Bug 21803

Summary:

Fuse op_jfalse with op_eq_null and op_neq_null

Product:

WebKit

Reporter:

Cameron Zwarich (cpst) <zwarich>

Component:

JavaScriptCore

Assignee:

Cameron Zwarich (cpst) <zwarich>

Status:

RESOLVED FIXED

Severity:

Normal

Priority:

Version:

528+ (Nightly build)

Hardware:

All

OS:

All

Bug Depends on:

Bug Blocks:

20813

Attachments:

Description	Flags
Proposed patch	ggaren: review+

Description Cameron Zwarich (cpst) 2008-10-22 10:50:27 PDT

Branches of the form

if (a == null) ...

and

if (a != null) ...

are common on the V8 Richards benchmark. We should create new opcodes that fuse these instructions.

Comment 1 Cameron Zwarich (cpst) 2008-10-22 13:24:17 PDT

Created attachment 24568 [details]
Proposed patch

Comment 2 Geoffrey Garen 2008-10-22 13:55:13 PDT

Comment on attachment 24568 [details]
Proposed patch

 3054         /* jneq_null cond(r) target(offset)
 3036         /* jeq_null cond(r) target(offset)

Let's call "cond" "src", like you suggested.

Seems like we might get a little speedup out of experimenting with the asm a little, but this looks good.

r=me

Comment 3 Cameron Zwarich (cpst) 2008-10-22 14:07:01 PDT

Landed in r37789.