[llvm] r265726 - Do not select EhPad BB in MachineBlockPlacement when there is regular BB to schedule
Amaury Sechet via llvm-commits
llvm-commits at lists.llvm.org
Thu Apr 7 14:29:40 PDT 2016
Author: deadalnix
Date: Thu Apr 7 16:29:39 2016
New Revision: 265726
URL: http://llvm.org/viewvc/llvm-project?rev=265726&view=rev
Log:
Do not select EhPad BB in MachineBlockPlacement when there is regular BB to schedule
Summary:
EHPad BB are not entered the classic way and therefor do not need to be placed after their predecessors. This patch make sure EHPad BB are not chosen amongst successors to form chains, and are selected as last resort when selecting the best candidate.
EHPad are scheduled in reverse probability order in order to have them flow into each others naturally.
Reviewers: chandlerc, majnemer, rafael, MatzeB, escha, silvas
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D17625
Removed:
llvm/trunk/test/CodeGen/PowerPC/pr25802.ll
Modified:
llvm/trunk/lib/CodeGen/MachineBlockPlacement.cpp
llvm/trunk/test/CodeGen/X86/block-placement.ll
llvm/trunk/test/CodeGen/X86/seh-safe-div-win32.ll
llvm/trunk/test/CodeGen/X86/seh-safe-div.ll
llvm/trunk/test/CodeGen/X86/win-catchpad.ll
Modified: llvm/trunk/lib/CodeGen/MachineBlockPlacement.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineBlockPlacement.cpp?rev=265726&r1=265725&r2=265726&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineBlockPlacement.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineBlockPlacement.cpp Thu Apr 7 16:29:39 2016
@@ -262,6 +262,7 @@ class MachineBlockPlacement : public Mac
void markChainSuccessors(BlockChain &Chain, MachineBasicBlock *LoopHeaderBB,
SmallVectorImpl<MachineBasicBlock *> &BlockWorkList,
+ SmallVectorImpl<MachineBasicBlock *> &EHPadWorkList,
const BlockFilterSet *BlockFilter = nullptr);
MachineBasicBlock *selectBestSuccessor(MachineBasicBlock *BB,
BlockChain &Chain,
@@ -282,9 +283,11 @@ class MachineBlockPlacement : public Mac
void fillWorkLists(MachineBasicBlock *MBB,
SmallPtrSetImpl<BlockChain *> &UpdatedPreds,
SmallVectorImpl<MachineBasicBlock *> &BlockWorkList,
+ SmallVectorImpl<MachineBasicBlock *> &EHPadWorkList,
const BlockFilterSet *BlockFilter);
void buildChain(MachineBasicBlock *BB, BlockChain &Chain,
SmallVectorImpl<MachineBasicBlock *> &BlockWorkList,
+ SmallVectorImpl<MachineBasicBlock *> &EHPadWorkList,
const BlockFilterSet *BlockFilter = nullptr);
MachineBasicBlock *findBestLoopTop(MachineLoop &L,
const BlockFilterSet &LoopBlockSet);
@@ -350,6 +353,7 @@ static std::string getBlockName(MachineB
void MachineBlockPlacement::markChainSuccessors(
BlockChain &Chain, MachineBasicBlock *LoopHeaderBB,
SmallVectorImpl<MachineBasicBlock *> &BlockWorkList,
+ SmallVectorImpl<MachineBasicBlock *> &EHPadWorkList,
const BlockFilterSet *BlockFilter) {
// Walk all the blocks in this chain, marking their successors as having
// a predecessor placed.
@@ -368,8 +372,15 @@ void MachineBlockPlacement::markChainSuc
// This is a cross-chain edge that is within the loop, so decrement the
// loop predecessor count of the destination chain.
