This allows to replace redundant LoadField's whose type doesn't match
the type of the replacement, by just turning those LoadField's into
TypeGuard's.
Bug: v8:8070
Change-Id: Ia329bb536f8829be27e070e90e9eaae0618dac7a
Reviewed-on: https://chromium-review.googlesource.com/1188131
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55407}
This avoid introduction of {TypeGuard} nodes during load elimination.
Such type guard could lead to contradicting type information where a
constant {NumberConstant} node was guarded to have {ExternalPointer}
type, which would lead to an impossible constraint on representation
selection.
R=jarin@chromium.org
TEST=mjsunit/regress/regress-crbug-752826
BUG=chromium:752826
Change-Id: Ida3815af24ccc8a48474b8d66117b9718f61adda
Reviewed-on: https://chromium-review.googlesource.com/605547
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47218}
This gives us more precise type information, so we can avoid some type
guards to refine the type information back.
The motivation for this is to help escape analysis by not introducing
redundant type guards (which escape analysis cannot handle yet even
though it could and should do).
Motivating example:
In the example below, the out-of-object property array for properties
fld5 and fld6 gets type Any when it is created by "o.fld5 = 5" (for
object literals, we store 4 properties in-objeca, the rest goes out
of object).
When we run load elimination for the load the out-of-object property
array (to store 6 into o.fld6), load elimination inserts TypeGuard to
enforce the Type::Internal() type. This makes escape analysis bail out
on this object, and we do not eliminate the object creation.
function f() {
var o = {};
o.fld1 = 1;
o.fld2 = 2;
o.fld3 = 3;
o.fld4 = 4;
o.fld5 = 5;
o.fld6 = 6;
}
f();
f();
%OptimizeFunctionOnNextCall(f);
f();
Review-Url: https://codereview.chromium.org/2797993006
Cr-Commit-Position: refs/heads/master@{#44470}
KillFields of an object should remove its cache from all the fields.
Currently, the cache in the front field is kept which is not expected.
This patch fixes it.
Review-Url: https://codereview.chromium.org/2618273002
Cr-Commit-Position: refs/heads/master@{#42388}
Hook up TurboFan with the existing field type tracking machinery to
eliminate redundant map checks on the results of LoadField operators.
The store side is already implemented in TurboFan for quite some time,
this just adds the load part.
R=jarin@chromium.org
BUG=v8:5267
Review-Url: https://codereview.chromium.org/2604393002
Cr-Commit-Position: refs/heads/master@{#42015}
For two FinishRegion nodes, the alias analysis returned "may alias" even
without properly looking through them.
Drive-by-fix: Add meaningful output for --trace-turbo-load-elimination.
R=jarin@chromium.org
BUG=v8:5267
Review-Url: https://codereview.chromium.org/2301903002
Cr-Commit-Position: refs/heads/master@{#39075}
If the type of a tracked field or element value is less precise than the
advertised type of the field or element load, then we replace the load
operation with a TypeGuard that guards the advertised type.
R=jarin@chromium.org
BUG=v8:5267
Review-Url: https://codereview.chromium.org/2295643002
Cr-Commit-Position: refs/heads/master@{#39032}
This introduces appropriate unit tests to ensure that merging of
elements/fields information is correct for diamonds.
BUG=chromium:639210,v8:5266
R=jarin@chromium.org
Review-Url: https://codereview.chromium.org/2278043002
Cr-Commit-Position: refs/heads/master@{#38881}
This extends JSNativeContextSpecialization with support for stores to
fast object/smi element backing stores that are marked as copy-on-write.
In this case we first call the CopyFixedArray builtin to take a copy of
the elements backing store, and then store the new elements back to the
object, and finally perform the actual element store.
R=epertoso@chromium.org
BUG=v8:4470
Committed: https://crrev.com/ac98ad22f049a59c48387f1bab1590f135d219c6
Review-Url: https://codereview.chromium.org/2218703003
Cr-Original-Commit-Position: refs/heads/master@{#38370}
Cr-Commit-Position: refs/heads/master@{#38392}
Reason for revert:
Breaks tree?
Original issue's description:
> [turbofan] Add support for copy-on-write element stores.
>
> This extends JSNativeContextSpecialization with support for stores to
> fast object/smi element backing stores that are marked as copy-on-write.
> In this case we first call the CopyFixedArray builtin to take a copy of
> the elements backing store, and then store the new elements back to the
> object, and finally perform the actual element store.
>
> R=epertoso@chromium.org
> BUG=v8:4470
>
> Committed: https://crrev.com/ac98ad22f049a59c48387f1bab1590f135d219c6
> Cr-Commit-Position: refs/heads/master@{#38370}
TBR=epertoso@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4470
Review-Url: https://codereview.chromium.org/2220513002
Cr-Commit-Position: refs/heads/master@{#38376}
This extends JSNativeContextSpecialization with support for stores to
fast object/smi element backing stores that are marked as copy-on-write.
In this case we first call the CopyFixedArray builtin to take a copy of
the elements backing store, and then store the new elements back to the
object, and finally perform the actual element store.
R=epertoso@chromium.org
BUG=v8:4470
Review-Url: https://codereview.chromium.org/2218703003
Cr-Commit-Position: refs/heads/master@{#38370}
Turn the LoadElimination into a proper graph Reducer so that it can run
together with ValueNumbering and RedundancyElimination to a fixpoint
for maximum load/check elimination. This also adds initial support for
eliminating redundant LoadElement/StoreElement nodes.
BUG=v8:4930,v8:5141
Review-Url: https://codereview.chromium.org/2164253002
Cr-Commit-Position: refs/heads/master@{#38015}
This adds a new optimization phase to the TurboFan pipeline, which walks
over the effect chain and tries to eliminate redundant loads (and even
some stores) of object fields. We currently ignore element access, but
that will probably need to be handled as well at some point. We also
don't have any special treatment to properly track object maps, which is
also on the list of things that will happen afterwards.
The implementation is pretty simple currently, and probably way to
inefficient. It's meant to be a proof-of-concept to iterate on.
R=jarin@chromium.org
BUG=v8:4930,v8:5141
Review-Url: https://codereview.chromium.org/2120253002
Cr-Commit-Position: refs/heads/master@{#37528}
The type guard should never be used after the effect/control
linearization pass, so making it a simplified operator better
expresses the intended use. Also this way none of the common
operators actually has any dependency on the type system.
Drive-by-fix: Properly print the type parameter to a TypeGuard operator.
BUG=chromium:612142
R=jarin@chromium.org
Review-Url: https://codereview.chromium.org/1994503002
Cr-Commit-Position: refs/heads/master@{#36304}
In simplified numbering, we make sanity checks based on types (e.g.,
NumberSubtract should take numbers as inputs), but this can be
violated if optimization passes make types less precise.
In this CL, we fix load elimination to make sure that types are
smaller in the store -> load elimination by taking an intersection
of the load's type with the store value's type and inserting a guard
with that type. Note that the load type comes from type feedback, so
it can be disjoint from the stored value type (in that case, this
must be dead code because the map chack for the load should prevent
us from using the stored value).
BUG=chromium:599412
LOG=n
Review URL: https://codereview.chromium.org/1857133003
Cr-Commit-Position: refs/heads/master@{#35259}
This is an initial version of redundant load elimination, currently
limited to LoadField operators, and implemented by walking the effect
chain.
TEST=unittests
R=svenpanne@chromium.org
Review URL: https://codereview.chromium.org/782473002
Cr-Commit-Position: refs/heads/master@{#25673}
