Tweak CanLoadFromObjectPool to return true even if obj.InVMHeap().

Tweak CanLoadFromObjectPool to return true even if obj.InVMHeap().

Previously it made sense to return false from this predicate because we would then load it directly as immediate.

However after r28067 we switched from movq to LoadImmediate. Now we end up putting obj.raw() into a constant pool with lowest bit masked off (to make it look like a smi) and then restoring this bit after load:

movq r10, [r15 + offs]
orq r10, 1

This orq is completely redundant - we should not clear off the least significant bit in the first place.

BUG=
R=zra@google.com

Committed: https://code.google.com/p/dart/source/detail?r=42877

[Vyacheslav Egorov (Google), 2015-01-14 17:17:11]

vegorov@google.com changed reviewers:
+ zra@google.com

[Vyacheslav Egorov (Google), 2015-01-14 17:17:12]

PTAL

[zra, 2015-01-14 17:53:25]

lgtm

https://codereview.chromium.org/849093002/diff/1/runtime/vm/assembler_arm64.cc
File runtime/vm/assembler_arm64.cc (right):

https://codereview.chromium.org/849093002/diff/1/runtime/vm/assembler_arm64.c...
runtime/vm/assembler_arm64.cc:569: object.InVMHeap());
Don't need this anymore, I think.

https://codereview.chromium.org/849093002/diff/1/runtime/vm/assembler_x64.cc
File runtime/vm/assembler_x64.cc (right):

https://codereview.chromium.org/849093002/diff/1/runtime/vm/assembler_x64.cc#...
runtime/vm/assembler_x64.cc:2870: object.InVMHeap());
I don't think we need object.InVMHeap() here anymore, then.

https://codereview.chromium.org/849093002/diff/1/runtime/vm/compiler.cc
File runtime/vm/compiler.cc (right):

https://codereview.chromium.org/849093002/diff/1/runtime/vm/compiler.cc#newco...
runtime/vm/compiler.cc:855: if (!object_pool.IsNull() && object_pool.Length() >
0) {
(object_pool.Length() > 0)

[Vyacheslav Egorov (Google), 2015-01-14 17:56:33]

https://codereview.chromium.org/849093002/diff/1/runtime/vm/assembler_arm64.cc
File runtime/vm/assembler_arm64.cc (right):

https://codereview.chromium.org/849093002/diff/1/runtime/vm/assembler_arm64.c...
runtime/vm/assembler_arm64.cc:569: object.InVMHeap());
On 2015/01/14 17:53:24, zra wrote:
> Don't need this anymore, I think.

It still falls down here if !allow_constant_pool() so we better have an
assertion that it is safe to embed raw pointer like that.

https://codereview.chromium.org/849093002/diff/1/runtime/vm/assembler_x64.cc
File runtime/vm/assembler_x64.cc (right):

https://codereview.chromium.org/849093002/diff/1/runtime/vm/assembler_x64.cc#...
runtime/vm/assembler_x64.cc:2870: object.InVMHeap());
On 2015/01/14 17:53:24, zra wrote:
> I don't think we need object.InVMHeap() here anymore, then.

Ditto

https://codereview.chromium.org/849093002/diff/1/runtime/vm/compiler.cc
File runtime/vm/compiler.cc (right):

https://codereview.chromium.org/849093002/diff/1/runtime/vm/compiler.cc#newco...
runtime/vm/compiler.cc:855: if (!object_pool.IsNull() && object_pool.Length() >
0) {
On 2015/01/14 17:53:24, zra wrote:
> (object_pool.Length() > 0)

Done.

[Vyacheslav Egorov (Google), 2015-01-14 17:57:54]

Committed patchset #1 (id:1) manually as 42877 (presubmit successful).