B3 should run tail duplication at the bitter end
https://bugs.webkit.org/show_bug.cgi?id=185123
Reviewed by Geoffrey Garen.
Also added an option to disable taildup. This appears to be a 1% AsmBench speed-up. It's neutral
everywhere else.
The goal of this change is to allow us to run path specialization after switch lowering but
before tail duplication.
* b3/B3Generate.cpp:
(JSC::B3::generateToAir):
* runtime/Options.h:
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@231154 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/Source/JavaScriptCore/ChangeLog b/Source/JavaScriptCore/ChangeLog
index c38034d..4d0f8b5 100644
--- a/Source/JavaScriptCore/ChangeLog
+++ b/Source/JavaScriptCore/ChangeLog
@@ -1,3 +1,20 @@
+2018-04-29 Filip Pizlo <fpizlo@apple.com>
+
+ B3 should run tail duplication at the bitter end
+ https://bugs.webkit.org/show_bug.cgi?id=185123
+
+ Reviewed by Geoffrey Garen.
+
+ Also added an option to disable taildup. This appears to be a 1% AsmBench speed-up. It's neutral
+ everywhere else.
+
+ The goal of this change is to allow us to run path specialization after switch lowering but
+ before tail duplication.
+
+ * b3/B3Generate.cpp:
+ (JSC::B3::generateToAir):
+ * runtime/Options.h:
+
2018-04-29 Commit Queue <commit-queue@webkit.org>
Unreviewed, rolling out r231137.
diff --git a/Source/JavaScriptCore/b3/B3Generate.cpp b/Source/JavaScriptCore/b3/B3Generate.cpp
index 975ba66..c498345 100644
--- a/Source/JavaScriptCore/b3/B3Generate.cpp
+++ b/Source/JavaScriptCore/b3/B3Generate.cpp
@@ -80,19 +80,14 @@
if (shouldValidateIR())
validate(procedure);
-
+
if (procedure.optLevel() >= 2) {
reduceDoubleToFloat(procedure);
reduceStrength(procedure);
hoistLoopInvariantValues(procedure);
if (eliminateCommonSubexpressions(procedure))
eliminateCommonSubexpressions(procedure);
- foldPathConstants(procedure);
- reduceStrength(procedure);
inferSwitches(procedure);
- duplicateTails(procedure);
- fixSSA(procedure);
- foldPathConstants(procedure);
// FIXME: Add more optimizations here.
// https://bugs.webkit.org/show_bug.cgi?id=150507
@@ -106,6 +101,11 @@
if (procedure.optLevel() >= 2) {
reduceStrength(procedure);
+ if (Options::useB3TailDup())
+ duplicateTails(procedure);
+ fixSSA(procedure);
+ foldPathConstants(procedure);
+ reduceStrength(procedure);
// FIXME: Add more optimizations here.
// https://bugs.webkit.org/show_bug.cgi?id=150507
diff --git a/Source/JavaScriptCore/runtime/Options.h b/Source/JavaScriptCore/runtime/Options.h
index b3e7954..5dfc8aa 100644
--- a/Source/JavaScriptCore/runtime/Options.h
+++ b/Source/JavaScriptCore/runtime/Options.h
@@ -437,6 +437,7 @@
v(bool, airRandomizeRegs, false, Normal, nullptr) \
v(bool, coalesceSpillSlots, true, Normal, nullptr) \
v(bool, logAirRegisterPressure, false, Normal, nullptr) \
+ v(bool, useB3TailDup, true, Normal, nullptr) \
v(unsigned, maxB3TailDupBlockSize, 3, Normal, nullptr) \
v(unsigned, maxB3TailDupBlockSuccessors, 3, Normal, nullptr) \
\