- if (SuccChain.UnscheduledPredecessors > 0 && --SuccChain.UnscheduledPredecessors == 0)
- BlockWorkList.push_back(*SuccChain.begin());
+ if (SuccChain.UnscheduledPredecessors == 0 ||
+ --SuccChain.UnscheduledPredecessors > 0)
+ continue;
+
+ auto *MBB = *SuccChain.begin();
+ if (MBB->isEHPad())
+ EHPadWorkList.push_back(MBB);
+ else
+ BlockWorkList.push_back(MBB);
}
}
}
@@ -412,7 +423,7 @@ MachineBlockPlacement::selectBestSuccess
SmallVector<MachineBasicBlock *, 4> Successors;
for (MachineBasicBlock *Succ : BB->successors()) {
bool SkipSucc = false;
- if (BlockFilter && !BlockFilter->count(Succ)) {
+ if (Succ->isEHPad() || (BlockFilter && !BlockFilter->count(Succ))) {
SkipSucc = true;
} else {
BlockChain *SuccChain = BlockToChain[Succ];
@@ -532,9 +543,16 @@ MachineBasicBlock *MachineBlockPlacement
}),
WorkList.end());
+ if (WorkList.empty())
+ return nullptr;
+
+ bool IsEHPad = WorkList[0]->isEHPad();
+
MachineBasicBlock *BestBlock = nullptr;
BlockFrequency BestFreq;
for (MachineBasicBlock *MBB : WorkList) {
+ assert(MBB->isEHPad() == IsEHPad);
+
BlockChain &SuccChain = *BlockToChain[MBB];
if (&SuccChain == &Chain)
continue;
@@ -544,11 +562,32 @@ MachineBasicBlock *MachineBlockPlacement
BlockFrequency CandidateFreq = MBFI->getBlockFreq(MBB);
DEBUG(dbgs() << " " << getBlockName(MBB) << " -> ";
MBFI->printBlockFreq(dbgs(), CandidateFreq) << " (freq)\n");
- if (BestBlock && BestFreq >= CandidateFreq)
+
+ // For ehpad, we layout the least probable first as to avoid jumping back
+ // from least probable landingpads to more probable ones.
+ //
+ // FIXME: Using probability is probably (!) not the best way to achieve
+ // this. We should probably have a more principled approach to layout
+ // cleanup code.
+ //
+ // The goal is to get:
+ //
+ // +--------------------------+
+ // | V
+ // InnerLp -> InnerCleanup OuterLp -> OuterCleanup -> Resume
+ //
+ // Rather than:
+ //
+ // +-------------------------------------+
+ // V |
+ // OuterLp -> OuterCleanup -> Resume InnerLp -> InnerCleanup
+ if (BestBlock && (IsEHPad ^ (BestFreq >= CandidateFreq)))
continue;
+
BestBlock = MBB;
BestFreq = CandidateFreq;
}
+
return BestBlock;
}
@@ -582,6 +621,7 @@ void MachineBlockPlacement::fillWorkList
MachineBasicBlock *MBB,
SmallPtrSetImpl<BlockChain *> &UpdatedPreds,
SmallVectorImpl<MachineBasicBlock *> &BlockWorkList,
+ SmallVectorImpl<MachineBasicBlock *> &EHPadWorkList,
const BlockFilterSet *BlockFilter = nullptr) {
BlockChain &Chain = *BlockToChain[MBB];
if (!UpdatedPreds.insert(&Chain).second)
@@ -599,13 +639,20 @@ void MachineBlockPlacement::fillWorkList
}
}
- if (Chain.UnscheduledPredecessors == 0)
- BlockWorkList.push_back(*Chain.begin());
+ if (Chain.UnscheduledPredecessors != 0)
+ return;
+
+ MBB = *Chain.begin();
+ if (MBB->isEHPad())
+ EHPadWorkList.push_back(MBB);
+ else
+ BlockWorkList.push_back(MBB);
}
void MachineBlockPlacement::buildChain(
MachineBasicBlock *BB, BlockChain &Chain,
SmallVectorImpl<MachineBasicBlock *> &BlockWorkList,
+ SmallVectorImpl<MachineBasicBlock *> &EHPadWorkList,
const BlockFilterSet *BlockFilter) {
assert(BB);
assert(BlockToChain[BB] == &Chain);
@@ -613,7 +660,8 @@ void MachineBlockPlacement::buildChain(
MachineFunction::iterator PrevUnplacedBlockIt = F.begin();
MachineBasicBlock *LoopHeaderBB = BB;
- markChainSuccessors(Chain, LoopHeaderBB, BlockWorkList, BlockFilter);
+ markChainSuccessors(Chain, LoopHeaderBB, BlockWorkList, EHPadWorkList,
+ BlockFilter);
BB = *std::prev(Chain.end());
for (;;) {
assert(BB);
@@ -629,6 +677,8 @@ void MachineBlockPlacement::buildChain(
// this point. This won't be a fallthrough, but it will increase locality.
