[PATCH] Enable the instruction printer in HexagonMCTargetDesc

[Sid Manning]

================
Comment at: lib/Target/Hexagon/InstPrinter/HexagonInstPrinter.cpp:56-57
@@ +55,4 @@
+    return ~(-1U << (bits - 1));
+  else
+    return ~(-1U << bits);
+}
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shankarke wrote:
> same as above comment.
OK, will remove both.

================
Comment at: lib/Target/Hexagon/InstPrinter/HexagonInstPrinter.cpp:159
@@ +158,3 @@
+
+  assert((isExtendable(MII.TSFlags) || isExtended(MII.TSFlags)) &&
+         "Expecting an extendable operand");
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rafael wrote:
> Are this changes intended? The description doesn't mention them.
While troublesome, the assert is intended to keep this routine from being attached to an incorrect insn.

The code below is the fix for the actual dependency.  isConstExtended is in LLVMHexagonDesc, when the inst printer is registered in that library a circular dependency is formed.

http://reviews.llvm.org/D5734