[llvm] [ReachingDefAnalysis] Fix management of MBBFrameObjsReachingDefs (PR #124943)
Michael Maitland via llvm-commits
llvm-commits at lists.llvm.org
Fri Jan 31 10:50:47 PST 2025
https://github.com/michaelmaitland updated https://github.com/llvm/llvm-project/pull/124943
>From f14a174452c752f5027929d66a6d6d31bb8d9cae Mon Sep 17 00:00:00 2001
From: Michael Maitland <michaeltmaitland at gmail.com>
Date: Thu, 30 Jan 2025 07:20:05 -0800
Subject: [PATCH 1/3] precommit test case
---
llvm/test/CodeGen/RISCV/rda-stack.mir | 37 +++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/llvm/test/CodeGen/RISCV/rda-stack.mir b/llvm/test/CodeGen/RISCV/rda-stack.mir
index 5f4974181c1cd5..fc5bd8acd2840a 100644
--- a/llvm/test/CodeGen/RISCV/rda-stack.mir
+++ b/llvm/test/CodeGen/RISCV/rda-stack.mir
@@ -149,3 +149,40 @@ body: |
$x10 = LD %stack.0, 0 :: (load (s64))
PseudoRET implicit $x10
...
+---
+name: test4
+tracksRegLiveness: true
+stack:
+ - { id: 0, name: '', type: default, offset: 0, size: 4, alignment: 4,
+ stack-id: default, callee-saved-register: '', callee-saved-restored: true,
+ debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+ - { id: 1, name: '', type: default, offset: 0, size: 4, alignment: 4,
+ stack-id: default, callee-saved-register: '', callee-saved-restored: true,
+ debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+body: |
+ ; CHECK: RDA results for test4
+ ; CHECK-NEXT: $x10:{ }
+ ; CHECK-NEXT: %stack.0:{ }
+ ; CHECK-NEXT: 0: SD $x10, %stack.0, 0 :: (store (s64))
+ ; CHECK-EMPTY:
+ ; CHECK-NEXT: $x11:{ }
+ ; CHECK-NEXT: %stack.0:{ 0 }
+ ; CHECK-NEXT: 1: SD $x11, %stack.0, 0 :: (store (s64))
+ ; CHECK-EMPTY:
+ ; CHECK-NEXT: $x10:{ }
+ ; CHECK-NEXT: %stack.1:{ }
+ ; CHECK-NEXT: 2: SD $x10, %stack.1, 0 :: (store (s64))
+ ; CHECK-EMPTY:
+ ; CHECK-NEXT: $x11:{ }
+ ; CHECK-NEXT: %stack.1:{ }
+ ; CHECK-NEXT: 3: SD $x11, %stack.1, 0 :: (store (s64))
+ ; CHECK-EMPTY:
+ ; CHECK-NEXT: 4: PseudoRET
+ bb.0.entry:
+ liveins: $x10, $x11
+ SD $x10, %stack.0, 0 :: (store (s64))
+ SD $x11, %stack.0, 0 :: (store (s64))
+ SD $x10, %stack.1, 0 :: (store (s64))
+ SD $x11, %stack.1, 0 :: (store (s64))
+ PseudoRET
+...
>From af0058bf5257908b181c00f25b7528ac7ea3b32c Mon Sep 17 00:00:00 2001
From: Michael Maitland <michaeltmaitland at gmail.com>
Date: Wed, 29 Jan 2025 08:39:09 -0800
Subject: [PATCH 2/3] [ReachingDefAnalysis][NFC] Fix management of
MBBFrameObjsReachingDefs
---
llvm/lib/CodeGen/ReachingDefAnalysis.cpp | 28 ++++++++++++++----------
llvm/test/CodeGen/RISCV/rda-stack.mir | 2 +-
2 files changed, 17 insertions(+), 13 deletions(-)
diff --git a/llvm/lib/CodeGen/ReachingDefAnalysis.cpp b/llvm/lib/CodeGen/ReachingDefAnalysis.cpp
index 08121f411640c8..a2adc5ede28890 100644
--- a/llvm/lib/CodeGen/ReachingDefAnalysis.cpp
+++ b/llvm/lib/CodeGen/ReachingDefAnalysis.cpp
@@ -147,16 +147,9 @@ void ReachingDefAnalysis::processDefs(MachineInstr *MI) {
assert(FrameIndex >= 0 && "Can't handle negative frame indicies yet!");
if (!isFIDef(*MI, FrameIndex, TII))
continue;
- if (MBBFrameObjsReachingDefs.contains(MBBNumber)) {
- auto Frame2InstrIdx = MBBFrameObjsReachingDefs[MBBNumber];
- if (Frame2InstrIdx.count(FrameIndex - ObjectIndexBegin) > 0)
- Frame2InstrIdx[FrameIndex - ObjectIndexBegin].push_back(CurInstr);
- else
- Frame2InstrIdx[FrameIndex - ObjectIndexBegin] = {CurInstr};
- } else {
- MBBFrameObjsReachingDefs[MBBNumber] = {
- {FrameIndex - ObjectIndexBegin, {CurInstr}}};
- }
+
+ int Key = FrameIndex - ObjectIndexBegin;
+ MBBFrameObjsReachingDefs[MBBNumber][Key].push_back(CurInstr);
}
if (!isValidRegDef(MO))
continue;
@@ -348,8 +341,19 @@ int ReachingDefAnalysis::getReachingDef(MachineInstr *MI, Register Reg) const {
if (Reg.isStack()) {
int FrameIndex = Reg.stackSlotIndex();
- for (int Def : MBBFrameObjsReachingDefs.lookup(MBBNumber).lookup(
- FrameIndex - ObjectIndexBegin)) {
+ int Key = FrameIndex - ObjectIndexBegin;
+
+ // Check that there was a reaching def.
