[nvptx, doc] Document predefined macros at march and mptx

Document predefined macros:
- __PTX_SM__ ,
- __PTX_ISA_VERSION_MAJOR__ and
- __PTX_ISA_VERSION_MINOR__ .

gcc/ChangeLog:

2022-03-29  Tom de Vries  <tdevries@suse.de>

	* doc/invoke.texi (march): Document __PTX_SM__.
	 (mptx): Document __PTX_ISA_VERSION_MAJOR__ and
	 __PTX_ISA_VERSION_MINOR__.

Co-Authored-By: Tobias Burnus <tobias@codesourcery.com>

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 43b7513..09715a5 100644 (file)
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -27547,6 +27547,10 @@ Generate code for the specified PTX ISA target architecture
 @samp{sm_35}, @samp{sm_53}, @samp{sm_70}, @samp{sm_75} and
 @samp{sm_80}.  The default target architecture is sm_30.
 
+This option sets the value of the preprocessor macro
+@code{__PTX_SM__}; for instance, for @samp{sm_35}, it has the value
+@samp{350}.
+
 @item -misa=@var{architecture-string}
 @opindex misa
 Alias of @option{-march=}.
@@ -27566,6 +27570,11 @@ Valid version strings include @samp{3.1}, @samp{6.0}, @samp{6.3}, and
 version is required for specified PTX ISA target architecture via
 option @option{-march=}.
 
+This option sets the values of the preprocessor macros
+@code{__PTX_ISA_VERSION_MAJOR__} and @code{__PTX_ISA_VERSION_MINOR__};
+for instance, for @samp{3.1} the macros have the values @samp{3} and
+@samp{1}, respectively.
+
 @item -mmainkernel
 @opindex mmainkernel
 Link in code for a __main kernel.  This is for stand-alone instead of