Reuse HUseListNode<>s when replacing instruction or input.
Compiling the Nexus 5 boot image with the 64-bit dex2oat
on host this CL reduces the memory used for compiling the
most hungry method, BatteryStats.dumpLocked(), by ~5.6MiB:
Before:
MEM: used: 44393040, allocated: 45361248, lost: 968208
Number of arenas allocated: 319,
Number of allocations: 815492, avg size: 54
...
UseListNode 10308480
...
After:
MEM: used: 38554536, allocated: 39463008, lost: 908472
Number of arenas allocated: 274,
Number of allocations: 572221, avg size: 67
...
UseListNode 4469976
...
With 32-bit dex2oat, the UseListNode would be 2/3 of the
values for 64-bit dex2oat (both before and after).
Bug: 28173563
Change-Id: Ia4fabe03568f0e0dbf2cdf2b031863602aea3530
diff --git a/compiler/optimizing/nodes.cc b/compiler/optimizing/nodes.cc
index d259c21..7c6e931 100644
--- a/compiler/optimizing/nodes.cc
+++ b/compiler/optimizing/nodes.cc
@@ -1005,28 +1005,33 @@
void HInstruction::ReplaceWith(HInstruction* other) {
DCHECK(other != nullptr);
- for (const HUseListNode<HInstruction*>& use : GetUses()) {
- HInstruction* user = use.GetUser();
- size_t input_index = use.GetIndex();
- user->SetRawInputAt(input_index, other);
- other->AddUseAt(user, input_index);
- }
+ // Note: fixup_end remains valid across splice_after().
+ auto fixup_end = other->uses_.empty() ? other->uses_.begin() : ++other->uses_.begin();
+ other->uses_.splice_after(other->uses_.before_begin(), uses_);
+ other->FixUpUserRecordsAfterUseInsertion(fixup_end);
- for (const HUseListNode<HEnvironment*>& use : GetEnvUses()) {
- HEnvironment* user = use.GetUser();
- size_t input_index = use.GetIndex();
- user->SetRawEnvAt(input_index, other);
- other->AddEnvUseAt(user, input_index);
- }
+ // Note: env_fixup_end remains valid across splice_after().
+ auto env_fixup_end =
+ other->env_uses_.empty() ? other->env_uses_.begin() : ++other->env_uses_.begin();
+ other->env_uses_.splice_after(other->env_uses_.before_begin(), env_uses_);
+ other->FixUpUserRecordsAfterEnvUseInsertion(env_fixup_end);
- uses_.clear();
- env_uses_.clear();
+ DCHECK(uses_.empty());
+ DCHECK(env_uses_.empty());
}
void HInstruction::ReplaceInput(HInstruction* replacement, size_t index) {
- RemoveAsUserOfInput(index);
- SetRawInputAt(index, replacement);
- replacement->AddUseAt(this, index);
+ HUserRecord<HInstruction*> input_use = InputRecordAt(index);
+ HUseList<HInstruction*>::iterator before_use_node = input_use.GetBeforeUseNode();
+ DCHECK(input_use.GetInstruction() != replacement);
+ // Note: fixup_end remains valid across splice_after().
+ auto fixup_end =
+ replacement->uses_.empty() ? replacement->uses_.begin() : ++replacement->uses_.begin();
+ replacement->uses_.splice_after(replacement->uses_.before_begin(),
+ input_use.GetInstruction()->uses_,
+ before_use_node);
+ replacement->FixUpUserRecordsAfterUseInsertion(fixup_end);
+ input_use.GetInstruction()->FixUpUserRecordsAfterUseRemoval(before_use_node);
}
size_t HInstruction::EnvironmentSize() const {
diff --git a/compiler/optimizing/ssa_test.cc b/compiler/optimizing/ssa_test.cc
index 218bd53..4297634 100644
--- a/compiler/optimizing/ssa_test.cc
+++ b/compiler/optimizing/ssa_test.cc
@@ -346,7 +346,7 @@
"BasicBlock 7, pred: 6\n"
" 12: Exit\n"
"BasicBlock 8, pred: 2, 3, succ: 4\n"
- " 13: Phi(2, 1) [8, 8, 11]\n"
+ " 13: Phi(2, 1) [11, 8, 8]\n"
" 14: Goto\n";
const uint16_t data[] = ONE_REGISTER_CODE_ITEM(