r374756 - [docs] loop pragmas: options implying transformations

[Sjoerd Meijer via cfe-commits]

Author: sjoerdmeijer
Date: Mon Oct 14 00:40:36 2019
New Revision: 374756

URL: http://llvm.org/viewvc/llvm-project?rev=374756&view=rev
Log:
[docs] loop pragmas: options implying transformations

Following our discussion on the cfe dev list:
http://lists.llvm.org/pipermail/cfe-dev/2019-August/063054.html,
I have added a paragraph that is explicit about loop pragmas, and
transformation options implying the corresponding transformation.

Differential Revision: https://reviews.llvm.org/D66199

Modified:
    cfe/trunk/docs/LanguageExtensions.rst

Modified: cfe/trunk/docs/LanguageExtensions.rst
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/docs/LanguageExtensions.rst?rev=374756&r1=374755&r2=374756&view=diff
==============================================================================
--- cfe/trunk/docs/LanguageExtensions.rst (original)
+++ cfe/trunk/docs/LanguageExtensions.rst Mon Oct 14 00:40:36 2019
@@ -3027,6 +3027,14 @@ provides options for vectorization, inte
 distribution. Loop hints can be specified before any loop and will be ignored if
 the optimization is not safe to apply.
 
+There are loop hints that control transformations (e.g. vectorization, loop
+unrolling) and there are loop hints that set transformation options (e.g.
+``vectorize_width``, ``unroll_count``).  Pragmas setting transformation options
+imply the transformation is enabled, as if it was enabled via the corresponding
+transformation pragma (e.g. ``vectorize(enable)``). If the transformation is
+disabled  (e.g. ``vectorize(disable)``), that takes precedence over
+transformations option pragmas implying that transformation.
+
 Vectorization, Interleaving, and Predication
 --------------------------------------------