Refactor handling of input records.
Introduce HInstruction::GetInputRecords(), a new virtual
function that returns an ArrayRef<> to all input records.
Implement all other functions dealing with input records as
wrappers around GetInputRecords(). Rewrite functions that
previously used multiple virtual calls to deal with input
records, especially in loops, to prefetch the ArrayRef<>
only once for each instruction. Besides avoiding all the
extra calls, this also allows the compiler (clang++) to
perform additional optimizations.
This speeds up the Nexus 5 boot image compilation by ~0.5s
(4% of "Compile Dex File", 2% of dex2oat time) on AOSP ToT.
Change-Id: Id8ebe0fb9405e38d918972a11bd724146e4ca578
diff --git a/compiler/optimizing/ssa_phi_elimination.cc b/compiler/optimizing/ssa_phi_elimination.cc
index c67612e..b1ec99a 100644
--- a/compiler/optimizing/ssa_phi_elimination.cc
+++ b/compiler/optimizing/ssa_phi_elimination.cc
@@ -67,8 +67,8 @@
while (!worklist_.empty()) {
HPhi* phi = worklist_.back();
worklist_.pop_back();
- for (HInputIterator it(phi); !it.Done(); it.Advance()) {
- HPhi* input = it.Current()->AsPhi();
+ for (HInstruction* raw_input : phi->GetInputs()) {
+ HPhi* input = raw_input->AsPhi();
if (input != nullptr && input->IsDead()) {
// Input is a dead phi. Revive it and add to the worklist. We make sure
// that the phi was not dead initially (see definition of `initially_live`).
@@ -102,9 +102,7 @@
}
}
// Remove the phi from use lists of its inputs.
- for (size_t i = 0, e = phi->InputCount(); i < e; ++i) {
- phi->RemoveAsUserOfInput(i);
- }
+ phi->RemoveAsUserOfAllInputs();
// Remove the phi from environments that use it.
for (const HUseListNode<HEnvironment*>& use : phi->GetEnvUses()) {
HEnvironment* user = use.GetUser();
@@ -159,8 +157,7 @@
bool irreducible_loop_phi_in_cycle = phi->IsIrreducibleLoopHeaderPhi();
// First do a simple loop over inputs and check if they are all the same.
- for (size_t j = 0; j < phi->InputCount(); ++j) {
- HInstruction* input = phi->InputAt(j);
+ for (HInstruction* input : phi->GetInputs()) {
if (input == phi) {
continue;
} else if (candidate == nullptr) {
@@ -181,8 +178,7 @@
DCHECK(!current->IsLoopHeaderPhi() ||
current->GetBlock()->IsLoopPreHeaderFirstPredecessor());
- for (size_t j = 0; j < current->InputCount(); ++j) {
- HInstruction* input = current->InputAt(j);
+ for (HInstruction* input : current->GetInputs()) {
if (input == current) {
continue;
} else if (input->IsPhi()) {