Enable PostRA scheduling for SPU. 
This speeds up selected test cases with up to
5% - no slowdowns observed.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120286 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/CellSPU/SPUSubtarget.cpp b/lib/Target/CellSPU/SPUSubtarget.cpp
index 0f18b7f..07c8352 100644
--- a/lib/Target/CellSPU/SPUSubtarget.cpp
+++ b/lib/Target/CellSPU/SPUSubtarget.cpp
@@ -14,6 +14,8 @@
 #include "SPUSubtarget.h"
 #include "SPU.h"
 #include "SPUGenSubtarget.inc"
+#include "llvm/ADT/SmallVector.h"
+#include "SPURegisterInfo.h"
 
 using namespace llvm;
 
@@ -34,3 +36,22 @@
 /// producing code for the JIT.
 void SPUSubtarget::SetJITMode() {
 }
+
+/// Enable PostRA scheduling for optimization levels -O2 and -O3.
+bool SPUSubtarget::enablePostRAScheduler(
+                       CodeGenOpt::Level OptLevel,
+                       TargetSubtarget::AntiDepBreakMode& Mode,
+                       RegClassVector& CriticalPathRCs) const {
+  Mode = TargetSubtarget::ANTIDEP_CRITICAL;
+  // CriticalPathsRCs seems to be the set of
+  // RegisterClasses that antidep breakings are performed for.
+  // Do it for all register classes 
+  CriticalPathRCs.clear();
+  CriticalPathRCs.push_back(&SPU::R8CRegClass);
+  CriticalPathRCs.push_back(&SPU::R16CRegClass);
+  CriticalPathRCs.push_back(&SPU::R32CRegClass);
+  CriticalPathRCs.push_back(&SPU::R32FPRegClass);
+  CriticalPathRCs.push_back(&SPU::R64CRegClass);
+  CriticalPathRCs.push_back(&SPU::VECREGRegClass);
+  return OptLevel >= CodeGenOpt::Default;
+}