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Issue
172293004:
Explicit conversions for Float32 array loads/stores. (Closed)
DescriptionExplicit conversions for Float32 array loads/stores.
Added two new IL instructions: DoubleToFloat and FloatToDouble.
This enables store-to-load forwarding for Float32 arrays which was
not working before because of the implicit conversions.
Loads are now translated as:
v3 <- LoadIndexed(v2, v1)
v4 <- FloatToDouble(v3)
Stores:
v5 <- DoubleToFloat(v4)
StoreIndexed(v7, v6, v5)
There is no explicit representation for float values because
they are never used in a deoptimization environment. The only
real uses are at FloatToDouble and StoreIndexed.
For example when copying a value from one Float32 array to another
there is no intermediate conversions anymore
a[0] = b[0] before:
movss xmm1,[ebx+0x7]
cvtss2sd xmm1,xmm1
cvtsd2ss xmm2,xmm1
movss [edx+0x7],xmm2
after:
movss xmm1,[ebx+0x7]
movss [edx+0x7],xmm1
Also in this change:
Eliminate GuardField based on cid information of list factories.
GC unused symbols
R=johnmccutchan@google.com
Committed: https://code.google.com/p/dart/source/detail?r=32891
Patch Set 1 #Patch Set 2 : #
Total comments: 2
Patch Set 3 : #Patch Set 4 : fixed ARM register constraints #
Messages
Total messages: 3 (0 generated)
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