[PATCH] [AArch64] Enhance rematerialization by adding a new API isAsCheapAsAMove in TargetInstroInfo

[Eric Christopher]

Few inline comments.

================
Comment at: lib/Target/AArch64/AArch64InstrInfo.cpp:544
@@ -543,1 +543,3 @@
 
+// FIXME: this implementation should be u-arch dependent, so a u-arch target
+// hook should be introduced here in future.
----------------
Since this is ascii, just use the word "micro-architecture" :)

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Comment at: lib/Target/AArch64/AArch64InstrInfo.cpp:553
@@ +552,3 @@
+
+  if (TM->getTargetCPU() == "cortex-a57" ||
+      TM->getTargetCPU() == "cortex-a53") {
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This should query the subtarget, not the target machine.

http://reviews.llvm.org/D4361