+ %18:gpr = COPY killed $r4
+ %29:gpr = COPY $r0
+ %27:gpr = COPY killed %29
+ %30:gpr = ANDI killed %19, 1
+ %41:gpr = ORI $r0, 1
+ %35:gpr = ANDI killed %20, 1
+ %36:gpr = ANDI killed %21, 1
+ %39:gpr = ANDI killed %22, 1
+ %43:gpr = COPY %27
+ %44:gpr = COPY killed %27
+ %45:gpr = IMPLICIT_DEF
+
+ bb.1:
+ %2:gpr = COPY killed %45
+ %1:gpr = COPY killed %44
+ %0:gpr = COPY killed %43
+ %46:gpr = COPY %0
+ %47:gpr = COPY %1
+ %48:gpr = COPY killed %1
+ %49:gpr = COPY killed %2
+
+ bb.2:
+ successors: %bb.3, %bb.4
+
+ %6:gpr = COPY killed %49
+ %5:gpr = COPY killed %48
+ %4:gpr = COPY killed %47
+ %3:gpr = COPY killed %46
+ BEQZ %30, %bb.4
+
+ bb.3:
+ %51:gpr = COPY killed %4
+ %52:gpr = COPY killed %5
+ PseudoBR %bb.9
+
+ bb.4:
+ %50:gpr = COPY killed %5
+
+ bb.5:
+ successors: %bb.7(0x7c000000), %bb.6(0x04000000)
+
+ %7:gpr = COPY killed %50
+ dead %33:gpr = LD_D $r0, 8
+ dead %34:gpr = LD_D $r0, 0
+ BNEZ %35, %bb.7
+
+ bb.6:
+ %32:gpr = COPY $r0
+ %31:gpr = COPY killed %32
+ %53:gpr = COPY killed %31
+ %54:gpr = COPY killed %6
+ PseudoBR %bb.11
+
+ bb.7:
+ successors: %bb.8(0x7c000000), %bb.10(0x04000000)
+
+ BEQZ %36, %bb.10
+ PseudoBR %bb.8
+
+ bb.8:
+ successors: %bb.9(0x04000000), %bb.5(0x7c000000)
+
+ %8:gpr = ADDI_D killed %7, 1
+ %50:gpr = COPY %8
+ %51:gpr = COPY %8
+ %52:gpr = COPY killed %8
+ BEQZ %39, %bb.5
+ PseudoBR %bb.9
+
+ bb.9:
+ %10:gpr = COPY killed %52
+ %9:gpr = COPY killed %51
+ %40:gpr = COPY $r0
+ ST_B killed %40, %18, 0
+ %55:gpr = COPY killed %3
+ %56:gpr = COPY killed %9
+ %57:gpr = COPY killed %10
+ %58:gpr = COPY killed %6
+ PseudoBR %bb.12
+
+ bb.10:
+ %42:gpr = ADDI_D killed %7, 1
+ %53:gpr = COPY %41
+ %54:gpr = COPY killed %42
+
+ bb.11:
+ %13:gpr = COPY killed %54
+ %12:gpr = COPY killed %53
+ %38:gpr = COPY $r0
+ ST_D killed %38, %18, 0
+ %55:gpr = COPY %13
+ %56:gpr = COPY %12
+ %57:gpr = COPY killed %12
+ %58:gpr = COPY killed %13
+
+ bb.12:
+ successors: %bb.2(0x7c000000), %bb.1(0x04000000)
+
+ %17:gpr = COPY killed %58
+ %16:gpr = COPY killed %57
+ %15:gpr = COPY killed %56
+ %14:gpr = COPY killed %55
+ %43:gpr = COPY %14
+ %44:gpr = COPY %15
+ %45:gpr = COPY %17
+ %46:gpr = COPY killed %14
+ %47:gpr = COPY killed %15
+ %48:gpr = COPY killed %16
+ %49:gpr = COPY killed %17
+ BEQ %0, %41, %bb.2
+ PseudoBR %bb.1
+
+...
