Reason for revert:
Code is incorrect for -0.
Original issue's description:
> [turbofan] Implement rounding of floats on x64 and ia32 without sse4.1.
>
> The implementation sets the rounding mode flag and then uses the
> cvtsd2si and cvtsi2sd instructions (convert between float and int) to do
> the rounding. Input values outside int range either don't have to be
> rounded anyways, or are rounded by calculating input + 2^52 - 2^52 for
> positive inputs, or input -2^52 + 2^52 for negative inputs. The original
> rounding mode is restored afterwards.
>
> R=titzer@chromium.org
>
> B=575379
>
> Committed: https://crrev.com/fa5d09e547abe79a8c82f780deb980c53ad78beb
> Cr-Commit-Position: refs/heads/master@{#33367}
TBR=titzer@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
Review URL: https://codereview.chromium.org/1593313010
Cr-Commit-Position: refs/heads/master@{#33369}
The implementation sets the rounding mode flag and then uses the
cvtsd2si and cvtsi2sd instructions (convert between float and int) to do
the rounding. Input values outside int range either don't have to be
rounded anyways, or are rounded by calculating input + 2^52 - 2^52 for
positive inputs, or input -2^52 + 2^52 for negative inputs. The original
rounding mode is restored afterwards.
R=titzer@chromium.org
B=575379
Review URL: https://codereview.chromium.org/1584663007
Cr-Commit-Position: refs/heads/master@{#33367}
TryTruncateFloat32ToUint64 converts a float32 to a uint64. Additionally it
provides an optional second return value which indicates whether the conversion
succeeded (i.e. float32 value was within uint64 range) or not.
I implemented the new operator on x64, arm64, and mips64. @v8-ppc-ports, can you
please take care of the ppc64 implementation of the second output?
Additionally I fixed a bug on x64 and mips64 in the implementation of
TryTruncateFloat64ToUint64. Cases where the input value was between -1 and 0
were handled incorrectly.
R=titzer@chromium.org, v8-arm-ports@googlegroups.com, v8-mips-ports@googlegroups.com
Review URL: https://codereview.chromium.org/1512023002
Cr-Commit-Position: refs/heads/master@{#32796}
This operator now provides a second output which indicates whether the conversion from float64 to uint64 was successful or not. The second output returns 0 if the conversion fails, or something else if the conversion succeeds.
The second output can be ignored, which means that the operator can be used the same as the original operator.
I implement the new operator on x64 and arm64. @v8-mips-ports and @v8-ppc-ports, can you please take care of the mips64 and ppc64 implementation of the second output?
R=titzer@chromium.org, v8-arm-ports@googlegroups.com
Review URL: https://codereview.chromium.org/1507703002
Cr-Commit-Position: refs/heads/master@{#32705}
The least significant bit of the input value may affect the result of
the conversion through rounding. We OR the least significant with the
second least significant bit to preserve it over the SHR instruction.
R=titzer@chromium.org
Review URL: https://codereview.chromium.org/1435203003
Cr-Commit-Position: refs/heads/master@{#31969}
The usage of Unique<T> throughout the TurboFan IR does not have any
advantage. There is no single point in time when they are initialized
and most use-sites looked through to the underlying Handle<T> anyways.
Also there already was a mixture of Handle<T> versus Unique<T> in the
graph and this unifies the situation to use Handle<T> everywhere.
R=bmeurer@chromium.org,titzer@chromium.org
Review URL: https://codereview.chromium.org/1314473007
Cr-Commit-Position: refs/heads/master@{#30458}
These operators compute the absolute floating point value of some
arbitrary input, and are implemented without any branches (i.e. using
vabs on arm, and andps/andpd on x86).
R=svenpanne@chromium.org
Review URL: https://codereview.chromium.org/1066393002
Cr-Commit-Position: refs/heads/master@{#27662}
Use std::numeric_limits<double>::quiet_NaN() and
std::numeric_limits<float>::quiet_NaN() instead.
Review URL: https://codereview.chromium.org/864803002
Cr-Commit-Position: refs/heads/master@{#26195}
