[Transforms] Change std::sort to llvm::sort in response to r327219

Summary:
r327219 added wrappers to std::sort which randomly shuffle the container before sorting.
This will help in uncovering non-determinism caused due to undefined sorting
order of objects having the same key.

To make use of that infrastructure we need to invoke llvm::sort instead of std::sort.

Note: This patch is one of a series of patches to replace *all* std::sort to llvm::sort.
Refer the comments section in D44363 for a list of all the required patches.

Reviewers: kcc, pcc, danielcdh, jmolloy, sanjoy, dberlin, ruiu

Reviewed By: ruiu

Subscribers: ruiu, llvm-commits

Differential Revision: https://reviews.llvm.org/D45142

llvm-svn: 330059
diff --git a/llvm/lib/Transforms/Scalar/MergeICmps.cpp b/llvm/lib/Transforms/Scalar/MergeICmps.cpp
index 0bfa254..5635f54 100644
--- a/llvm/lib/Transforms/Scalar/MergeICmps.cpp
+++ b/llvm/lib/Transforms/Scalar/MergeICmps.cpp
@@ -439,10 +439,10 @@
 #endif  // MERGEICMPS_DOT_ON
   // Reorder blocks by LHS. We can do that without changing the
   // semantics because we are only accessing dereferencable memory.
-  std::sort(Comparisons_.begin(), Comparisons_.end(),
-            [](const BCECmpBlock &a, const BCECmpBlock &b) {
-              return a.Lhs() < b.Lhs();
-            });
+  llvm::sort(Comparisons_.begin(), Comparisons_.end(),
+             [](const BCECmpBlock &a, const BCECmpBlock &b) {
+               return a.Lhs() < b.Lhs();
+             });
 #ifdef MERGEICMPS_DOT_ON
   errs() << "AFTER REORDERING:\n\n";
   dump();