if (!BestSucc)
BestSucc = selectBestCandidateBlock(Chain, BlockWorkList);
+ if (!BestSucc)
+ BestSucc = selectBestCandidateBlock(Chain, EHPadWorkList);
if (!BestSucc) {
BestSucc =
@@ -647,7 +697,8 @@ void MachineBlockPlacement::buildChain(
SuccChain.UnscheduledPredecessors = 0;
DEBUG(dbgs() << "Merging from " << getBlockName(BB) << " to "
<< getBlockName(BestSucc) << "\n");
- markChainSuccessors(SuccChain, LoopHeaderBB, BlockWorkList, BlockFilter);
+ markChainSuccessors(SuccChain, LoopHeaderBB, BlockWorkList, EHPadWorkList,
+ BlockFilter);
Chain.merge(BestSucc, &SuccChain);
BB = *std::prev(Chain.end());
}
@@ -1067,6 +1118,7 @@ void MachineBlockPlacement::buildLoopCha
buildLoopChains(F, *InnerLoop);
SmallVector<MachineBasicBlock *, 16> BlockWorkList;
+ SmallVector<MachineBasicBlock *, 16> EHPadWorkList;
BlockFilterSet LoopBlockSet = collectLoopBlockSet(F, L);
// Check if we have profile data for this function. If yes, we will rotate
@@ -1100,9 +1152,10 @@ void MachineBlockPlacement::buildLoopCha
UpdatedPreds.insert(&LoopChain);
for (MachineBasicBlock *LoopBB : LoopBlockSet)
- fillWorkLists(LoopBB, UpdatedPreds, BlockWorkList, &LoopBlockSet);
+ fillWorkLists(LoopBB, UpdatedPreds, BlockWorkList, EHPadWorkList,
+ &LoopBlockSet);
- buildChain(LoopTop, LoopChain, BlockWorkList, &LoopBlockSet);
+ buildChain(LoopTop, LoopChain, BlockWorkList, EHPadWorkList, &LoopBlockSet);
if (RotateLoopWithProfile)
rotateLoopWithProfile(LoopChain, L, LoopBlockSet);
@@ -1199,13 +1252,14 @@ void MachineBlockPlacement::buildCFGChai
buildLoopChains(F, *L);
SmallVector<MachineBasicBlock *, 16> BlockWorkList;
+ SmallVector<MachineBasicBlock *, 16> EHPadWorkList;
SmallPtrSet<BlockChain *, 4> UpdatedPreds;
for (MachineBasicBlock &MBB : F)
- fillWorkLists(&MBB, UpdatedPreds, BlockWorkList);
+ fillWorkLists(&MBB, UpdatedPreds, BlockWorkList, EHPadWorkList);
BlockChain &FunctionChain = *BlockToChain[&F.front()];
- buildChain(&F.front(), FunctionChain, BlockWorkList);
+ buildChain(&F.front(), FunctionChain, BlockWorkList, EHPadWorkList);
#ifndef NDEBUG
typedef SmallPtrSet<MachineBasicBlock *, 16> FunctionBlockSetType;
Removed: llvm/trunk/test/CodeGen/PowerPC/pr25802.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/PowerPC/pr25802.ll?rev=265725&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/PowerPC/pr25802.ll (original)
+++ llvm/trunk/test/CodeGen/PowerPC/pr25802.ll (removed)
@@ -1,52 +0,0 @@
-; RUN: llc < %s | FileCheck %s
-; CHECK: .long .Ltmp9-.Ltmp8 # Call between .Ltmp8 and .Ltmp9
-
-; We used to crash in filetype=obj when computing a negative value.
