Subzero. Changes the Register Allocator so that it is aware of register

src/IceRegAlloc.h

Index: src/IceRegAlloc.h
diff --git a/src/IceRegAlloc.h b/src/IceRegAlloc.h
index f68109171dd9878648e35e4120bb520eda48ffe5..627b82c3406c89b2b11da533a5f22fc6b5bd75e3 100644
--- a/src/IceRegAlloc.h
+++ b/src/IceRegAlloc.h
@@ -108,6 +108,8 @@ private:
   /// currently assigned to. It can be greater than 1 as a result of
   /// AllowOverlap inference.
   llvm::SmallVector<int32_t, REGS_SIZE> RegUses;
+  llvm::SmallVector<const llvm::SmallBitVector *, REGS_SIZE> RegAliases;

[jvoung (off chromium), 2015/09/04 16:14:46]

Just a note that on ARM (and probably MIPS?) the target will have more registers
than will fit in the SmallBitVector's uintptr_t X field (up to 64
single-precision FP slots + 16 GPR slots).

[John, 2015/09/04 17:32:25]

I added a TODO here. Maybe it is worth investigating what the performance
penalty is.

+  TargetLowering *Target;
   bool FindPreference = false;
   bool FindOverlap = false;