[llvm] 08b306d - [StackColoring] Delete dead stack slots (#75351)
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Fri Dec 15 01:58:24 PST 2023
Author: mohammed-nurulhoque
Date: 2023-12-15T09:58:19Z
New Revision: 08b306dc8e7c0b2498f4f194a3c51686d56dbd20
URL: https://github.com/llvm/llvm-project/commit/08b306dc8e7c0b2498f4f194a3c51686d56dbd20
DIFF: https://github.com/llvm/llvm-project/commit/08b306dc8e7c0b2498f4f194a3c51686d56dbd20.diff
LOG: [StackColoring] Delete dead stack slots (#75351)
deletes slots that have lifetime markers and the lifetime ranges are empty.
Added:
llvm/test/CodeGen/RISCV/dead-stack-slot.ll
Modified:
llvm/lib/CodeGen/StackColoring.cpp
llvm/test/CodeGen/PowerPC/aix32-cc-abi-vaarg.ll
llvm/test/CodeGen/PowerPC/aix64-cc-abi-vaarg.ll
llvm/test/CodeGen/X86/StackColoring-tbaa.mir
llvm/test/DebugInfo/COFF/lexicalblock.ll
Removed:
################################################################################
diff --git a/llvm/lib/CodeGen/StackColoring.cpp b/llvm/lib/CodeGen/StackColoring.cpp
index 37f7aa9290054e..fa01aa17b3a867 100644
--- a/llvm/lib/CodeGen/StackColoring.cpp
+++ b/llvm/lib/CodeGen/StackColoring.cpp
@@ -900,6 +900,15 @@ void StackColoring::remapInstructions(DenseMap<int, int> &SlotRemap) {
unsigned FixedMemOp = 0;
unsigned FixedDbg = 0;
+ // Remove debug information for deleted slots.
+ erase_if(MF->getVariableDbgInfo(), [&](auto &VI) {
+ if (!VI.inStackSlot())
+ return false;
+ int Slot = VI.getStackSlot();
+ return Slot >= 0 && Intervals[Slot]->empty() &&
+ InterestingSlots.test(Slot) && !ConservativeSlots.test(Slot);
+ });
+
// Remap debug information that refers to stack slots.
for (auto &VI : MF->getVariableDbgInfo()) {
if (!VI.Var || !VI.inStackSlot())
@@ -1250,8 +1259,15 @@ bool StackColoring::runOnMachineFunction(MachineFunction &Func) {
// Do not bother looking at empty intervals.
for (unsigned I = 0; I < NumSlots; ++I) {
- if (Intervals[SortedSlots[I]]->empty())
+ int Slot = SortedSlots[I];
+ if (Intervals[Slot]->empty()) {
+ if (InterestingSlots.test(Slot) && !ConservativeSlots.test(Slot)) {
+ RemovedSlots += 1;
+ ReducedSize += MFI->getObjectSize(Slot);
+ MFI->RemoveStackObject(Slot);
+ }
SortedSlots[I] = -1;
+ }
}
// This is a simple greedy algorithm for merging allocas. First, sort the
@@ -1339,7 +1355,7 @@ bool StackColoring::runOnMachineFunction(MachineFunction &Func) {
// Scan the entire function and update all machine operands that use frame
// indices to use the remapped frame index.
- if (!SlotRemap.empty()) {
+ if (RemovedSlots > 0) {
expungeSlotMap(SlotRemap, NumSlots);
remapInstructions(SlotRemap);
}
diff --git a/llvm/test/CodeGen/PowerPC/aix32-cc-abi-vaarg.ll b/llvm/test/CodeGen/PowerPC/aix32-cc-abi-vaarg.ll
index bf66a1ed042d22..1b0a803734ae9f 100644
--- a/llvm/test/CodeGen/PowerPC/aix32-cc-abi-vaarg.ll
+++ b/llvm/test/CodeGen/PowerPC/aix32-cc-abi-vaarg.ll
@@ -347,7 +347,6 @@ entry:
; 32BIT-LABEL: stack:
; 32BIT-DAG: - { id: 0, name: arg1, type: default, offset: 0, size: 4, alignment: 4,
-; 32BIT-DAG: - { id: 1, name: arg2, type: default, offset: 0, size: 4, alignment: 4,
; 32BIT-DAG: - { id: 2, name: '', type: default, offset: 0, size: 8, alignment: 8,
; 32BIT-DAG: - { id: 3, name: '', type: default, offset: 0, size: 8, alignment: 8,
diff --git a/llvm/test/CodeGen/PowerPC/aix64-cc-abi-vaarg.ll b/llvm/test/CodeGen/PowerPC/aix64-cc-abi-vaarg.ll
index ccf89aac2d5408..a8684fdfe1c568 100644
--- a/llvm/test/CodeGen/PowerPC/aix64-cc-abi-vaarg.ll
+++ b/llvm/test/CodeGen/PowerPC/aix64-cc-abi-vaarg.ll
@@ -138,9 +138,7 @@
; 64BIT-LABEL: fixedStack:
; 64BIT-DAG: - { id: 0, type: default, offset: 112, size: 8, alignment: 16, stack-id: default,
-; 64BIT-LABEL: stack:
-; 64BIT-DAG: - { id: 0, name: arg1, type: default, offset: 0, size: 8, alignment: 8,
-; 64BIT-DAG: - { id: 1, name: arg2, type: default, offset: 0, size: 8, alignment: 8,
+; 64BIT-LABEL: stack: []
; 64BIT-LABEL: body: |
; 64BIT-DAG: liveins: $x3, $x4, $x5, $x6, $x7, $x8, $x9, $x10
@@ -305,9 +303,7 @@
; 64BIT-LABEL: fixedStack:
; 64BIT-DAG: - { id: 0, type: default, offset: 152, size: 8
-; 64BIT-LABEL: stack:
-; 64BIT-DAG: - { id: 0, name: arg1, type: default, offset: 0, size: 8
-; 64BIT-DAG: - { id: 1, name: arg2, type: default, offset: 0, size: 8
+; 64BIT-LABEL: stack: []
; 64BIT-LABEL: body: |
; 64BIT-DAG: liveins: $f1, $f2, $f3, $f4, $f5, $f6, $f7, $f8, $f9, $f10, $f11, $f12, $f13
diff --git a/llvm/test/CodeGen/RISCV/dead-stack-slot.ll b/llvm/test/CodeGen/RISCV/dead-stack-slot.ll
new file mode 100644
index 00000000000000..49b0d2ab58c4f6
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/dead-stack-slot.ll
@@ -0,0 +1,25 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=riscv32 -verify-machineinstrs < %s \
+; RUN: | FileCheck %s
+; RUN: llc -mtriple=riscv64 -verify-machineinstrs < %s \
+; RUN: | FileCheck %s
+
+; Remove the lifetime-marked alloca, but not the unmarked one.
