Enhance synchscope representation

  OpenCL 2.0 introduces the notion of memory scopes in atomic operations to
  global and local memory. These scopes restrict how synchronization is
  achieved, which can result in improved performance.

  This change extends existing notion of synchronization scopes in LLVM to
  support arbitrary scopes expressed as target-specific strings, in addition to
  the already defined scopes (single thread, system).

  The LLVM IR and MIR syntax for expressing synchronization scopes has changed
  to use *syncscope("<scope>")*, where <scope> can be "singlethread" (this
  replaces *singlethread* keyword), or a target-specific name. As before, if
  the scope is not specified, it defaults to CrossThread/System scope.

  Implementation details:
    - Mapping from synchronization scope name/string to synchronization scope id
      is stored in LLVM context;
    - CrossThread/System and SingleThread scopes are pre-defined to efficiently
      check for known scopes without comparing strings;
    - Synchronization scope names are stored in SYNC_SCOPE_NAMES_BLOCK in
      the bitcode.

Differential Revision: https://reviews.llvm.org/D21723

llvm-svn: 307722
diff --git a/llvm/lib/Transforms/Utils/FunctionComparator.cpp b/llvm/lib/Transforms/Utils/FunctionComparator.cpp
index 0457294..4a2be3a 100644
--- a/llvm/lib/Transforms/Utils/FunctionComparator.cpp
+++ b/llvm/lib/Transforms/Utils/FunctionComparator.cpp
@@ -513,8 +513,8 @@
     if (int Res =
             cmpOrderings(LI->getOrdering(), cast<LoadInst>(R)->getOrdering()))
       return Res;
-    if (int Res =
-            cmpNumbers(LI->getSynchScope(), cast<LoadInst>(R)->getSynchScope()))
+    if (int Res = cmpNumbers(LI->getSyncScopeID(),
+                             cast<LoadInst>(R)->getSyncScopeID()))
       return Res;
     return cmpRangeMetadata(LI->getMetadata(LLVMContext::MD_range),
         cast<LoadInst>(R)->getMetadata(LLVMContext::MD_range));
@@ -529,7 +529,8 @@
     if (int Res =
             cmpOrderings(SI->getOrdering(), cast<StoreInst>(R)->getOrdering()))
       return Res;
-    return cmpNumbers(SI->getSynchScope(), cast<StoreInst>(R)->getSynchScope());
+    return cmpNumbers(SI->getSyncScopeID(),
+                      cast<StoreInst>(R)->getSyncScopeID());
   }
   if (const CmpInst *CI = dyn_cast<CmpInst>(L))
     return cmpNumbers(CI->getPredicate(), cast<CmpInst>(R)->getPredicate());
@@ -584,7 +585,8 @@
     if (int Res =
             cmpOrderings(FI->getOrdering(), cast<FenceInst>(R)->getOrdering()))
       return Res;
-    return cmpNumbers(FI->getSynchScope(), cast<FenceInst>(R)->getSynchScope());
+    return cmpNumbers(FI->getSyncScopeID(),
+                      cast<FenceInst>(R)->getSyncScopeID());
   }
   if (const AtomicCmpXchgInst *CXI = dyn_cast<AtomicCmpXchgInst>(L)) {
     if (int Res = cmpNumbers(CXI->isVolatile(),
@@ -601,8 +603,8 @@
             cmpOrderings(CXI->getFailureOrdering(),
                          cast<AtomicCmpXchgInst>(R)->getFailureOrdering()))
       return Res;
-    return cmpNumbers(CXI->getSynchScope(),
-                      cast<AtomicCmpXchgInst>(R)->getSynchScope());
+    return cmpNumbers(CXI->getSyncScopeID(),
+                      cast<AtomicCmpXchgInst>(R)->getSyncScopeID());
   }
   if (const AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(L)) {
     if (int Res = cmpNumbers(RMWI->getOperation(),
@@ -614,8 +616,8 @@
     if (int Res = cmpOrderings(RMWI->getOrdering(),
                              cast<AtomicRMWInst>(R)->getOrdering()))
       return Res;
-    return cmpNumbers(RMWI->getSynchScope(),
-                      cast<AtomicRMWInst>(R)->getSynchScope());
+    return cmpNumbers(RMWI->getSyncScopeID(),
+                      cast<AtomicRMWInst>(R)->getSyncScopeID());
   }
   if (const PHINode *PNL = dyn_cast<PHINode>(L)) {
     const PHINode *PNR = cast<PHINode>(R);