Now that tblgen can handle matching implicit defs of instructions

Now that tblgen can handle matching implicit defs of instructions
to input patterns, we can fix X86ISD::CMP and X86ISD::BT as taking
two inputs (which have to be the same type) and *returning an i32*.
This is how the SDNodes get made in the graph, but we weren't able
to model it this way due to deficiencies in the pattern language.

Now we can change things like this:

 def UCOM_FpIr80: FpI_<(outs), (ins RFP80:$lhs, RFP80:$rhs), CompareFP,
-                  [(X86cmp RFP80:$lhs, RFP80:$rhs),
-                   (implicit EFLAGS)]>; // CC = ST(0) cmp ST(i)
+                  [(set EFLAGS, (X86cmp RFP80:$lhs, RFP80:$rhs))]>;

and fix terrible crimes like this:

-def : Pat<(parallel (X86cmp GR8:$src1, 0), (implicit EFLAGS)),
+def : Pat<(X86cmp GR8:$src1, 0),
           (TEST8rr GR8:$src1, GR8:$src1)>;

This relies on matching the result of TEST8rr (which is EFLAGS, which is
an implicit def) to the result of X86cmp, an i32.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98903 91177308-0d34-0410-b5e6-96231b3b80d8