x86: re-arrange process_operands()

Alter the sequence of conditions evaluated, without affecting the
overall result. This is going to help subsequent changes (and as a nice
side effect also slightly reduces overall indentation depth).

While doing this take the liberty of simplifying the calculation of the
operand index of the register operand in ShortForm handling.

2 files changed, 54 insertions, 57 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index fc99adc..185469f 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,8 @@
+2019-11-04  Jan Beulich  <jbeulich@suse.com>
+
+	* config/tc-i386.c (process_operands): Handle ShortForm insns
+	later, splitting out their segment register sub-form.
+
 2019-10-31  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* testsuite/gas/i386/general.s: Add .code16gcc fldenv tests.
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index f26b17c..5866bd6 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -7004,63 +7004,7 @@ duplicate:
       i.reg_operands++;
     }
 
-  if (i.tm.opcode_modifier.shortform)
-    {
-      if (i.types[0].bitfield.sreg)
-	{
-	  if (flag_code != CODE_64BIT
-	      ? i.tm.base_opcode == POP_SEG_SHORT
-		&& i.op[0].regs->reg_num == 1
-	      : (i.tm.base_opcode | 1) == POP_SEG386_SHORT
-		&& i.op[0].regs->reg_num < 4)
-	    {
-	      as_bad (_("you can't `%s %s%s'"),
-		      i.tm.name, register_prefix, i.op[0].regs->reg_name);
-	      return 0;
-	    }
-	  if ( i.op[0].regs->reg_num > 3 && i.tm.opcode_length == 1 )
-	    {
-	      i.tm.base_opcode ^= POP_SEG_SHORT ^ POP_SEG386_SHORT;
-	      i.tm.opcode_length = 2;
-	    }
-	  i.tm.base_opcode |= (i.op[0].regs->reg_num << 3);
-	}
-      else
-	{
-	  /* The register or float register operand is in operand
-	     0 or 1.  */
-	  unsigned int op;
-
-	  if ((i.types[0].bitfield.reg && i.types[0].bitfield.tbyte)
-	      || operand_type_check (i.types[0], reg))
-	    op = 0;
-	  else
-	    op = 1;
-	  /* Register goes in low 3 bits of opcode.  */
-	  i.tm.base_opcode |= i.op[op].regs->reg_num;
-	  if ((i.op[op].regs->reg_flags & RegRex) != 0)
-	    i.rex |= REX_B;
-	  if (!quiet_warnings && i.tm.opcode_modifier.ugh)
-	    {
-	      /* Warn about some common errors, but press on regardless.
-		 The first case can be generated by gcc (<= 2.8.1).  */
-	      if (i.operands == 2)
-		{
-		  /* Reversed arguments on faddp, fsubp, etc.  */
-		  as_warn (_("translating to `%s %s%s,%s%s'"), i.tm.name,
-			   register_prefix, i.op[!intel_syntax].regs->reg_name,
-			   register_prefix, i.op[intel_syntax].regs->reg_name);
-		}
-	      else
-		{
-		  /* Extraneous `l' suffix on fp insn.  */
-		  as_warn (_("translating to `%s %s%s'"), i.tm.name,
-			   register_prefix, i.op[0].regs->reg_name);
-		}
-	    }
-	}
-    }
-  else if (i.tm.opcode_modifier.modrm)
+  if (i.tm.opcode_modifier.modrm)
     {
       /* The opcode is completed (modulo i.tm.extension_opcode which
 	 must be put into the modrm byte).  Now, we make the modrm and
@@ -7068,6 +7012,25 @@ duplicate:
 
       default_seg = build_modrm_byte ();
     }
+  else if (i.types[0].bitfield.sreg)
+    {
+      if (flag_code != CODE_64BIT
+	  ? i.tm.base_opcode == POP_SEG_SHORT
+	    && i.op[0].regs->reg_num == 1
+	  : (i.tm.base_opcode | 1) == POP_SEG386_SHORT
+	    && i.op[0].regs->reg_num < 4)
+	{
+	  as_bad (_("you can't `%s %s%s'"),
+		  i.tm.name, register_prefix, i.op[0].regs->reg_name);
+	  return 0;
+	}
+      if ( i.op[0].regs->reg_num > 3 && i.tm.opcode_length == 1 )
+	{
+	  i.tm.base_opcode ^= POP_SEG_SHORT ^ POP_SEG386_SHORT;
+	  i.tm.opcode_length = 2;
+	}
+      i.tm.base_opcode |= (i.op[0].regs->reg_num << 3);
+    }
   else if ((i.tm.base_opcode & ~0x3) == MOV_AX_DISP32)
     {
       default_seg = &ds;
@@ -7078,6 +7041,35 @@ duplicate:
 	 on one of their operands, the default segment is ds.  */
       default_seg = &ds;
     }
+  else if (i.tm.opcode_modifier.shortform)
+    {
+      /* The register or float register operand is in operand
+	 0 or 1.  */
+      unsigned int op = !i.tm.operand_types[0].bitfield.reg;
+
+      /* Register goes in low 3 bits of opcode.  */
+      i.tm.base_opcode |= i.op[op].regs->reg_num;
+      if ((i.op[op].regs->reg_flags & RegRex) != 0)
+	i.rex |= REX_B;
+      if (!quiet_warnings && i.tm.opcode_modifier.ugh)
+	{
+	  /* Warn about some common errors, but press on regardless.
+	     The first case can be generated by gcc (<= 2.8.1).  */
+	  if (i.operands == 2)
+	    {
+	      /* Reversed arguments on faddp, fsubp, etc.  */
+	      as_warn (_("translating to `%s %s%s,%s%s'"), i.tm.name,
+		       register_prefix, i.op[!intel_syntax].regs->reg_name,
+		       register_prefix, i.op[intel_syntax].regs->reg_name);
+	    }
+	  else
+	    {
+	      /* Extraneous `l' suffix on fp insn.  */
+	      as_warn (_("translating to `%s %s%s'"), i.tm.name,
+		       register_prefix, i.op[0].regs->reg_name);
+	    }
+	}
+    }
 
   if (i.tm.base_opcode == 0x8d /* lea */
       && i.seg[0]