Bug 1282795 - Make a variable DebugOnly, and extract a side effect on that variable from an assertion expression to avoid a clang compiler warning when a side-effectful expression appears in unevaluated context. r=froydnj

--HG--
extra : rebase_source : c45b2b2fff55457383b8da86b9b597a5fb60b587

js/src/jit/IonAnalysis.cpp

@@ -2866,9 +2866,10 @@ jit::AssertExtendedGraphCoherency(MIRGraph& graph, bool underValueNumberer)
 
     AssertDominatorTree(graph);
 
-    uint32_t idx = 0;
+    DebugOnly<uint32_t> idx = 0;
     for (MBasicBlockIterator block(graph.begin()); block != graph.end(); block++) {
-        MOZ_ASSERT(block->id() == idx++);
+        MOZ_ASSERT(block->id() == idx);
+        ++idx;
 
         // No critical edges:
         if (block->numSuccessors() > 1)