[PATCH] [Polly][RTC] Bail if too many parameters are involved in an RTC access.

Johannes Doerfert doerfert at cs.uni-saarland.de
Fri Sep 26 20:09:36 PDT 2014


================
Comment at: lib/Analysis/ScopInfo.cpp:1347
@@ -1306,1 +1346,3 @@
+  isl_ctx_reset_operations(getIslCtx());
+  return Valid;
 }
----------------
grosser wrote:
> Did you find a test case that causes troubles here?
> 
> In Polly we only use the compute out to guard the dependence check, so if we reset the
> operations we should probably do this at the beginning of the dependence check, where
> we set the max operations for the compute out as well. Outside of the dependence check,
> we do not enforce a quota, so I do not really see how other passes could fail. If you have  a test case that fails here, then I probably missed something. Otherwise, I would probably leave this one out.
Yes, I'll post it tomorrow once I concluded that even the master branch breaks when the --debug flag is set.

We can postpone this patch till then though.

================
Comment at: lib/Analysis/ScopInfo.cpp:1707
@@ +1706,3 @@
+           "maximal number of parameters but be advised that the compile time "
+           "might increase exponentially.\n\n");
+
----------------
grosser wrote:
> quadratically?
My measurements indicate otherwise,.. it looks at least as if it was cubic, should I change it?

================
Comment at: test/ScopInfo/aliasing_many_parameters_not_all_involved.ll:4
@@ +3,3 @@
+;
+; Check that we allow this SCoP even though it has 10 parameters involved in posisbly aliasing accesses.
+; However, only 7 are involved in accesses through B, 8 through C and none in accesses through A.
----------------
grosser wrote:
> possibly
> 
> Also, this line is longer than 80 columns, no?
> 
> 
> 
All the run lines are,... 1) Since when do we care in test cases? 2) How am I supposed to change that?

http://reviews.llvm.org/D5500






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