- 04 Mar, 2019 1 commit
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Ross McIlroy authored
BUG=v8:8801 Change-Id: I9d9d9824c6c9ad0176bbfd3723da1b578b17c256 Reviewed-on: https://chromium-review.googlesource.com/c/1495555 Commit-Queue: Ross McIlroy <rmcilroy@chromium.org> Reviewed-by:
Mythri Alle <mythria@chromium.org> Cr-Commit-Position: refs/heads/master@{#60001}
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- 29 Oct, 2018 1 commit
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Benedikt Meurer authored
For NumberMin and NumberMax we don't need to go to Float64 when the inputs are known to be in SafeInteger range, instead we can go to Word64 on 64-bit architectures. This is preliminary work for the huge DataView support, since we'll utilize NumberMax in that case to clamp the limit for the bounds check. Bug: v8:8178, v8:8383 Change-Id: I414114229c5c86b92749d30d645cedc641541ae4 Reviewed-on: https://chromium-review.googlesource.com/c/1304535Reviewed-by:
Sigurd Schneider <sigurds@chromium.org> Commit-Queue: Benedikt Meurer <bmeurer@chromium.org> Cr-Commit-Position: refs/heads/master@{#57090}
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- 01 Oct, 2018 1 commit
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Benedikt Meurer authored
Following up on the earlier work regarding redundant Smi checks in https://chromium-review.googlesource.com/c/v8/v8/+/1246181, it was noticed that the handling of the 0 and -0 and how some operations identify these is not really consistent, but was still rather ad-hoc. This change tries to unify the handling a bit by making sure that all number comparisons generally pass truncations that identify zeros, since for the number comparisons in JavaScript there's no difference between 0 and -0. In the same spirit NumberAbs and NumberToBoolean should also pass these truncations, since they also don't care about the differences between 0 and -0. Adjust NumberCeil, NumberFloor, NumberTrunc, NumberMin and NumberMax to pass along any incoming kIdentifiesZeros truncation, since these operations also don't really care whether the inputs can be -0 if the use nodes don't care. Also utilize the kIdentifiesZeros truncation for NumberModulus with Signed32 inputs, because it's kind of common to do something like `x % 2 === 0`, where it doesn't really matter whether `x % 2` would eventually produce a negative zero (since that would still be considered true for the sake of the comparison). This also adds a whole lot of tests to ensure that not only are these optimizations correct, but also that we do indeed perform them. Drive-by-fix: The `NumberAbs(x)` would incorrectly lower to just `x` for PositiveIntegerOrMinusZeroOrNaN inputs, which was obviously wrong in case of -0. This was fixed as well, and an appropriate test was added. The reason for the unification is that with the introduction of Word64 for CheckBounds (which is necessary to support large TypedArrays and DataViews) we can no longer safely pass Word32 truncations for the interesting cases, since the index might be outside the Signed32 or Unsigned32 ranges, but we still identify 0 and -0 for the sake of the bounds check, and so it's important that this is handled consistently to not regress performance on TypedArrays and DataViews accesses. Bug: v8:8015, v8:8178 Change-Id: Ia1d32f1b726754cea1e5793105d9423d84a6393a Reviewed-on: https://chromium-review.googlesource.com/1246172Reviewed-by:
Sigurd Schneider <sigurds@chromium.org> Reviewed-by:
Benedikt Meurer <bmeurer@chromium.org> Commit-Queue: Benedikt Meurer <bmeurer@chromium.org> Cr-Commit-Position: refs/heads/master@{#56325}
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