Reviewers: Jakob,
Description:
Merged r14169 into 3.17 branch.
Fix worst-case behavior of MergeRemovableSimulates().
BUG=v8:2612
[email protected]
Please review this at https://chromiumcodereview.appspot.com/14472003/
SVN Base: https://v8.googlecode.com/svn/branches/3.17
Affected files:
M src/hydrogen-instructions.h
M src/hydrogen-instructions.cc
M src/hydrogen.cc
M src/version.cc
M test/mjsunit/mjsunit.status
Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index
aef227f60d0b98a67c59c980fcbfc9947550a598..0f42e402f4a9fefd26503bdac51aed696e515778
100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -579,7 +579,7 @@ void HValue::Kill() {
HValue* operand = OperandAt(i);
if (operand == NULL) continue;
HUseListNode* first = operand->use_list_;
- if (first != NULL && first->value() == this && first->index() == i) {
+ if (first != NULL && first->value()->CheckFlag(kIsDead)) {
operand->use_list_ = first->tail();
}
}
@@ -1749,20 +1749,25 @@ void HPhi::AddIndirectUsesTo(int* dest) {
}
-void HSimulate::MergeInto(HSimulate* other) {
- for (int i = 0; i < values_.length(); ++i) {
- HValue* value = values_[i];
- if (HasAssignedIndexAt(i)) {
- other->AddAssignedValue(GetAssignedIndexAt(i), value);
- } else {
- if (other->pop_count_ > 0) {
- other->pop_count_--;
+void HSimulate::MergeWith(ZoneList<HSimulate*>* list) {
+ while (!list->is_empty()) {
+ HSimulate* from = list->RemoveLast();
+ ZoneList<HValue*>* from_values = &from->values_;
+ for (int i = 0; i < from_values->length(); ++i) {
+ if (from->HasAssignedIndexAt(i)) {
+ AddAssignedValue(from->GetAssignedIndexAt(i),
+ from_values->at(i));
} else {
- other->AddPushedValue(value);
+ if (pop_count_ > 0) {
+ pop_count_--;
+ } else {
+ AddPushedValue(from_values->at(i));
+ }
}
}
+ pop_count_ += from->pop_count_;
+ from->DeleteAndReplaceWith(NULL);
}
- other->pop_count_ += pop_count();
}
Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index
d2b3fc5d8c9de497316e5e8580acbffb3eca42ca..ea546212735a1c808d448b4c24e389bc42af8a97
100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -1696,7 +1696,7 @@ class HSimulate: public HInstruction {
return Representation::None();
}
- void MergeInto(HSimulate* other);
+ void MergeWith(ZoneList<HSimulate*>* list);
bool is_candidate_for_removal() { return removable_ ==
REMOVABLE_SIMULATE; }
DECLARE_CONCRETE_INSTRUCTION(Simulate)
Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index
4d9bc9bc64ef3b693e59c4d66645873af43a0cbf..ef5de6b1f94a1255a114d172b6ad3dfdd526d4be
100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -2971,10 +2971,11 @@ void HInferRepresentation::Analyze() {
void HGraph::MergeRemovableSimulates() {
+ ZoneList<HSimulate*> mergelist(2, zone());
for (int i = 0; i < blocks()->length(); ++i) {
HBasicBlock* block = blocks()->at(i);
- // Always reset the folding candidate at the start of a block.
- HSimulate* folding_candidate = NULL;
+ // Make sure the merge list is empty at the start of a block.
+ ASSERT(mergelist.is_empty());
// Nasty heuristic: Never remove the first simulate in a block. This
// just so happens to have a beneficial effect on register allocation.
bool first = true;
@@ -2985,33 +2986,38 @@ void HGraph::MergeRemovableSimulates() {
// in the outer environment.
// (Before each HEnterInlined, there is a non-foldable HSimulate
// anyway, so we get the barrier in the other direction for free.)
- if (folding_candidate != NULL) {
- folding_candidate->DeleteAndReplaceWith(NULL);
+ // Simply remove all accumulated simulates without merging. This
+ // is safe because simulates after instructions with side effects
+ // are never added to the merge list.
+ while (!mergelist.is_empty()) {
+ mergelist.RemoveLast()->DeleteAndReplaceWith(NULL);
}
- folding_candidate = NULL;
continue;
}
- // If we have an HSimulate and a candidate, perform the folding.
+ // Skip the non-simulates and the first simulate.
if (!current->IsSimulate()) continue;
if (first) {
first = false;
continue;
}
HSimulate* current_simulate = HSimulate::cast(current);
- if (folding_candidate != NULL) {
- folding_candidate->MergeInto(current_simulate);
- folding_candidate->DeleteAndReplaceWith(NULL);
- folding_candidate = NULL;
- }
- // Check if the current simulate is a candidate for folding.
- if (current_simulate->previous()->HasObservableSideEffects() &&
- !current_simulate->next()->IsSimulate()) {
- continue;
- }
- if (!current_simulate->is_candidate_for_removal()) {
+ if ((current_simulate->previous()->HasObservableSideEffects() &&
+ !current_simulate->next()->IsSimulate()) ||
+ !current_simulate->is_candidate_for_removal()) {
+ // This simulate is not suitable for folding.
+ // Fold the ones accumulated so far.
+ current_simulate->MergeWith(&mergelist);
continue;
+ } else {
+ // Accumulate this simulate for folding later on.
+ mergelist.Add(current_simulate, zone());
}
- folding_candidate = current_simulate;
+ }
+
+ if (!mergelist.is_empty()) {
+ // Merge the accumulated simulates at the end of the block.
+ HSimulate* last = mergelist.RemoveLast();
+ last->MergeWith(&mergelist);
}
}
}
Index: src/version.cc
diff --git a/src/version.cc b/src/version.cc
index
f7fb1ee3d7b25ef169fc605efe2146a86a1a66e0..f53a8a4106ac4c8aef940c5708a3330acb551385
100644
--- a/src/version.cc
+++ b/src/version.cc
@@ -35,7 +35,7 @@
#define MAJOR_VERSION 3
#define MINOR_VERSION 17
#define BUILD_NUMBER 6
-#define PATCH_LEVEL 9
+#define PATCH_LEVEL 10
// Use 1 for candidates and 0 otherwise.
// (Boolean macro values are not supported by all preprocessors.)
#define IS_CANDIDATE_VERSION 0
Index: test/mjsunit/mjsunit.status
diff --git a/test/mjsunit/mjsunit.status b/test/mjsunit/mjsunit.status
index
26c8359b6185fe18e91cc7ad597f2aa28bada52c..2dd43d986a91e4d593f16dfb1c5d0b694cccbbd9
100644
--- a/test/mjsunit/mjsunit.status
+++ b/test/mjsunit/mjsunit.status
@@ -49,6 +49,7 @@ compiler/regress-stacktrace-methods: PASS, SKIP if $mode
== debug
compiler/regress-funcaller: PASS, SKIP if $mode == debug
regress/regress-2318: PASS, SKIP if $mode == debug
regress/regress-create-exception: PASS, SKIP if $mode == debug
+regress/regress-2612: PASS, SKIP if $mode == debug
##############################################################################
# These use a built-in that's only present in debug mode. They take
--
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