+define signext i32 @f1() nounwind {
+; CHECK-LABEL: f1:
+; CHECK: # %bb.0:
+; CHECK-NEXT: addi sp, sp, -32
+; CHECK-NEXT: li a0, 0
+; CHECK-NEXT: addi sp, sp, 32
+; CHECK-NEXT: ret
+ %1 = alloca [32 x i8], align 4
+ %2 = alloca [32 x i8], align 4
+ %3 = getelementptr inbounds [32 x i8], ptr %1, i64 0, i64 0
+ call void @llvm.lifetime.start.p0(i64 32, ptr nonnull %3)
+ call void @llvm.lifetime.end.p0(i64 32, ptr nonnull %3)
+ ret i32 0
+}
+
+declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture)
+declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture)
+
diff --git a/llvm/test/CodeGen/X86/StackColoring-tbaa.mir b/llvm/test/CodeGen/X86/StackColoring-tbaa.mir
index 6d7f294549d791..b4fdf4d2ec9176 100644
--- a/llvm/test/CodeGen/X86/StackColoring-tbaa.mir
+++ b/llvm/test/CodeGen/X86/StackColoring-tbaa.mir
@@ -53,7 +53,7 @@ body: |
; CHECK: [[LEA64r:%[0-9]+]]:gr64 = nuw LEA64r %stack.1.agg, 1, $noreg, 24, $noreg
; CHECK-NEXT: CMP8mi %stack.1.agg, 1, $noreg, 47, $noreg, 0, implicit-def $eflags :: (dereferenceable load (s8) from %ir.a22, !tbaa !2)
; CHECK-NEXT: [[CMOV64rm:%[0-9]+]]:gr64 = CMOV64rm [[LEA64r]], %stack.1.agg, 1, $noreg, 24, $noreg, 8, implicit $eflags :: (dereferenceable load (s64) from %ir.a2)
- ; CHECK-NEXT: [[MOV8rm:%[0-9]+]]:gr8 = MOV8rm killed [[CMOV64rm]], 1, $noreg, 16, $noreg :: (load (s8) from %ir.add.ptr.i, !tbaa !2)
+ ; CHECK-NEXT: [[MOV8rm:%[0-9]+]]:gr8 = MOV8rm killed [[CMOV64rm]], 1, $noreg, 16, $noreg :: (load (s8) from %ir.add.ptr.i)
; CHECK-NEXT: $al = COPY [[MOV8rm]]
; CHECK-NEXT: RET 0, $al
LIFETIME_START %stack.0.padding
diff --git a/llvm/test/DebugInfo/COFF/lexicalblock.ll b/llvm/test/DebugInfo/COFF/lexicalblock.ll
index 40dd8f894252c2..3bfae85f6c9bad 100644
--- a/llvm/test/DebugInfo/COFF/lexicalblock.ll
+++ b/llvm/test/DebugInfo/COFF/lexicalblock.ll
@@ -63,32 +63,12 @@
; CHECK: LocalSym {
; CHECK: VarName: localA
; CHECK: }
-; CHECK: LocalSym {
-; CHECK: VarName: localB
-; CHECK: }
-; CHECK: BlockSym {
-; CHECK: Kind: S_BLOCK32 {{.*}}
-; CHECK: BlockName:
-; CHECK: }
-; CHECK: ScopeEndSym {
-; CHECK: Kind: S_END {{.*}}
-; CHECK: }
-; CHECK: BlockSym {
-; CHECK: Kind: S_BLOCK32 {{.*}}
-; CHECK: BlockName:
-; CHECK: }
-; CHECK: ScopeEndSym {
-; CHECK: Kind: S_END {{.*}}
-; CHECK: }
; CHECK: BlockSym {
; CHECK: Kind: S_BLOCK32 {{.*}}
; CHECK: BlockName:
; CHECK: }
-; CHECK: ScopeEndSym {
-; CHECK: }
-; CHECK: BlockSym {
-; CHECK: Kind: S_BLOCK32 {{.*}}
-; CHECK: BlockName:
+; CHECK: LocalSym {
+; CHECK: VarName: localB
; CHECK: }
; CHECK: ScopeEndSym {
; CHECK: Kind: S_END {{.*}}
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