>From 00254d3d7ab40863106af64ee5ba825424e3271d Mon Sep 17 00:00:00 2001
From: DianQK <dianqk at dianqk.net>
Date: Thu, 8 Feb 2024 20:42:12 +0800
Subject: [PATCH 2/2] [RegisterCoalescer] Deferring deletion of instructions in
ErasedInstrs until the end of an iteration
---
llvm/lib/CodeGen/RegisterCoalescer.cpp | 16 ++--
.../register-coalescer-crash-pr79718.mir | 87 ++++++++++++++++++-
2 files changed, 97 insertions(+), 6 deletions(-)
diff --git a/llvm/lib/CodeGen/RegisterCoalescer.cpp b/llvm/lib/CodeGen/RegisterCoalescer.cpp
index cbb1a74049fbd..d3125fba67206 100644
--- a/llvm/lib/CodeGen/RegisterCoalescer.cpp
+++ b/llvm/lib/CodeGen/RegisterCoalescer.cpp
@@ -236,7 +236,8 @@ namespace {
/// was successfully coalesced away. If it is not currently possible to
/// coalesce this interval, but it may be possible if other things get
/// coalesced, then it returns true by reference in 'Again'.
- bool joinCopy(MachineInstr *CopyMI, bool &Again);
+ bool joinCopy(MachineInstr *CopyMI, bool &Again,
+ SmallPtrSetImpl<MachineInstr *> &CurrentErasedInstrs);
/// Attempt to join these two intervals. On failure, this
/// returns false. The output "SrcInt" will not have been modified, so we
@@ -1964,7 +1965,9 @@ void RegisterCoalescer::setUndefOnPrunedSubRegUses(LiveInterval &LI,
LIS->shrinkToUses(&LI);
}
-bool RegisterCoalescer::joinCopy(MachineInstr *CopyMI, bool &Again) {
+bool RegisterCoalescer::joinCopy(
+ MachineInstr *CopyMI, bool &Again,
+ SmallPtrSetImpl<MachineInstr *> &CurrentErasedInstrs) {
Again = false;
LLVM_DEBUG(dbgs() << LIS->getInstructionIndex(*CopyMI) << '\t' << *CopyMI);
@@ -2156,7 +2159,9 @@ bool RegisterCoalescer::joinCopy(MachineInstr *CopyMI, bool &Again) {
// CopyMI has been erased by joinIntervals at this point. Remove it from
// ErasedInstrs since copyCoalesceWorkList() won't add a successful join back
// to the work list. This keeps ErasedInstrs from growing needlessly.
- ErasedInstrs.erase(CopyMI);
+ if (ErasedInstrs.erase(CopyMI))
+ // But we may encounter the instruction again in this iteration.
+ CurrentErasedInstrs.insert(CopyMI);
// Rewrite all SrcReg operands to DstReg.
// Also update DstReg operands to include DstIdx if it is set.
@@ -3982,17 +3987,18 @@ void RegisterCoalescer::lateLiveIntervalUpdate() {
bool RegisterCoalescer::
copyCoalesceWorkList(MutableArrayRef<MachineInstr*> CurrList) {
bool Progress = false;
+ SmallPtrSet<MachineInstr *, 4> CurrentErasedInstrs;
for (MachineInstr *&MI : CurrList) {
if (!MI)
continue;
// Skip instruction pointers that have already been erased, for example by
// dead code elimination.
- if (ErasedInstrs.count(MI)) {
+ if (ErasedInstrs.count(MI) || CurrentErasedInstrs.count(MI)) {
MI = nullptr;
continue;
}
bool Again = false;
- bool Success = joinCopy(MI, Again);
+ bool Success = joinCopy(MI, Again, CurrentErasedInstrs);
Progress |= Success;
if (Success || !Again)
MI = nullptr;
diff --git a/llvm/test/CodeGen/LoongArch/register-coalescer-crash-pr79718.mir b/llvm/test/CodeGen/LoongArch/register-coalescer-crash-pr79718.mir
index dab679c6250b7..bfa8aba55dbc9 100644
--- a/llvm/test/CodeGen/LoongArch/register-coalescer-crash-pr79718.mir
+++ b/llvm/test/CodeGen/LoongArch/register-coalescer-crash-pr79718.mir
@@ -1,11 +1,96 @@
# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 4
# RUN: llc -o - %s -mtriple=loongarch64 \
-# RUN: -run-pass=register-coalescer -join-liveintervals=1 -join-splitedges=0 2>&1 | FileCheck %s
+# RUN: -run-pass=register-coalescer -join-liveintervals=1 -join-splitedges=0 | FileCheck %s
---
name: foo
tracksRegLiveness: true
