[PATCH] D20116: Add nosideeffects function attribute

[Mehdi AMINI via llvm-commits]

mehdi_amini added inline comments.

================
Comment at: docs/LangRef.rst:1404
@@ +1403,3 @@
+    This function attribute indicates that the function does not modify any
+    state that isn't accessbile from the IR (e.g. floating-point exception
+    registers).  Functions with the nosideeffects attribute can be safely
----------------
tstellarAMD wrote:
> With my original definition, I was trying to match what we already have in the .td files for intrinsics.  I've updated the definition in this patch to be:
> 
> > nosideeffects tells the optimizer that the function does not modify any
> > state that isn't accessible from the IR (e.g. floating-point exception
> > registers).
> 
> I'm not sure if this is what you were thinking, but hopefully this gives us a better starting point for discussion.
> 
> 
> 
Typo `accessbile`

Also it isn't clear how it interacts with memory. Are we only considering "non-memory" effects with this attribute? What are the side effects we want to track and what will they be used for?
Is it just about "this won't not trap or exit"?


http://reviews.llvm.org/D20116