Extended Subgroups (KhronosGroup#529)

* initial version for publication

* add version information

* clarify undefined behavior for non-uniform broadcast and inverse ballot
document supported types for subgroup mask built-ins

* update version information

* Apply suggestions from code review

OpenCL_Ext.txt

@@ -82,6 +82,8 @@ include::ext/cl_khr_async_work_group_copy_fence.asciidoc[]
 include::ext/cl_khr_device_uuid.asciidoc[]
 include::ext/cl_khr_extended_versioning.asciidoc[]
 
+include::ext/cl_khr_subgroup_extensions.asciidoc[]
+
 // NOTE: To keep meaningful section numbers, new
 // extension documents should be added above here!
 

env/extensions.asciidoc

@@ -180,6 +180,139 @@ If the OpenCL environment supports the extension `cl_khr_spirv_no_integer_wrap_d
 
 If the OpenCL environment supports the extension `cl_khr_spirv_no_integer_wrap_decoration` and use of the SPIR-V extension `SPV_KHR_no_integer_wrap_decoration` is declared in the module via *OpExtension*, then the environment must accept modules that include the *NoSignedWrap* or *NoUnsignedWrap* decorations.
 
+==== `cl_khr_subgroup_extended_types`
+
+If the OpenCL environment supports the extension `cl_khr_subgroup_extended_types`, then additional types are valid for the following for *Groups* instructions with _Scope_ for _Execution_ equal to *Subgroup*:
+
+* *OpGroupBroadcast*
+* *OpGroupIAdd*, *OpGroupFAdd*
+* *OpGroupSMin*, *OpGroupUMin*, *OpGroupFMin*
+* *OpGroupSMax*, *OpGroupUMax*, *OpGroupFMax*
+
+For these instructions, valid types for _Value_ are:
+
+* Scalars of supported types:
+** *OpTypeInt* (equivalent to `char`, `uchar`, `short`, `ushort`, `int`, `uint`, `long`, and `ulong`)
+** *OpTypeFloat* (equivalent to `half`, `float`, and `double`)
+
+Additionally, for *OpGroupBroadcast*, valid types for _Value_ are:
+
+* *OpTypeVectors* with 2, 3, 4, 8, or 16 _Component Count_ components of supported types:
+** *OpTypeInt* (equivalent to `char__n__`, `uchar__n__`, `short__n__`, `ushort__n__`, `int__n__`, `uint__n__`, `long__n__`, and `ulong__n__`)
+** *OpTypeFloat* (equivalent to `half__n__`, `float__n__`, and `double__n__`)
+
+==== `cl_khr_subgroup_non_uniform_vote`
+
+If the OpenCL environment supports the extension `cl_khr_subgroup_non_uniform_vote`, then the environment must accept SPIR-V modules that declare the following SPIR-V capabilities:
+
+* *GroupNonUniform*
+* *GroupNonUniformVote*
+
+For instructions requiring these capabilities, _Scope_ for _Execution_ may be:
+
+* *Subgroup*
+
+For the instruction *OpGroupNonUniformAllEqual*, valid types for _Value_ are:
+
+* Scalars of supported types:
+** *OpTypeInt* (equivalent to `char`, `uchar`, `short`, `ushort`, `int`, `uint`, `long`, and `ulong`)
+** *OpTypeFloat* (equivalent to `half`, `float`, and `double`)
+
+==== `cl_khr_subgroup_ballot`
+
+If the OpenCL environment supports the extension `cl_khr_subgroup_ballot`, then the environment must accept SPIR-V modules that declare the following SPIR-V capabilities:
+
+* *GroupNonUniformBallot*
+
+For instructions requiring these capabilities, _Scope_ for _Execution_ may be:
+
+* *Subgroup*
+
+For the non-uniform broadcast instruction *OpGroupNonUniformBroadcast*, valid types for _Value_ are:
+
+* Scalars of supported types:
+** *OpTypeInt* (equivalent to `char`, `uchar`, `short`, `ushort`, `int`, `uint`, `long`, and `ulong`)
+** *OpTypeFloat* (equivalent to `half`, `float`, and `double`)
+* *OpTypeVectors* with 2, 3, 4, 8, or 16 _Component Count_ components of supported types:
+** *OpTypeInt* (equivalent to `char__n__`, `uchar__n__`, `short__n__`, `ushort__n__`, `int__n__`, `uint__n__`, `long__n__`, and `ulong__n__`)
+** *OpTypeFloat* (equivalent to `half__n__`, `float__n__`, and `double__n__`)
+
+For the instruction *OpGroupNonUniformBroadcastFirst*, valid types for _Value_ are:
+
+* Scalars of supported types:
+** *OpTypeInt* (equivalent to `char`, `uchar`, `short`, `ushort`, `int`, `uint`, `long`, and `ulong`)
