Skip to content

Commit 5d21f75

Browse files
taewookohtaewookoh
committed
Revert b19ec1e
Summary: This reverts commit b19ec1e as it fails powerpc tests Subscribers: llvm-commits
1 parent 5c166f1 commit 5d21f75

File tree

7 files changed

+143
-205
lines changed

7 files changed

+143
-205
lines changed

‎llvm/include/llvm/Analysis/BranchProbabilityInfo.h

Lines changed: 2 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -34,7 +34,6 @@ namespace llvm {
3434
class Function;
3535
class LoopInfo;
3636
class raw_ostream;
37-
class PostDominatorTree;
3837
class TargetLibraryInfo;
3938
class Value;
4039

@@ -188,10 +187,8 @@ class BranchProbabilityInfo {
188187
/// Track the set of blocks that always lead to a cold call.
189188
SmallPtrSet<const BasicBlock *, 16> PostDominatedByColdCall;
190189

191-
void computePostDominatedByUnreachable(const Function &F,
192-
PostDominatorTree *PDT);
193-
void computePostDominatedByColdCall(const Function &F,
194-
PostDominatorTree *PDT);
190+
void updatePostDominatedByUnreachable(const BasicBlock *BB);
191+
void updatePostDominatedByColdCall(const BasicBlock *BB);
195192
bool calcUnreachableHeuristics(const BasicBlock *BB);
196193
bool calcMetadataWeights(const BasicBlock *BB);
197194
bool calcColdCallHeuristics(const BasicBlock *BB);

‎llvm/lib/Analysis/BranchProbabilityInfo.cpp

Lines changed: 57 additions & 75 deletions
Original file line numberDiff line numberDiff line change
@@ -16,7 +16,6 @@
1616
#include "llvm/ADT/STLExtras.h"
1717
#include "llvm/ADT/SmallVector.h"
1818
#include "llvm/Analysis/LoopInfo.h"
19-
#include "llvm/Analysis/PostDominators.h"
2019
#include "llvm/Analysis/TargetLibraryInfo.h"
2120
#include "llvm/IR/Attributes.h"
2221
#include "llvm/IR/BasicBlock.h"
@@ -147,83 +146,69 @@ static const uint32_t IH_TAKEN_WEIGHT = 1024 * 1024 - 1;
147146
/// instruction. This is essentially never taken.
148147
static const uint32_t IH_NONTAKEN_WEIGHT = 1;
149148

150-
static void UpdatePDTWorklist(const BasicBlock *BB, PostDominatorTree *PDT,
151-
SmallVectorImpl<const BasicBlock *> &WorkList,
152-
SmallPtrSetImpl<const BasicBlock *> &TargetSet) {
153-
SmallVector<BasicBlock *, 8> Descendants;
154-
SmallPtrSet<const BasicBlock *, 16> NewItems;
155-
156-
PDT->getDescendants(const_cast<BasicBlock *>(BB), Descendants);
157-
for (auto *BB : Descendants)
158-
if (TargetSet.insert(BB).second)
159-
for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
160-
if (!TargetSet.count(*PI))
161-
NewItems.insert(*PI);
162-
WorkList.insert(WorkList.end(), NewItems.begin(), NewItems.end());
163-
}
164-
165-
/// Compute a set of basic blocks that are post-dominated by unreachables.
166-
void BranchProbabilityInfo::computePostDominatedByUnreachable(
167-
const Function &F, PostDominatorTree *PDT) {
168-
SmallVector<const BasicBlock *, 8> WorkList;
169-
for (auto &BB : F) {
170-
const Instruction *TI = BB.getTerminator();
171-
if (TI->getNumSuccessors() == 0) {
172-
if (isa<UnreachableInst>(TI) ||
173-
// If this block is terminated by a call to
174-
// @llvm.experimental.deoptimize then treat it like an unreachable
175-
// since the @llvm.experimental.deoptimize call is expected to
176-
// practically never execute.
177-
BB.getTerminatingDeoptimizeCall())
178-
UpdatePDTWorklist(&BB, PDT, WorkList, PostDominatedByUnreachable);
179-
}
149+
/// Add \p BB to PostDominatedByUnreachable set if applicable.
150+
void
151+
BranchProbabilityInfo::updatePostDominatedByUnreachable(const BasicBlock *BB) {
152+
const Instruction *TI = BB->getTerminator();
153+
if (TI->getNumSuccessors() == 0) {
154+
if (isa<UnreachableInst>(TI) ||
155+
// If this block is terminated by a call to
156+
// @llvm.experimental.deoptimize then treat it like an unreachable since
157+
// the @llvm.experimental.deoptimize call is expected to practically
158+
// never execute.
159+
BB->getTerminatingDeoptimizeCall())
160+
PostDominatedByUnreachable.insert(BB);
161+
return;
180162
}
181163

