Missing fminimum/fmaximum vp reduction intrinsics
#64940
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dcaballe
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dcaballe
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…eductions This patch is part of a larger initiative aimed at fixing floating-point `max` and `min` operations in MLIR: https://discourse.llvm.org/t/rfc-fix-floating-point-max-and-min-operations-in-mlir/72671. Within LLVM, there are no masked reduction counterparts for vector reductions such as `fmaximum` and `fminimum`. More information can be found here: #64940 (comment). To address this issue in MLIR, where we need to generate appropriate lowerings for these cases, we employ regular non-masked intrinsics. However, we modify the input vector using the `arith.select` operation to effectively deactivate undesired elements using a "neutral mask value". The neutral mask value is the smallest possible value for the `fmaximum` reduction and the largest possible value for the `fminimum` reduction. Depends on D158618 Reviewed By: dcaballe Differential Revision: https://reviews.llvm.org/D158773
ZijunZhaoCCK
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Sep 19, 2023
…eductions This patch is part of a larger initiative aimed at fixing floating-point `max` and `min` operations in MLIR: https://discourse.llvm.org/t/rfc-fix-floating-point-max-and-min-operations-in-mlir/72671. Within LLVM, there are no masked reduction counterparts for vector reductions such as `fmaximum` and `fminimum`. More information can be found here: llvm#64940 (comment). To address this issue in MLIR, where we need to generate appropriate lowerings for these cases, we employ regular non-masked intrinsics. However, we modify the input vector using the `arith.select` operation to effectively deactivate undesired elements using a "neutral mask value". The neutral mask value is the smallest possible value for the `fmaximum` reduction and the largest possible value for the `fminimum` reduction. Depends on D158618 Reviewed By: dcaballe Differential Revision: https://reviews.llvm.org/D158773
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‘llvm.vector.reduce.fminimum.*’ and ‘llvm.vector.reduce.fmaximum.*’ have been recently added to the IR. However, there is no masked variant for them. It would be great if they could be added.
(Nit: there is also certain inconsistency with the naming of the scalar and vector reduction non-NaN propagating intrinsics. ‘llvm.minnum.*’ and ‘llvm.maxnum.*’ are used for the scalar ones and
fmin/fmaxsuffixed are used for both the predicated and non-predicated vector reduction versions. We should consider renaming them all tominnum/maxnumorfmin/fmax.)CC: @simoll, @rofirrim, @topperc, @unterumarmung
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