metag build error

[Alan Modra]

gas/config/tc-metag.c: In function ‘parse_dsp_addr’:
gas/config/tc-metag.c:4386:29: error: ‘regs[0]’ may be used uninitialized [-Werror=maybe-uninitialized]
 4386 |   if (!is_addr_unit (regs[0]->unit) &&
      |                      ~~~~~~~^~~~~~

It looks like regs_read can be zero with "l" non-NULL, so this gcc
complaint is accurate.

	* config/tc-metag.c (parse_dsp_addr, parse_dget_set): Check
	regs_read.

diff --git a/gas/config/tc-metag.c b/gas/config/tc-metag.c
index 09ee5c3acea..cd0c50ff9c9 100644
--- a/gas/config/tc-metag.c
+++ b/gas/config/tc-metag.c
@@ -4380,11 +4380,10 @@ parse_dsp_addr (const char *line, metag_addr *addr, unsigned int size,
 
   l = parse_dsp_regs_list (l, regs, 1, &regs_read, true, true, load, false);
 
-  if (l == NULL)
+  if (l == NULL || regs_read == 0)
     return NULL;
 
-  if (!is_addr_unit (regs[0]->unit) &&
-      !is_dspram_reg (regs[0]))
+  if (!is_addr_unit (regs[0]->unit) && !is_dspram_reg (regs[0]))
     {
       as_bad (_("invalid register for memory access"));
       return NULL;
@@ -4434,7 +4433,7 @@ parse_dsp_addr (const char *line, metag_addr *addr, unsigned int size,
 
   l = parse_dsp_regs_list (l, regs, 1, &regs_read, true, true, load, false);
 
-  if (l == NULL)
+  if (l == NULL || regs_read == 0)
     return NULL;
 
   if (regs[0]->unit != addr->base_reg->unit)
@@ -4522,7 +4521,7 @@ parse_dget_set (const char *line, metag_insn *insn,
 			       false, false);
     }
 
-  if (l == NULL)
+  if (l == NULL || regs_read == 0)
     return NULL;
 
   /* The first register dictates the unit.  */

-- 
Alan Modra