[PATCH] D11149: Fix memcheck interval ends for pointers with negative strides

[Adam Nemet]

anemet added a comment.

Is this a preexisting bug to grouping pointers?  IOW, did we handle swapping start and end like this for pointers before your change?

If this was a bug even before, we probably want to benchmark this to avoid surprises.  (In theory we could have had a case where the memchecks should have failed but did not but do after your change.)

Please also add a test for the non-constant case.

Thanks!


================
Comment at: lib/Analysis/LoopAccessAnalysis.cpp:144-147
@@ +143,6 @@
+    // expressions.
+    const SCEV *Min = SE->getUMinExpr(ScStart, ScEnd);
+    const SCEV *Max = SE->getUMaxExpr(ScStart, ScEnd);
+    ScStart = Min;
+    ScEnd = Max;
+  }
----------------
Nit: you can assign to ScStart and ScEnd directly.


http://reviews.llvm.org/D11149