[llvm] r266514 - Do not modify a cl::opt programmatically, global mutable state is evil.

[Mehdi Amini via llvm-commits]

Author: mehdi_amini
Date: Fri Apr 15 23:58:30 2016
New Revision: 266514

URL: http://llvm.org/viewvc/llvm-project?rev=266514&view=rev
Log:
Do not modify a cl::opt programmatically, global mutable state is evil.

Found by TSAN on ThinLTO.

From: Mehdi Amini <mehdi.amini at apple.com>

Modified:
    llvm/trunk/lib/CodeGen/ScheduleDAGInstrs.cpp

Modified: llvm/trunk/lib/CodeGen/ScheduleDAGInstrs.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/ScheduleDAGInstrs.cpp?rev=266514&r1=266513&r2=266514&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/ScheduleDAGInstrs.cpp (original)
+++ llvm/trunk/lib/CodeGen/ScheduleDAGInstrs.cpp Fri Apr 15 23:58:30 2016
@@ -62,9 +62,18 @@ static cl::opt<unsigned> HugeRegion("dag
                              "prior to scheduling, at which point a trade-off "
                              "is made to avoid excessive compile time."));
 
-static cl::opt<unsigned> ReductionSize("dag-maps-reduction-size", cl::Hidden,
+static cl::opt<unsigned> ReductionSize(
+    "dag-maps-reduction-size", cl::Hidden,
     cl::desc("A huge scheduling region will have maps reduced by this many "
-	     "nodes at a time. Defaults to HugeRegion / 2."));
+             "nodes at a time. Defaults to HugeRegion / 2."));
+
+static unsigned getReductionSize() {
+  // Always reduce a huge region with half of the elements, except
+  // when user sets this number explicitly.
+  if (ReductionSize.getNumOccurrences() == 0)
+    return HugeRegion / 2;
+  return ReductionSize;
+}
 
 static void dumpSUList(ScheduleDAGInstrs::SUList &L) {
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
@@ -878,11 +887,6 @@ void ScheduleDAGInstrs::buildSchedGraph(
   // done.
   Value2SUsMap NonAliasStores, NonAliasLoads(1 /*TrueMemOrderLatency*/);
 
-  // Always reduce a huge region with half of the elements, except
-  // when user sets this number explicitly.
-  if (ReductionSize.getNumOccurrences() == 0)
-    ReductionSize = (HugeRegion / 2);
-
   // Remove any stale debug info; sometimes BuildSchedGraph is called again
   // without emitting the info from the previous call.
   DbgValues.clear();
@@ -1077,11 +1081,11 @@ void ScheduleDAGInstrs::buildSchedGraph(
     // Reduce maps if they grow huge.
     if (Stores.size() + Loads.size() >= HugeRegion) {
       DEBUG(dbgs() << "Reducing Stores and Loads maps.\n";);
-      reduceHugeMemNodeMaps(Stores, Loads, ReductionSize);
+      reduceHugeMemNodeMaps(Stores, Loads, getReductionSize());
     }
     if (NonAliasStores.size() + NonAliasLoads.size() >= HugeRegion) {
       DEBUG(dbgs() << "Reducing NonAliasStores and NonAliasLoads maps.\n";);
-      reduceHugeMemNodeMaps(NonAliasStores, NonAliasLoads, ReductionSize);
+      reduceHugeMemNodeMaps(NonAliasStores, NonAliasLoads, getReductionSize());
     }
   }