182-
while (!WorkList.empty()) {
183-
const BasicBlock *BB = WorkList.pop_back_val();
184-
if (PostDominatedByUnreachable.count(BB))
185-
continue;
186-
// If the terminator is an InvokeInst, check only the normal destination
187-
// block as the unwind edge of InvokeInst is also very unlikely taken.
188-
if (auto *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
189-
if (PostDominatedByUnreachable.count(II->getNormalDest()))
190-
UpdatePDTWorklist(BB, PDT, WorkList, PostDominatedByUnreachable);
191-
}
192-
// If all the successors are unreachable, BB is unreachable as well.
193-
else if (!successors(BB).empty() &&
194-
llvm::all_of(successors(BB), [this](const BasicBlock *Succ) {
195-
return PostDominatedByUnreachable.count(Succ);
196-
}))
197-
UpdatePDTWorklist(BB, PDT, WorkList, PostDominatedByUnreachable);
164+
// If the terminator is an InvokeInst, check only the normal destination block
165+
// as the unwind edge of InvokeInst is also very unlikely taken.
166+
if (auto *II = dyn_cast<InvokeInst>(TI)) {
167+
if (PostDominatedByUnreachable.count(II->getNormalDest()))
168+
PostDominatedByUnreachable.insert(BB);
169+
return;
198170
}
171+
172+
for (auto *I : successors(BB))
173+
// If any of successor is not post dominated then BB is also not.
174+
if (!PostDominatedByUnreachable.count(I))
175+
return;
176+
177+
PostDominatedByUnreachable.insert(BB);
199178
}
200179

201-
/// compute a set of basic blocks that are post-dominated by ColdCalls.
202-
void BranchProbabilityInfo::computePostDominatedByColdCall(
203-
const Function &F, PostDominatorTree *PDT) {
204-
SmallVector<const BasicBlock *, 8> WorkList;
205-
for (auto &BB : F)
206-
for (auto &I : BB)
207-
if (const CallInst *CI = dyn_cast<CallInst>(&I))
208-
if (CI->hasFnAttr(Attribute::Cold))
209-
UpdatePDTWorklist(&BB, PDT, WorkList, PostDominatedByColdCall);
180+
/// Add \p BB to PostDominatedByColdCall set if applicable.
181+
void
182+
BranchProbabilityInfo::updatePostDominatedByColdCall(const BasicBlock *BB) {
183+
assert(!PostDominatedByColdCall.count(BB));
184+
const Instruction *TI = BB->getTerminator();
185+
if (TI->getNumSuccessors() == 0)
186+
return;
210187

211-
while (!WorkList.empty()) {
212-
const BasicBlock *BB = WorkList.pop_back_val();
188+
// If all of successor are post dominated then BB is also done.
189+
if (llvm::all_of(successors(BB), [&](const BasicBlock *SuccBB) {
190+
return PostDominatedByColdCall.count(SuccBB);
191+
})) {
192+
PostDominatedByColdCall.insert(BB);
193+
return;
194+
}
213195

214-
// If the terminator is an InvokeInst, check only the normal destination
215-
// block as the unwind edge of InvokeInst is also very unlikely taken.
216-
if (auto *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
217-
if (PostDominatedByColdCall.count(II->getNormalDest()))
218-
UpdatePDTWorklist(BB, PDT, WorkList, PostDominatedByColdCall);
196+
// If the terminator is an InvokeInst, check only the normal destination
197+
// block as the unwind edge of InvokeInst is also very unlikely taken.
198+
if (auto *II = dyn_cast<InvokeInst>(TI))
199+
if (PostDominatedByColdCall.count(II->getNormalDest())) {
200+
PostDominatedByColdCall.insert(BB);
201+
return;
219202
}
220-
// If all of successor are post dominated then BB is also done.
221-
else if (!successors(BB).empty() &&
222-
llvm::all_of(successors(BB), [this](const BasicBlock *Succ) {
223-
return PostDominatedByColdCall.count(Succ);
224-
}))
225-
UpdatePDTWorklist(BB, PDT, WorkList, PostDominatedByColdCall);
226-
}
203+
204+
// Otherwise, if the block itself contains a cold function, add it to the
205+
// set of blocks post-dominated by a cold call.
206+
for (auto &I : *BB)
207+
if (const CallInst *CI = dyn_cast<CallInst>(&I))
208+
if (CI->hasFnAttr(Attribute::Cold)) {
209+
PostDominatedByColdCall.insert(BB);
210+
return;
211+
}
227212
}
228213

229214
/// Calculate edge weights for successors lead to unreachable.
@@ -998,16 +983,13 @@ void BranchProbabilityInfo::calculate(const Function &F, const LoopInfo &LI,
998983
LLVM_DEBUG(dbgs() << "\n");
999984
}
1000985

