Name Strings

SPV_KHR_relaxed_extended_instruction

Contact

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

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

Contributors

  • Alan Baker, Google LLC

  • Nathan Gauër, Google LLC

Notice

Copyright (c) 2024 The Khronos Group Inc. Copyright terms at http://www.khronos.org/registry/speccopyright.html

Status

  • Complete

  • Approved by the SPIR-V Working Group: 2024-04-03

  • Ratified by the Khronos Group: 2024-05-17

Version

Last Modified Date

2024-06-05

Revision

4

Dependencies

This extension is written against the SPIR-V Specification, Version 1.6 Revision 3.

This extension requires SPIR-V 1.0 or later and "SPV_KHR_non_semantic_info".

This extension interacts with "NonSemantic.Shader.DebugInfo.100" extended instruction set and "SPV_KHR_non_semantic_info".

Overview

This extension adds the ability to have forward declaration in some specific non-semantic instructions. It modifies similarly both the core SPIR-V specification and the SPV_KHR_non_semantic_info extension specification.

Modifications to the SPIR-V Specification, Version 1.6

Logical Layout of a Module

Modify section 9, modifying:

(Replace the following sentence):

All operands in all these instructions must be declared before being used.

(with):

All operands in all these instructions must be declared before being used, except when the opcode is OpExtInstWithForwardRefsKHR.

Modify section 9, modifying:

(Replace the following sentence):

This section is the first section to allow use of Non-semantic instructions with OpExtInst

(with):

This section is the first section to allow use of Non-semantic instructions with OpExtInst or OpExtInstWithForwardRefsKHR

Modifies the list of locations where a forward reference is allowed to add the following cases:

  • OpExtInstWithForwardRefsKHR can contain forward references.

Instructions

Modify Section 3.49.4, "Extension Instructions", adding one new instruction:

OpExtInstWithForwardRefsKHR

Executes an instruction in an imported set of non-semantic extended instructions.

At least one <id> operand must be a forward reference, otherwise, OpExtInst must be used.

5 + variable

4433

<id>
Result Type

Result <id>

<id>
Set

Literal
Instruction

<id>, <id>, …​
Operand 1, Operand 2, …​

Modifications to the NonSemantic.Shader.DebugInfo.100 extended instruction set, Version 1.0

Introduction

(Replace the following sentence):

  • Forward references in any instruction are disallowed.

(with):

  • Forward references in any instruction are disallowed, except as operands in OpExtInstWithForwardRefsKHR.

Binary Form

Modify the Forward references section:

(Replace the following sentence):

Forward references are not allowed, to be compliant with SPV_KHR_non_semantic_info.

(with):

Forward references are not allowed, except when the instruction allows it, and when the instruction is used with OpExtInstWithForwardRefsKHR.

Validation Rules

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

OpExtension "SPV_KHR_relaxed_extended_instruction"

Each OpExtInstWithForwardRefsKHR use must have at least one forward reference as operand.

Each extended opcode used with OpExtInstWithForwardRefsKHR must belong to a non-semantic instruction set.

Issues

Revision History

Rev Date Author Changes

1

2023-10-11

Nathan Gauër

Initial revision

2

2024-03-11

Nathan Gauër

Relaxed SPIR-V version requirements.

3

2024-05-28

Nathan Gauër

Added ratification/approval dates.

4

2024-06-05

Nathan Gauër

Add KHR to opcode name.