+** *OpTypeFloat* (equivalent to `half`, `float`, and `double`)
+
+For the instruction *OpGroupNonUniformBallot*, the valid _Result Type_ is an *OpTypeVector* with four _Component Count_ components of *OpTypeInt*, with _Width_ equal to 32 and _Signedness_ equal to 0 (equivalent to `uint4`).
+
+For the instructions *OpGroupNonUniformInverseBallot*, *OpGroupNonUniformBallotBitExtract*, *OpGroupNonUniformBallotBitCount*, *OpGroupNonUniformBallotFindLSB*, and *OpGroupNonUniformBallotFindMSB*, the valid type for _Value_ is an *OpTypeVector* with four _Component Count_ components of *OpTypeInt*, with _Width_ equal to 32 and _Signedness_ equal to 0 (equivalent to `uint4`).
+
+For built-in variables decorated with *SubgroupEqMask*, *SubgroupGeMask*, *SubgroupGtMask*, *SubgroupLeMask*, or *SubgroupLtMask*, the supported variable type is an *OpTypeVector* with four _Component Count_ components of *OpTypeInt*, with _Width_ equal to 32 and _Signedness_ equal to 0 (equivalent to `uint4`).
+
+==== `cl_khr_subgroup_non_uniform_arithmetic`
+
+If the OpenCL environment supports the extension `cl_khr_subgroup_non_uniform_arithmetic`, then the environment must accept SPIR-V modules that declare the following SPIR-V capabilities:
+
+* *GroupNonUniformArithmetic*
+
+For instructions requiring these capabilities, _Scope_ for _Execution_ may be:
+
+* *Subgroup*
+
+For the instructions *OpGroupNonUniformLogicalAnd*, *OpGroupNonUniformLogicalOr*, and *OpGroupNonUniformLogicalXor*, the valid type for _Value_ is *OpTypeBool*.
+
+Otherwise, for the *GroupNonUniformArithmetic* scan and reduction instructions, valid types for _Value_ are:
+
+* Scalars of supported types:
+** *OpTypeInt* (equivalent to `char`, `uchar`, `short`, `ushort`, `int`, `uint`, `long`, and `ulong`)
+** *OpTypeFloat* (equivalent to `half`, `float`, and `double`)
+
+For the *GroupNonUniformArithmetic* scan and reduction instructions, the optional _ClusterSize_ operand must not be present.
+
+==== `cl_khr_subgroup_shuffle`
+
+If the OpenCL environment supports the extension `cl_khr_subgroup_shuffle`, then the environment must accept SPIR-V modules that declare the following SPIR-V capabilities:
+
+* *GroupNonUniformShuffle*
+
+For instructions requiring these capabilities, _Scope_ for _Execution_ may be:
+
+* *Subgroup*
+
+For the instructions *OpGroupNonUniformShuffle* and *OpGroupNonUniformShuffleXor* requiring these capabilities, valid types for _Value_ are:
+
+* Scalars of supported types:
+** *OpTypeInt* (equivalent to `char`, `uchar`, `short`, `ushort`, `int`, `uint`, `long`, and `ulong`)
+** *OpTypeFloat* (equivalent to `half`, `float`, and `double`)
+
+==== `cl_khr_subgroup_shuffle_relative`
+
+If the OpenCL environment supports the extension `cl_khr_subgroup_shuffle_relative`, then the environment must accept SPIR-V modules that declare the following SPIR-V capabilities:
+
+* *GroupNonUniformShuffleRelative*
+
+For instructions requiring these capabilities, _Scope_ for _Execution_ may be:
+
+* *Subgroup*
+
+For the *GroupNonUniformShuffleRelative* instructions, valid types for _Value_ are:
+
+* Scalars of supported types:
+** *OpTypeInt* (equivalent to `char`, `uchar`, `short`, `ushort`, `int`, `uint`, `long`, and `ulong`)
+** *OpTypeFloat* (equivalent to `half`, `float`, and `double`)
+
+==== `cl_khr_subgroup_clustered_reduce`
+
+If the OpenCL environment supports the extension `cl_khr_subgroup_clustered_reduce`, then the environment must accept SPIR-V modules that declare the following SPIR-V capabilities:
+
+* *GroupNonUniformClustered*
+
+For instructions requiring these capabilities, _Scope_ for _Execution_ may be:
+
+* *Subgroup*
+
+When the *GroupNonUniformClustered* capability is declared, the *GroupNonUniformArithmetic* scan and reduction instructions may include the optional _ClusterSize_ operand.
+
 === Embedded Profile Extensions
 
 ==== `cles_khr_int64`