Issue 9177001: Optimize simple constant cases for bitwise &,

Keyboard Shortcuts

	File
u :	up to issue
j / k :	jump to file after / before current file
J / K :	jump to next file with a comment after / before current file
	Side-by-side diff
i :	toggle intra-line diffs
e :	expand all comments
c :	collapse all comments
s :	toggle showing all comments
n / p :	next / previous diff chunk or comment
N / P :	next / previous comment
<Up> / <Down> :	next / previous line

	Issue
u :	up to list of issues
j / k :	jump to patch after / before current patch
o / <Enter> :	open current patch in side-by-side view
i :	open current patch in unified diff view

	Issue List
j / k :	jump to issue after / before current issue
o / <Enter> :	open current issue

Issue 9177001: Optimize simple constant cases for bitwise &, | and ^. (Closed)

Created:
8 years, 11 months ago by fschneider

Modified:
8 years, 11 months ago

Reviewers:
Sven Panne

CC:
v8-dev

Base URL:
http://v8.googlecode.com/svn/branches/bleeding_edge/

Visibility:
Public.

More Reviews

Description

Optimize simple constant cases for bitwise &, | and ^. For integer bitwise operations we can replace x & -1 with x, x | 0 with x and x ^ 0 with x. Committed: http://code.google.com/p/v8/source/detail?r=10382

Patch Set 1 #

Patch Set 2 : '' #

Total comments: 4

Patch Set 3 : '' #

Created: 8 years, 11 months ago

Download [raw] [tar.bz2]

		Unified diffs	Side-by-side diffs	Delta from patch set	Stats (+20 lines, -0 lines)			Patch
	M	src/hydrogen-instructions.h	View		1 chunk	+2 lines, -0 lines	0 comments	Download
	M	src/hydrogen-instructions.cc	View	1 2	1 chunk	+18 lines, -0 lines	0 comments	Download

Messages

Total messages: 3 (0 generated)

Expand Messages | Collapse Messages

Sven Panne

LGTM with 2 nits... http://codereview.chromium.org/9177001/diff/4001/src/hydrogen-instructions.cc File src/hydrogen-instructions.cc (right): http://codereview.chromium.org/9177001/diff/4001/src/hydrogen-instructions.cc#newcode793 src/hydrogen-instructions.cc:793: if (op() == Token::BIT_XOR) return ...

8 years, 11 months ago (2012-01-11 09:54:03 UTC) #2

fschneider

8 years, 11 months ago (2012-01-11 10:00:30 UTC) #3

http://codereview.chromium.org/9177001/diff/4001/src/hydrogen-instructions.cc
File src/hydrogen-instructions.cc (right):

http://codereview.chromium.org/9177001/diff/4001/src/hydrogen-instructions.cc...
src/hydrogen-instructions.cc:793: if (op() == Token::BIT_XOR) return this;
On 2012/01/11 09:54:03, Sven wrote:
> I don't think we need this special case, because 'x ^ 0 == x', just like 'x |
0
> == x'.

Done.

http://codereview.chromium.org/9177001/diff/4001/src/hydrogen-instructions.cc...
src/hydrogen-instructions.cc:795: int nop_constant = (op() == Token::BIT_AND) ?
-1 : 0;
On 2012/01/11 09:54:03, Sven wrote:
> Use int32_t, not int.

Done.

Expand Messages | Collapse Messages