Modified: trunk/Source/_javascript_Core/ChangeLog (231153 => 231154)
--- trunk/Source/_javascript_Core/ChangeLog 2018-04-29 17:30:35 UTC (rev 231153)
+++ trunk/Source/_javascript_Core/ChangeLog 2018-04-29 23:41:55 UTC (rev 231154)
@@ -1,3 +1,20 @@
+2018-04-29 Filip Pizlo <fpi...@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-qu...@webkit.org>
Unreviewed, rolling out r231137.
Modified: trunk/Source/_javascript_Core/b3/B3Generate.cpp (231153 => 231154)
--- trunk/Source/_javascript_Core/b3/B3Generate.cpp 2018-04-29 17:30:35 UTC (rev 231153)
+++ trunk/Source/_javascript_Core/b3/B3Generate.cpp 2018-04-29 23:41:55 UTC (rev 231154)
@@ -80,7 +80,7 @@
if (shouldValidateIR())
validate(procedure);
-
+
if (procedure.optLevel() >= 2) {
reduceDoubleToFloat(procedure);
reduceStrength(procedure);
@@ -87,12 +87,7 @@
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
Modified: trunk/Source/_javascript_Core/runtime/Options.h (231153 => 231154)
--- trunk/Source/_javascript_Core/runtime/Options.h 2018-04-29 17:30:35 UTC (rev 231153)
+++ trunk/Source/_javascript_Core/runtime/Options.h 2018-04-29 23:41:55 UTC (rev 231154)
@@ -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) \
\
