aarch64 disassembler infinite loop

[Alan Modra]

Assembling this to an object and trying to disassemble results in
objdump -d looping forever.

 .inst 0x45205120

	PR 25270
	* aarch64-dis.c (aarch64_decode_variant_using_iclass): Return
	false when field is zero for sve_size_tsz_bhs.

diff --git a/opcodes/aarch64-dis.c b/opcodes/aarch64-dis.c
index 9300569813..8b32097a5f 100644
--- a/opcodes/aarch64-dis.c
+++ b/opcodes/aarch64-dis.c
@@ -2843,6 +2843,8 @@ aarch64_decode_variant_using_iclass (aarch64_inst *inst)
 
     case sve_size_tsz_bhs:
       i = extract_fields (inst->value, 0, 2, FLD_SVE_sz, FLD_SVE_tszl_19);
+      if (i == 0)
+	return FALSE;
       while (i != 1)
 	{
 	  if (i & 1)

-- 
Alan Modra
Australia Development Lab, IBM