+ auto Lookup1 = MBBFrameObjsReachingDefs.find(MBBNumber);
+ if (Lookup1 == MBBFrameObjsReachingDefs.end())
+ return LatestDef;
+ auto &InnerMap = Lookup1->second;
+ auto Lookup2 = InnerMap.find(Key);
+ if (Lookup2 == InnerMap.end())
+ return LatestDef;
+ auto &Defs = Lookup2->second;
+
+ for (int Def : Defs) {
if (Def >= InstId)
break;
DefRes = Def;
diff --git a/llvm/test/CodeGen/RISCV/rda-stack.mir b/llvm/test/CodeGen/RISCV/rda-stack.mir
index fc5bd8acd2840a..3ec17615fa6776 100644
--- a/llvm/test/CodeGen/RISCV/rda-stack.mir
+++ b/llvm/test/CodeGen/RISCV/rda-stack.mir
@@ -174,7 +174,7 @@ body: |
; CHECK-NEXT: 2: SD $x10, %stack.1, 0 :: (store (s64))
; CHECK-EMPTY:
; CHECK-NEXT: $x11:{ }
- ; CHECK-NEXT: %stack.1:{ }
+ ; CHECK-NEXT: %stack.1:{ 2 }
; CHECK-NEXT: 3: SD $x11, %stack.1, 0 :: (store (s64))
; CHECK-EMPTY:
; CHECK-NEXT: 4: PseudoRET
>From eab7c390ac474ae14c9a325cc426f6b43d9066dd Mon Sep 17 00:00:00 2001
From: Michael Maitland <michaeltmaitland at gmail.com>
Date: Fri, 31 Jan 2025 10:46:08 -0800
Subject: [PATCH 3/3] fixup! use FrameIndex as key; simplify map
---
llvm/include/llvm/CodeGen/ReachingDefAnalysis.h | 10 +++++-----
llvm/lib/CodeGen/ReachingDefAnalysis.cpp | 15 ++++-----------
2 files changed, 9 insertions(+), 16 deletions(-)
diff --git a/llvm/include/llvm/CodeGen/ReachingDefAnalysis.h b/llvm/include/llvm/CodeGen/ReachingDefAnalysis.h
index cff422f539f62d..978e84b09a7368 100644
--- a/llvm/include/llvm/CodeGen/ReachingDefAnalysis.h
+++ b/llvm/include/llvm/CodeGen/ReachingDefAnalysis.h
@@ -141,12 +141,12 @@ class ReachingDefAnalysis : public MachineFunctionPass {
DenseMap<MachineInstr *, int> InstIds;
MBBReachingDefsInfo MBBReachingDefs;
+
+ /// MBBFrameObjsReachingDefs[{i, j}] is a list of instruction indices
+ /// (relative to begining of MBB i) that define frame index j in MBB i. This
+ /// is used in answering reaching definition queries.
using MBBFrameObjsReachingDefsInfo =
- DenseMap<unsigned, DenseMap<int, SmallVector<int>>>;
- // MBBFrameObjsReachingDefs[i][j] is a list of instruction indices (relative
- // to begining of MBB) that define frame index (j +
- // MF->getFrameInfo().getObjectIndexBegin()) in MBB i. This is used in
- // answering reaching definition queries.
+ DenseMap<std::pair<unsigned, int>, SmallVector<int>>;
MBBFrameObjsReachingDefsInfo MBBFrameObjsReachingDefs;
/// Default values are 'nothing happened a long time ago'.
diff --git a/llvm/lib/CodeGen/ReachingDefAnalysis.cpp b/llvm/lib/CodeGen/ReachingDefAnalysis.cpp
index a2adc5ede28890..1dd051814c36d6 100644
--- a/llvm/lib/CodeGen/ReachingDefAnalysis.cpp
+++ b/llvm/lib/CodeGen/ReachingDefAnalysis.cpp
@@ -147,9 +147,7 @@ void ReachingDefAnalysis::processDefs(MachineInstr *MI) {
assert(FrameIndex >= 0 && "Can't handle negative frame indicies yet!");
if (!isFIDef(*MI, FrameIndex, TII))
continue;
-
- int Key = FrameIndex - ObjectIndexBegin;
- MBBFrameObjsReachingDefs[MBBNumber][Key].push_back(CurInstr);
+ MBBFrameObjsReachingDefs[{MBBNumber, FrameIndex}].push_back(CurInstr);
}
if (!isValidRegDef(MO))
continue;
@@ -344,15 +342,10 @@ int ReachingDefAnalysis::getReachingDef(MachineInstr *MI, Register Reg) const {
int Key = FrameIndex - ObjectIndexBegin;
// Check that there was a reaching def.
- auto Lookup1 = MBBFrameObjsReachingDefs.find(MBBNumber);
- if (Lookup1 == MBBFrameObjsReachingDefs.end())
- return LatestDef;
- auto &InnerMap = Lookup1->second;
- auto Lookup2 = InnerMap.find(Key);
- if (Lookup2 == InnerMap.end())
+ auto Lookup = MBBFrameObjsReachingDefs.find({MBBNumber, Key});
+ if (Lookup == MBBFrameObjsReachingDefs.end())
return LatestDef;
- auto &Defs = Lookup2->second;
-
+ auto &Defs = Lookup->second;
for (int Def : Defs) {
if (Def >= InstId)
break;
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