[Local] Make DoesKMove required for combineMetadata.

This patch makes the DoesKMove argument non-optional, to force people
to think about it. Most cases where it is false are either code hoisting
or code sinking, where we pick one instruction from a set of
equal instructions among different code paths.

Reviewers: dberlin, nlopes, efriedma, davide

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D47475

llvm-svn: 340606
diff --git a/llvm/lib/Transforms/Scalar/JumpThreading.cpp b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
index 7b738fd..45e73e9 100644
--- a/llvm/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
@@ -1300,7 +1300,7 @@
 
     if (IsLoadCSE) {
       LoadInst *NLoadI = cast<LoadInst>(AvailableVal);
-      combineMetadataForCSE(NLoadI, LoadI);
+      combineMetadataForCSE(NLoadI, LoadI, false);
     };
 
     // If the returned value is the load itself, replace with an undef. This can
@@ -1490,7 +1490,7 @@
   }
 
   for (LoadInst *PredLoadI : CSELoads) {
-    combineMetadataForCSE(PredLoadI, LoadI);
+    combineMetadataForCSE(PredLoadI, LoadI, true);
   }
 
   LoadI->replaceAllUsesWith(PN);