body: |
+ ; CHECK-LABEL: name: foo
+ ; CHECK: bb.0:
+ ; CHECK-NEXT: successors: %bb.1(0x80000000)
+ ; CHECK-NEXT: liveins: $r4, $r5, $r6, $r7, $r8
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: [[COPY:%[0-9]+]]:gpr = COPY $r8
+ ; CHECK-NEXT: [[COPY1:%[0-9]+]]:gpr = COPY $r7
+ ; CHECK-NEXT: [[COPY2:%[0-9]+]]:gpr = COPY $r6
+ ; CHECK-NEXT: [[COPY3:%[0-9]+]]:gpr = COPY $r5
+ ; CHECK-NEXT: [[COPY4:%[0-9]+]]:gpr = COPY $r4
+ ; CHECK-NEXT: [[ANDI:%[0-9]+]]:gpr = ANDI [[COPY3]], 1
+ ; CHECK-NEXT: [[ORI:%[0-9]+]]:gpr = ORI $r0, 1
+ ; CHECK-NEXT: [[ANDI1:%[0-9]+]]:gpr = ANDI [[COPY2]], 1
+ ; CHECK-NEXT: [[ANDI2:%[0-9]+]]:gpr = ANDI [[COPY1]], 1
+ ; CHECK-NEXT: [[ANDI3:%[0-9]+]]:gpr = ANDI [[COPY]], 1
+ ; CHECK-NEXT: [[COPY5:%[0-9]+]]:gpr = COPY $r0
+ ; CHECK-NEXT: [[COPY6:%[0-9]+]]:gpr = COPY $r0
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: bb.1:
+ ; CHECK-NEXT: successors: %bb.2(0x80000000)
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: [[COPY7:%[0-9]+]]:gpr = COPY [[COPY5]]
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: bb.2:
+ ; CHECK-NEXT: successors: %bb.3(0x40000000), %bb.4(0x40000000)
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: BEQZ [[ANDI]], %bb.4
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: bb.3:
+ ; CHECK-NEXT: successors: %bb.9(0x80000000)
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: PseudoBR %bb.9
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: bb.4:
+ ; CHECK-NEXT: successors: %bb.5(0x80000000)
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: bb.5:
+ ; CHECK-NEXT: successors: %bb.7(0x7c000000), %bb.6(0x04000000)
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: dead [[LD_D:%[0-9]+]]:gpr = LD_D $r0, 8
+ ; CHECK-NEXT: dead [[LD_D1:%[0-9]+]]:gpr = LD_D $r0, 0
+ ; CHECK-NEXT: BNEZ [[ANDI1]], %bb.7
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: bb.6:
+ ; CHECK-NEXT: successors: %bb.11(0x80000000)
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: [[COPY6:%[0-9]+]]:gpr = COPY $r0
+ ; CHECK-NEXT: PseudoBR %bb.11
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: bb.7:
+ ; CHECK-NEXT: successors: %bb.8(0x7c000000), %bb.10(0x04000000)
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: BEQZ [[ANDI2]], %bb.10
+ ; CHECK-NEXT: PseudoBR %bb.8
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: bb.8:
+ ; CHECK-NEXT: successors: %bb.9(0x04000000), %bb.5(0x7c000000)
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: [[COPY6:%[0-9]+]]:gpr = ADDI_D [[COPY6]], 1
+ ; CHECK-NEXT: BEQZ [[ANDI3]], %bb.5
+ ; CHECK-NEXT: PseudoBR %bb.9
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: bb.9:
+ ; CHECK-NEXT: successors: %bb.12(0x80000000)
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: ST_B $r0, [[COPY4]], 0
+ ; CHECK-NEXT: PseudoBR %bb.12
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: bb.10:
+ ; CHECK-NEXT: successors: %bb.11(0x80000000)
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: [[COPY5:%[0-9]+]]:gpr = ADDI_D [[COPY6]], 1
+ ; CHECK-NEXT: [[COPY6:%[0-9]+]]:gpr = COPY [[ORI]]
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: bb.11:
+ ; CHECK-NEXT: successors: %bb.12(0x80000000)
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: ST_D $r0, [[COPY4]], 0
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: bb.12:
+ ; CHECK-NEXT: successors: %bb.2(0x7c000000), %bb.1(0x04000000)
+ ; CHECK-NEXT: {{ $}}
+ ; CHECK-NEXT: BEQ [[COPY7]], [[ORI]], %bb.2
+ ; CHECK-NEXT: PseudoBR %bb.1
bb.0:
liveins: $r4, $r5, $r6, $r7, $r8
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