[AArch64] Tweak operand choice for SVE predicate AND

[AArch64] Tweak operand choice for SVE predicate AND

SVE defines an assembly alias:

   MOV pa.B, pb/Z, pc.B  ->  AND pa.B. pb/Z, pc.B, pc.B

Our and<mode>3 pattern was instead using the functionally-equivalent:

   AND pa.B. pb/Z, pb.B, pc.B
                   ^^^^
This patch duplicates pc.B instead so that the alias can be seen
in disassembly.

I wondered about using the alias in the pattern instead, but using AND
explicitly seems to fit better with the pattern name and surrounding code.

2019-08-15  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* config/aarch64/aarch64-sve.md (and<PRED_ALL:mode>3): Make the
	operand order match the MOV /Z alias.

From-SVN: r274521