Optimize call sites that only ever see a single elements transition

Optimize call sites that only ever see a single elements transition


R=jkummerow@chromium.org
TEST=imaging-gaussian-blur performance improves

Committed: https://code.google.com/p/v8/source/detail?r=10683

[Jakob Kummerow, 2012-02-13 10:50:57]

LGTM with comments.

https://chromiumcodereview.appspot.com/9389001/diff/3001/src/ic.cc
File src/ic.cc (right):

https://chromiumcodereview.appspot.com/9389001/diff/3001/src/ic.cc#newcode1515
src/ic.cc:1515: // The first time there's an element transition, assume the new
Suggestion:
s/The first time there's an element transition/The first time a receiver is seen
that is a transitioned version of the previous monomorphic receiver type/
Otherwise it sounds like the transition happens at this IC here.

https://chromiumcodereview.appspot.com/9389001/diff/3001/src/ic.cc#newcode1520
src/ic.cc:1520: // support both the untransitioned and transition maps.
s/transition/transitioned/

https://chromiumcodereview.appspot.com/9389001/diff/3001/src/ic.cc#newcode1545
src/ic.cc:1545: if (ic_state == UNINITIALIZED || ic_state == PREMONOMORPHIC) {
I think we don't need this if-block anymore. Note that the same thing is done
unconditionally in the next line, and the only case where not setting the
map_added flag would make a difference (UNINITIALIZED target with
non-transitioning stub_kind) is already handled above.