[PowerPC][NFC] Reclaim TSFlags bit 6

[jsji]

Summary

We removed UseVSXReg flag in https://reviews.llvm.org/D58685
But we did not reclain the bit 6 it was assigned,
this will become confusing and a hole later..
We should reclaim it as early as possible before new bits.

[merge_guards_bot]

Unit tests: pass. 61794 tests passed, 0 failed and 781 were skipped.

clang-tidy: unknown.

clang-format: pass.

Build artifacts: diff.json, clang-format.patch, CMakeCache.txt, console-log.txt, test-results.xml

[nemanjai]

This introduces a dependency for https://reviews.llvm.org/D72569.

[jsji]

In D72649#1818217, @nemanjai wrote:

This introduces a dependency for https://reviews.llvm.org/D72569.

Yes, this is actually found while reviewing https://reviews.llvm.org/D72569,
Depends on which one go in first, the other one should rebase..

[jsji]

Ping...

[sfertile]

LGTM.

llvm/lib/Target/PowerPC/PPCInstrFormats.td

class I<bits<6> opcode, dag OOL, dag IOL, string asmstr, InstrItinClass itin>
   /// these must be reflected there!  See comments there for what these are.
   let TSFlags{0}   = PPC970_First;
   let TSFlags{1}   = PPC970_Single;
   let TSFlags{2}   = PPC970_Cracked;
   let TSFlags{5-3} = PPC970_Unit;
 
   // Indicate that this instruction is of type X-Form Load or Store
   bits<1> XFormMemOp = 0;
-  let TSFlags{7}  = XFormMemOp;
+  let TSFlags{6}  = XFormMemOp;
 
   // Fields used for relation models.
   string BaseName = "";
 
   // For cases where multiple instruction definitions really represent the
   // same underlying instruction but with one definition for 64-bit arguments
   // and one for 32-bit arguments, this bit breaks the degeneracy between
   // the two forms and allows TableGen to generate mapping tables.

llvm/lib/Target/PowerPC/PPCInstrInfo.h

enum PPC970_Unit {
   PPC970_BRU    = 7 << PPC970_Shift    // Branch Unit
 };
 
 enum {
   /// Shift count to bypass PPC970 flags
   NewDef_Shift = 6,
 
   /// This instruction is an X-Form memory operation.
-  XFormMemOp = 0x1 << (NewDef_Shift+1)
+  XFormMemOp = 0x1 << NewDef_Shift
 };
 } // end namespace PPCII
 
 // Instructions that have an immediate form might be convertible to that
 // form if the correct input is a result of a load immediate. In order to
 // know whether the transformation is special, we might need to know some
 // of the details of the two forms.
 struct ImmInstrInfo {