1001-
std::unique_ptr<PostDominatorTree> PDT =
1002-
std::make_unique<PostDominatorTree>(const_cast<Function &>(F));
1003-
computePostDominatedByUnreachable(F, PDT.get());
1004-
computePostDominatedByColdCall(F, PDT.get());
1005-
1006986
// Walk the basic blocks in post-order so that we can build up state about
1007987
// the successors of a block iteratively.
1008988
for (auto BB : post_order(&F.getEntryBlock())) {
1009989
LLVM_DEBUG(dbgs() << "Computing probabilities for " << BB->getName()
1010990
<< "\n");
991+
updatePostDominatedByUnreachable(BB);
992+
updatePostDominatedByColdCall(BB);
1011993
// If there is no at least two successors, no sense to set probability.
1012994
if (BB->getTerminator()->getNumSuccessors() < 2)
1013995
continue;

‎llvm/test/Analysis/BranchProbabilityInfo/basic.ll

Lines changed: 0 additions & 18 deletions
Original file line numberDiff line numberDiff line change
@@ -141,24 +141,6 @@ exit:
141141
ret i32 %result
142142
}
143143

144-
define i32 @test_cold_loop(i32 %a, i32 %b) {
145-
entry:
146-
%cond1 = icmp eq i32 %a, 42
147-
br i1 %cond1, label %header, label %exit
148-
149-
header:
150-
br label %body
151-
152-
body:
153-
%cond2 = icmp eq i32 %b, 42
154-
br i1 %cond2, label %header, label %exit
155-
; CHECK: edge body -> header probability is 0x40000000 / 0x80000000 = 50.00%
156-
157-
exit:
158-
call void @coldfunc()
159-
ret i32 %b
160-
}
161-
162144
declare i32 @regular_function(i32 %i)
163145

164146
define i32 @test_cold_call_sites_with_prof(i32 %a, i32 %b, i1 %flag, i1 %flag2) {

‎llvm/test/Analysis/BranchProbabilityInfo/noreturn.ll

Lines changed: 0 additions & 26 deletions
Original file line numberDiff line numberDiff line change
@@ -79,32 +79,6 @@ exit:
7979
ret i32 %b
8080
}
8181

82-
define i32 @test4(i32 %a, i32 %b) {
83-
; CHECK: Printing analysis {{.*}} for function 'test4'
84-
; Make sure we handle loops post-dominated by unreachables.
85-
entry:
86-
%cond1 = icmp eq i32 %a, 42
87-
br i1 %cond1, label %header, label %exit
88-
; CHECK: edge entry -> header probability is 0x00000001 / 0x80000000 = 0.00%
89-
; CHECK: edge entry -> exit probability is 0x7fffffff / 0x80000000 = 100.00% [HOT edge]
90-
91-
header:
92-
br label %body
93-
94-
body:
95-
%cond2 = icmp eq i32 %a, 42
96-
br i1 %cond2, label %header, label %abort
97-
; CHECK: edge body -> header probability is 0x40000000 / 0x80000000 = 50.00%
98-
; CHECK: edge body -> abort probability is 0x40000000 / 0x80000000 = 50.00%
99-
100-
abort:
101-
call void @abort() noreturn
102-
unreachable
103-
104-
exit:
105-
ret i32 %b
106-
}
107-
10882
@_ZTIi = external global i8*
10983

11084
; CHECK-LABEL: throwSmallException

‎llvm/test/CodeGen/X86/block-placement.ll

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -358,11 +358,11 @@ define void @unnatural_cfg2(i32* %p0, i32 %a0) {
358358
; CHECK: %loop.header
359359
; CHECK: %loop.body1
360360
; CHECK: %loop.body2
361-
; CHECK: %loop.body3
362-
; CHECK: %loop.inner1.begin
363361
; CHECK: %loop.body4
364362
; CHECK: %loop.inner2.begin
365363
; CHECK: %loop.inner2.begin
364+
; CHECK: %loop.body3
365+
; CHECK: %loop.inner1.begin
366366
; CHECK: %bail
367367

368368
entry:

‎llvm/test/CodeGen/X86/pr37916.ll

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -7,6 +7,7 @@
77
define void @fn1() local_unnamed_addr {
88
; CHECK-LABEL: fn1:
99
; CHECK: # %bb.0: # %entry
10+
; CHECK-NEXT: .p2align 4, 0x90
1011
; CHECK-NEXT: .LBB0_1: # %if.end
1112
; CHECK-NEXT: # =>This Inner Loop Header: Depth=1
1213
; CHECK-NEXT: movl a+4, %eax

0 commit comments

Comments
 (0)