-; RUN: llc -filetype=obj < %s
-
-target triple = "powerpc--netbsd"
- at _ZTI1I = external constant { i8*, i8* }
-define void @f(i8 %foo, i32 %bar) personality i8* bitcast (void ()* @g to i8*) {
- invoke void @g()
- to label %try.cont unwind label %lpad
-lpad: ; preds = %0
- %tmp = landingpad { i8*, i32 }
- catch i8* bitcast ({ i8*, i8* }* @_ZTI1I to i8*)
- br i1 undef, label %catch10, label %catch
-catch10: ; preds = %lpad
- %tmp8 = load i32, i32* undef, align 4
- %conv.i.i = zext i8 %foo to i32
- %cond.i.i = select i1 undef, i32 %conv.i.i, i32 %tmp8
- invoke void @_Z24__put_character_sequenceIccEvR1AIT_T0_Ej(i32 %cond.i.i)
- to label %invoke.cont20 unwind label %lpad15
-invoke.cont20: ; preds = %catch10
- ret void
-try.cont: ; preds = %0
- ret void
-catch: ; preds = %lpad
- %tmp14 = load i32, i32* undef, align 4
- %conv.i.i34 = zext i8 %foo to i32
- %cond.i.i35 = select i1 undef, i32 %conv.i.i34, i32 %tmp14
- invoke void @_Z24__put_character_sequenceIccEvR1AIT_T0_Ej(i32 %cond.i.i35)
- to label %invoke.cont8 unwind label %lpad3
-invoke.cont8: ; preds = %call2.i.i.noexc36
- ret void
-lpad3: ; preds = %call2.i.i.noexc36, %catch
- %tmp16 = landingpad { i8*, i32 }
- cleanup
- invoke void @g()
- to label %eh.resume unwind label %terminate.lpad
-lpad15: ; preds = %catch10
- %tmp19 = landingpad { i8*, i32 }
- cleanup
- invoke void @g()
- to label %eh.resume unwind label %terminate.lpad
-eh.resume: ; preds = %lpad15, %lpad3
- ret void
-terminate.lpad: ; preds = %lpad15, %lpad3
- %tmp22 = landingpad { i8*, i32 }
- catch i8* null
- ret void
-}
-declare void @g()
-declare void @_Z24__put_character_sequenceIccEvR1AIT_T0_Ej(i32)
Modified: llvm/trunk/test/CodeGen/X86/block-placement.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/block-placement.ll?rev=265726&r1=265725&r2=265726&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/block-placement.ll (original)
+++ llvm/trunk/test/CodeGen/X86/block-placement.ll Thu Apr 7 16:29:39 2016
@@ -1083,3 +1083,96 @@ exit:
%ret = phi i32 [ %val1, %then ], [ %val2, %else ]
ret i32 %ret
}
+
+; Make sure we put landingpads out of the way.
+declare i32 @pers(...)
+
+declare i32 @foo();
+
+declare i32 @bar();
+
+define i32 @test_lp(i32 %a) personality i32 (...)* @pers {
+; CHECK-LABEL: test_lp:
+; CHECK: %entry
+; CHECK: %hot
+; CHECK: %then
+; CHECK: %cold
+; CHECK: %coldlp
+; CHECK: %hotlp
+; CHECK: %lpret
+entry:
+ %0 = icmp sgt i32 %a, 1
+ br i1 %0, label %hot, label %cold, !prof !4
+
+hot:
+ %1 = invoke i32 @foo()
+ to label %then unwind label %hotlp
+
+cold:
+ %2 = invoke i32 @bar()
+ to label %then unwind label %coldlp
+
+then:
+ %3 = phi i32 [ %1, %hot ], [ %2, %cold ]
+ ret i32 %3
+
+hotlp:
+ %4 = landingpad { i8*, i32 }
+ cleanup
+ br label %lpret
+
+coldlp:
+ %5 = landingpad { i8*, i32 }
+ cleanup
+ br label %lpret
+
+lpret:
+ %6 = phi i32 [-1, %hotlp], [-2, %coldlp]
+ %7 = add i32 %6, 42
+ ret i32 %7
+}
+
+!4 = !{!"branch_weights", i32 65536, i32 0}
+
+; Make sure that ehpad are scheduled from the least probable one
+; to the most probable one. See selectBestCandidateBlock as to why.
