[llvm] [lit][docs] Mention LIT_OPTS instead of LIT_ARGS (PR #147494)

[Remy Farley via llvm-commits]

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@@ -152,15 +152,24 @@ can run the LLVM and Clang tests simultaneously using:
 
     % make check-all
 
-To run the tests with Valgrind (Memcheck by default), use the ``LIT_ARGS`` make
+To run the tests with Valgrind (Memcheck by default), use the ``LIT_OPTS`` make
 variable to pass the required options to lit. For example, you can use:
 
 .. code-block:: bash
 
-    % make check LIT_ARGS="-v --vg --vg-leak"
+    % make check LIT_OPTS="-v --vg --vg-leak"
 
 to enable testing with valgrind and with leak checking enabled.
 
+To skip the evaluation of dependencies when iterating on tests, add suffix /fast
+(automatically generated by cmake) to the make target, i.e.
+
+.. code-block:: bash
+
+    % make check/fast LIT_OPTS="--filter <...>"
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one-d-wide wrote:

Agreed.

I think I didn't notice llvm-lit in build/bin when first reading this and somehow ended up staring at executable llvm/utils/lit/lit.py which was emitting some weird python errors because it missed the configuration. So assumed calling lit directly was some kind of stand-alone/specialized while make check* was the "intended" way. My bad.

https://github.com/llvm/llvm-project/pull/147494