[LoopInterchange] Add remark for calls preventing interchanging.

It also updates test/Transforms/LoopInterchange/call-instructions.ll
to use accesses where we can prove dependence after D35430.


Reviewers: sebpop, karthikthecool, blitz.opensource

Reviewed By: sebpop

Differential Revision: https://reviews.llvm.org/D45206

llvm-svn: 329111

1 files changed, 7 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Scalar/LoopInterchange.cpp b/llvm/lib/Transforms/Scalar/LoopInterchange.cpp
index 69b10890d24..4d3e4563c1e 100644
--- a/llvm/lib/Transforms/Scalar/LoopInterchange.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopInterchange.cpp
@@ -985,6 +985,13 @@ bool LoopInterchangeLegality::canInterchangeLoops(unsigned InnerLoopId,
           continue;
         DEBUG(dbgs() << "Loops with call instructions cannot be interchanged "
                      << "safely.");
+        ORE->emit([&]() {
+          return OptimizationRemarkMissed(DEBUG_TYPE, "CallInst",
+                                          CI->getDebugLoc(),
+                                          CI->getParent())
+                 << "Cannot interchange loops due to call instruction.";
+        });
+
         return false;
       }