Name Strings

SPV_INTEL_fp_max_error

Contact

To report problems with this extension, please open a new issue at:

https://github.com/KhronosGroup/SPIRV-Registry

Contributors

  • Shuo Niu, Intel

  • Daniel Zhang, Intel

Notice

Copyright (c) 2023 Intel Corporation. All rights reserved.

Status

Final draft

Version

Last Modified Date

2023-03-29

Revision

1

Dependencies

This extension is written against the SPIR-V Specification, Version 1.6 Revision 2.

This extension requires SPIR-V 1.0.

Overview

This extension adds a decoration that may be attached to any instruction of floating-point type. It can be used to express the maximum acceptable relative error in the result of that instruction, in ULPs.

Note that this takes precedence over accuracy requirements from the environment specification. Please refer to the client environment specification for the list of instruction that the decoration can be attached to. The client environment specification will also provide a list of valid values for the maximum acceptable relative error.

Extension Name

To use this extension within a SPIR-V module, the following OpExtension must be present in the module:

OpExtension "SPV_INTEL_fp_max_error"

New capabilities

This extension introduces a new capability:

FPMaxErrorINTEL

New Decorations

This extension adds the following decoration under the FPMaxErrorINTEL capability:

FPMaxErrorDecorationINTEL

Token Number Assignments

FPMaxErrorINTEL

6169

FPMaxErrorDecorationINTEL

6170

Modifications to the SPIR-V Specification, Version 1.6

Decoration

Modify Section 3.20, Decoration, adding the following row to the Decoration table:

Decoration Extra Operands Enabling Capabilities

6170

FPMaxErrorDecorationINTEL
Apply to a floating-point instruction to express the maximum acceptable relative error in the result of that instruction, in ULPs. ULP is defined as follows:

If x is a real number that lies between two finite consecutive floating-point numbers a and b, without being equal to one of them, then ulp(x) = |b - a|, otherwise ulp(x) is the distance between the two non-equal finite floating-point numbers nearest to x. Moreover, ulp(NaN) is NaN. To give attribution, this description referenced Jean-Michel Muller’s definition of ulp(x) with slight clarification for behaviour at zero. For details, please refer to https://hal.inria.fr/inria-00070503/document.

Max Error is a positive 32-bit float type number representing the maximum acceptable relative error.

Note that this decoration can increase or decrease allowable error. It overrides the accuracy from the environment specification and allows both the expressions of additional error and/or less error when it differs from the environment specification.

Literal
Max Error

FPMaxErrorINTEL

Capability

Modify Section 3.31, Capability, adding a row to the Capability table:

Capability Implicitly Declares

6169

FPMaxErrorINTEL

Validation Rules

None.

Issues

None.

Revision History

Rev Date Author Changes

1

2023-03-29

Shuo Niu

Initial public release