Allow ARM if-converter to be run after post allocation scheduling.

- This fixed a number of bugs in if-converter, tail merging, and post-allocation
  scheduler. If-converter now runs branch folding / tail merging first to
  maximize if-conversion opportunities.
- Also changed the t2IT instruction slightly. It now defines the ITSTATE
  register which is read by instructions in the IT block.
- Added Thumb2 specific hazard recognizer to ensure the scheduler doesn't
  change the instruction ordering in the IT block (since IT mask has been
  finalized). It also ensures no other instructions can be scheduled between
  instructions in the IT block.

This is not yet enabled.

llvm-svn: 106344

1 files changed, 10 insertions, 2 deletions

diff --git a/llvm/lib/Target/ARM/ARMMachineFunctionInfo.h b/llvm/lib/Target/ARM/ARMMachineFunctionInfo.h
index 01342763559..7e57a1ca557 100644
--- a/llvm/lib/Target/ARM/ARMMachineFunctionInfo.h
+++ b/llvm/lib/Target/ARM/ARMMachineFunctionInfo.h
@@ -88,6 +88,9 @@ class ARMFunctionInfo : public MachineFunctionInfo {
   /// VarArgsFrameIndex - FrameIndex for start of varargs area.
   int VarArgsFrameIndex;
 
+  /// HasITBlocks - True if IT blocks have been inserted.
+  bool HasITBlocks;
+
 public:
   ARMFunctionInfo() :
     isThumb(false),
@@ -97,7 +100,8 @@ public:
     FramePtrSpillOffset(0), GPRCS1Offset(0), GPRCS2Offset(0), DPRCSOffset(0),
     GPRCS1Size(0), GPRCS2Size(0), DPRCSSize(0),
     GPRCS1Frames(0), GPRCS2Frames(0), DPRCSFrames(0),
-    JumpTableUId(0), ConstPoolEntryUId(0), VarArgsFrameIndex(0) {}
+    JumpTableUId(0), ConstPoolEntryUId(0), VarArgsFrameIndex(0),
+    HasITBlocks(false) {}
 
   explicit ARMFunctionInfo(MachineFunction &MF) :
     isThumb(MF.getTarget().getSubtarget<ARMSubtarget>().isThumb()),
@@ -108,7 +112,8 @@ public:
     GPRCS1Size(0), GPRCS2Size(0), DPRCSSize(0),
     GPRCS1Frames(32), GPRCS2Frames(32), DPRCSFrames(32),
     SpilledCSRegs(MF.getTarget().getRegisterInfo()->getNumRegs()),
-    JumpTableUId(0), ConstPoolEntryUId(0), VarArgsFrameIndex(0) {}
+    JumpTableUId(0), ConstPoolEntryUId(0), VarArgsFrameIndex(0),
+    HasITBlocks(false) {}
 
   bool isThumbFunction() const { return isThumb; }
   bool isThumb1OnlyFunction() const { return isThumb && !hasThumb2; }
@@ -229,6 +234,9 @@ public:
 
   int getVarArgsFrameIndex() const { return VarArgsFrameIndex; }
   void setVarArgsFrameIndex(int Index) { VarArgsFrameIndex = Index; }
+
+  bool hasITBlocks() const { return HasITBlocks; }
+  void setHasITBlocks(bool h) { HasITBlocks = h; }
 };
 } // End llvm namespace