x86: PadLock adjustments

For one, all PadLock insns depend on CR4.FXSR to be enabled, which means
they ought to be taking FXSR as a prereq.

Furthermore none of them permits a REPNE prefix; such forms are documented
to cause #UD. (This is mainly relevant for XSTORE, which doesn't include a
REP prefix in its base encoding. For the others this merely is a change in
what diagnostic is issued.)

Finally it is documented that an operand size prefix also causes #UD.

gas/config/tc-i386.c

@@ -4899,11 +4899,6 @@ check_hle (void)
   switch (i.tm.opcode_modifier.prefixok)
     {
     default:
-      abort ();
-    case PrefixLock:
-    case PrefixNone:
-    case PrefixNoTrack:
-    case PrefixRep:
       as_bad (_("invalid instruction `%s' after `%s'"),
 	      insn_name (&i.tm), i.hle_prefix);
       return 0;
@@ -7372,7 +7367,9 @@ i386_assemble (char *line)
       return;
 
   /* Check if REP prefix is OK.  */
-  if (i.rep_prefix && i.tm.opcode_modifier.prefixok != PrefixRep)
+  if (i.rep_prefix && i.tm.opcode_modifier.prefixok != PrefixRep
+      && (i.prefix[REP_PREFIX] != REPE_PREFIX_OPCODE
+	  || i.tm.opcode_modifier.prefixok != PrefixRepe))
     {
       as_bad (_("invalid instruction `%s' after `%s'"),
 		insn_name (&i.tm), i.rep_prefix);
@@ -7416,9 +7413,13 @@ i386_assemble (char *line)
 
   if ((is_any_vex_encoding (&i.tm) && i.tm.opcode_space != SPACE_MAP4)
       || i.tm.operand_types[i.imm_operands].bitfield.class >= RegMMX
-      || i.tm.operand_types[i.imm_operands + 1].bitfield.class >= RegMMX)
+      || i.tm.operand_types[i.imm_operands + 1].bitfield.class >= RegMMX
+      /* (Ab)use the PrefixRepe attribute of PadLock insns as long as no
+	 others use it.  */
+      || i.tm.opcode_modifier.prefixok == PrefixRepe)
     {
-      /* Check for data size prefix on VEX/XOP/EVEX encoded and SIMD insns.  */
+      /* Check for data size prefix on VEX/XOP/EVEX encoded, SIMD, and
+	 PadLock insns.  */
       if (i.prefix[DATA_PREFIX])
 	{
 	  as_bad (_("data size prefix invalid with `%s'"), insn_name (&i.tm));

gas/testsuite/gas/i386/i386.exp

@@ -114,6 +114,7 @@ if [gas_32_check] then {
     run_dump_test "quoted2"
     run_dump_test "unary"
     run_dump_test "padlock"
+    run_list_test "padlock-bad"
     run_dump_test "gmi"
     run_dump_test "padlockrng2"
     run_dump_test "padlockphe2"

gas/testsuite/gas/i386/padlock-bad.l

@@ -0,0 +1,5 @@
+.* Assembler messages:
+.*:8: Error: invalid instruction `xstore' after `repne'
+.*:10: Error: data size prefix invalid with `xstore'
+.*:15: Error: invalid instruction `xsha1' after `repne'
+.*:17: Error: data size prefix invalid with `xsha1'

gas/testsuite/gas/i386/padlock-bad.s

@@ -0,0 +1,17 @@
+# VIA Nehemiah PadLock instructions w/ (problematic) prefixes
+
+	.text
+foo:
+	xstore
+	rep xstore
+	repe xstore
+	repne xstore
+
+	data16 xstore
+
+	xsha1
+	rep xsha1
+	repe xsha1
+	repne xsha1
+
+	data16 xsha1