[NFC][AMDGPU] Document the AMDGPU target feature defaults

Document the default for the XNACK and SRAMECC target features for code object V2-V3 and V4.

Reviewed By: kzhuravl

Differential Revision: https://reviews.llvm.org/D97598

diff --git a/llvm/docs/AMDGPUUsage.rst b/llvm/docs/AMDGPUUsage.rst
index 5177cce..9205c79 100644 (file)
--- a/llvm/docs/AMDGPUUsage.rst
+++ b/llvm/docs/AMDGPUUsage.rst
@@ -484,9 +484,13 @@ For example:
                      - ``--offload-arch``         loaded and executed in a process that has a
                                                   matching setting for SRAMECC.
 
-                                                  If not specified, generate code that can be
-                                                  loaded and executed in a process with either
-                                                  setting of SRAMECC.
+                                                  If not specified for code object V2 to V3, generate
+                                                  code that can be loaded and executed in a process
+                                                  with SRAMECC enabled.
+
+                                                  If not specified for code object V4, generate
+                                                  code that can be loaded and executed in a process
+                                                  with either setting of SRAMECC.
 
      tgsplit           ``-m[no-]tgsplit``         Enable/disable generating code that assumes
                                                   work-groups are launched in threadgroup split mode.
@@ -502,20 +506,26 @@ For example:
                      - ``--offload-arch``         loaded and executed in a process that has a
                                                   matching setting for XNACK replay.
 
-                                                  If not specified, generate code that can be
-                                                  loaded and executed in a process with either
-                                                  setting of XNACK replay.
-
-                                                  This is used for demand paging and page
-                                                  migration. If XNACK replay is enabled in
-                                                  the device, then if a page fault occurs
-                                                  the code may execute incorrectly if the
-                                                  ``xnack`` feature is not enabled. Executing
-                                                  code that has the feature enabled on a
-                                                  device that does not have XNACK replay
-                                                  enabled will execute correctly but may
-                                                  be less performant than code with the
-                                                  feature disabled.
+                                                  If not specified for code object V2 to V3, generate
+                                                  code that can be loaded and executed in a process
+                                                  with XNACK replay enabled.
+
+                                                  If not specified for code object V4, generate
+                                                  code that can be loaded and executed in a process
+                                                  with either setting of XNACK replay.
+
+                                                  XNACK replay can be used for demand paging and
+                                                  page migration. If enabled in the device, then if
+                                                  a page fault occurs the code may execute
+                                                  incorrectly unless generated with XNACK replay
+                                                  enabled, or generated for code object V4 without
+                                                  specifying XNACK replay. Executing code that was
+                                                  generated with XNACK replay enabled, or generated
+                                                  for code object V4 without specifying XNACK replay,
+                                                  on a device that does not have XNACK replay
+                                                  enabled will execute correctly but may be less
+                                                  performant than code generated for XNACK replay
+                                                  disabled.
      =============== ============================ ==================================================
 
 .. _amdgpu-target-id: