Reviewers: Jarin, Benedikt Meurer,
Description:
[turbofan] greedy: heuristic for memory operands
When we have a memory operand (HasSpillOperand() == true), and it
doesn't need a register immediately, split in an optimal position, which
is outside the outermost possible loop - just like Linear does.
This results in some modest improvements in perf, when compared
to baseline greedy. In particular Jetstream zlib x64: 4.66%, Life
(Emscripten x64) 11%; largest regression is in AreWeFastYet x64: 8% and
Corrections (Emsccripten x32) 10%
BUG=
Please review this at https://codereview.chromium.org/1306823005/
Base URL: https://chromium.googlesource.com/v8/v8.git@master
Affected files (+6, -7 lines):
M src/compiler/greedy-allocator.cc
Index: src/compiler/greedy-allocator.cc
diff --git a/src/compiler/greedy-allocator.cc
b/src/compiler/greedy-allocator.cc
index
44f2d4f8160a4893cc3964e21fc0ecb6dd7629e5..5fdacb5e8236992e377c700f9ec9d5176fb8a7df
100644
--- a/src/compiler/greedy-allocator.cc
+++ b/src/compiler/greedy-allocator.cc
@@ -256,7 +256,7 @@ void
GreedyAllocator::SplitAndSpillRangesDefinedByMemoryOperand() {
for (size_t i = 0; i < initial_range_count; ++i) {
auto range = data()->live_ranges()[i];
if (!CanProcessRange(range)) continue;
- if (range->HasNoSpillType()) continue;
+ if (!range->HasSpillOperand()) continue;
LifetimePosition start = range->Start();
TRACE("Live range %d:%d is defined by a spill operand.\n",
@@ -273,12 +273,11 @@ void
GreedyAllocator::SplitAndSpillRangesDefinedByMemoryOperand() {
} else if (pos->pos() > range->Start().NextStart()) {
// Do not spill live range eagerly if use position that can benefit
from
// the register is too close to the start of live range.
- auto split_pos = pos->pos();
- if (data()->IsBlockBoundary(split_pos.Start())) {
- split_pos = split_pos.Start();
- } else {
- split_pos = split_pos.PrevStart().End();
- }
+ auto split_pos = GetSplitPositionForInstruction(
+ range, data()->code(), pos->pos().ToInstructionIndex());
+ split_pos =
+ FindOptimalSplitPos(range->Start().NextFullStart(), split_pos);
+
Split(range, data(), split_pos);
Spill(range);
}
--
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