+declare void @clean();
+
+define void @test_flow_unwind() personality i32 (...)* @pers {
+; CHECK-LABEL: test_flow_unwind:
+; CHECK: %entry
+; CHECK: %then
+; CHECK: %exit
+; CHECK: %innerlp
+; CHECK: %outerlp
+; CHECK: %outercleanup
+entry:
+ %0 = invoke i32 @foo()
+ to label %then unwind label %outerlp
+
+then:
+ %1 = invoke i32 @bar()
+ to label %exit unwind label %innerlp
+
+exit:
+ ret void
+
+innerlp:
+ %2 = landingpad { i8*, i32 }
+ cleanup
+ br label %innercleanup
+
+outerlp:
+ %3 = landingpad { i8*, i32 }
+ cleanup
+ br label %outercleanup
+
+outercleanup:
+ %4 = phi { i8*, i32 } [%2, %innercleanup], [%3, %outerlp]
+ call void @clean()
+ resume { i8*, i32 } %4
+
+innercleanup:
+ call void @clean()
+ br label %outercleanup
+}
Modified: llvm/trunk/test/CodeGen/X86/seh-safe-div-win32.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/seh-safe-div-win32.ll?rev=265726&r1=265725&r2=265726&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/seh-safe-div-win32.ll (original)
+++ llvm/trunk/test/CodeGen/X86/seh-safe-div-win32.ll Thu Apr 7 16:29:39 2016
@@ -65,13 +65,13 @@ __try.cont:
; Landing pad code
-; CHECK: [[handler0:LBB0_[0-9]+]]: # %handler0
+; CHECK: [[handler1:LBB0_[0-9]+]]: # %handler1
; Restore SP
; CHECK: movl {{.*}}(%ebp), %esp
; CHECK: calll _puts
; CHECK: jmp [[cont_bb]]
-; CHECK: [[handler1:LBB0_[0-9]+]]: # %handler1
+; CHECK: [[handler0:LBB0_[0-9]+]]: # %handler0
; Restore SP
; CHECK: movl {{.*}}(%ebp), %esp
; CHECK: calll _puts
Modified: llvm/trunk/test/CodeGen/X86/seh-safe-div.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/seh-safe-div.ll?rev=265726&r1=265725&r2=265726&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/seh-safe-div.ll (original)
+++ llvm/trunk/test/CodeGen/X86/seh-safe-div.ll Thu Apr 7 16:29:39 2016
@@ -67,14 +67,14 @@ __try.cont:
; Landing pad code
-; CHECK: [[handler0:\.LBB0_[0-9]+]]: # %handler0
+; CHECK: [[handler1:\.LBB0_[0-9]+]]: # %handler1
; CHECK: callq puts
-; CHECK: movl $-1, [[rloc]]
+; CHECK: movl $-2, [[rloc]]
; CHECK: jmp [[cont_bb]]
-; CHECK: [[handler1:\.LBB0_[0-9]+]]: # %handler1
+; CHECK: [[handler0:\.LBB0_[0-9]+]]: # %handler0
; CHECK: callq puts
-; CHECK: movl $-2, [[rloc]]
+; CHECK: movl $-1, [[rloc]]
; CHECK: jmp [[cont_bb]]
; CHECK: .seh_handlerdata
Modified: llvm/trunk/test/CodeGen/X86/win-catchpad.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/win-catchpad.ll?rev=265726&r1=265725&r2=265726&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/win-catchpad.ll (original)
+++ llvm/trunk/test/CodeGen/X86/win-catchpad.ll Thu Apr 7 16:29:39 2016
@@ -63,17 +63,17 @@ try.cont:
; X86: [[contbb:LBB0_[0-9]+]]: # %try.cont
; X86: retl
-; X86: [[restorebb1:LBB0_[0-9]+]]: # Block address taken
-; X86-NEXT: # %handler1
-; X86-NEXT: addl $12, %ebp
-; X86: jmp [[contbb]]
-
; FIXME: These should be de-duplicated.
; X86: [[restorebb2:LBB0_[0-9]+]]: # Block address taken
; X86-NEXT: # %handler2
; X86-NEXT: addl $12, %ebp
; X86: jmp [[contbb]]
+; X86: [[restorebb1:LBB0_[0-9]+]]: # Block address taken
+; X86-NEXT: # %handler1
+; X86-NEXT: addl $12, %ebp
+; X86: jmp [[contbb]]
+
; X86: "?catch$[[catch1bb:[0-9]+]]@?0?try_catch_catch at 4HA":
; X86: LBB0_[[catch1bb]]: # %handler1{{$}}
; X86: pushl %ebp
More information about the llvm-commits
mailing list