CodeGen: Move check of EnablePostRAScheduler to avoid disabling antid…

…ependency breaker

Previously, specifying -post-RA-scheduler=true had the side effect of
disabling the antidependency breaker, yielding different behavior than
if the post-RA-scheduler was enabled via the scheduling model.

Differential Revision: http://reviews.llvm.org/D20186

llvm-svn: 270077

llvm/lib/CodeGen/PostRASchedulerList.cpp

@@ -103,6 +103,7 @@ namespace {
 
     bool runOnMachineFunction(MachineFunction &Fn) override;
 
+  private:
     bool enablePostRAScheduler(
         const TargetSubtargetInfo &ST, CodeGenOpt::Level OptLevel,
         TargetSubtargetInfo::AntiDepBreakMode &Mode,
@@ -269,6 +270,11 @@ bool PostRAScheduler::enablePostRAScheduler(
     TargetSubtargetInfo::RegClassVector &CriticalPathRCs) const {
   Mode = ST.getAntiDepBreakMode();
   ST.getCriticalPathRCs(CriticalPathRCs);
+
+  // Check for explicit enable/disable of post-ra scheduling.
+  if (EnablePostRAScheduler.getPosition() > 0)
+    return EnablePostRAScheduler;
+
   return ST.enablePostRAScheduler() &&
          OptLevel >= ST.getOptLevelToEnablePostRAScheduler();
 }
@@ -284,20 +290,15 @@ bool PostRAScheduler::runOnMachineFunction(MachineFunction &Fn) {
 
   RegClassInfo.runOnMachineFunction(Fn);
 
-  // Check for explicit enable/disable of post-ra scheduling.
   TargetSubtargetInfo::AntiDepBreakMode AntiDepMode =
     TargetSubtargetInfo::ANTIDEP_NONE;
   SmallVector<const TargetRegisterClass*, 4> CriticalPathRCs;
-  if (EnablePostRAScheduler.getPosition() > 0) {
-    if (!EnablePostRAScheduler)
-      return false;
-  } else {
-    // Check that post-RA scheduling is enabled for this target.
-    // This may upgrade the AntiDepMode.
-    if (!enablePostRAScheduler(Fn.getSubtarget(), PassConfig->getOptLevel(),
-                               AntiDepMode, CriticalPathRCs))
-      return false;
-  }
+
+  // Check that post-RA scheduling is enabled for this target.
+  // This may upgrade the AntiDepMode.
+  if (!enablePostRAScheduler(Fn.getSubtarget(), PassConfig->getOptLevel(),
+                             AntiDepMode, CriticalPathRCs))
+    return false;
 
   // Check for antidep breaking override...
   if (EnableAntiDepBreaking.getPosition() > 0) {