Changeset 231154 in webkit for trunk/Source/JavaScriptCore/b3/B3Generate.cpp

Timestamp:

Apr 29, 2018, 4:41:55 PM (7 years ago)

Author:

[email protected]

Message:

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:

File:

• trunk/Source/JavaScriptCore/b3/B3Generate.cpp (modified) (3 diffs)

trunk/Source/JavaScriptCore/b3/B3Generate.cpp

@@ -81 +81 @@
     if (shouldValidateIR())
         validate(procedure);
-
+    
     if (procedure.optLevel() >= 2) {
         reduceDoubleToFloat(procedure);
@@ -88 +88 @@
         if (eliminateCommonSubexpressions(procedure))
             eliminateCommonSubexpressions(procedure);
-        foldPathConstants(procedure);
-        reduceStrength(procedure);
         inferSwitches(procedure);
-        duplicateTails(procedure);
-        fixSSA(procedure);
-        foldPathConstants(procedure);
         
         // FIXME: Add more optimizations here.
@@ -106 +101 @@
 
     if (procedure.optLevel() >= 2) {
+        reduceStrength(procedure);
+        if (Options::useB3TailDup())
+            duplicateTails(procedure);
+        fixSSA(procedure);
+        foldPathConstants(procedure);
         reduceStrength(procedure);