x86/Intel: don't swap operands of MONITOR{,X} and MWAIT{,X}

Generally, the documentation doesn't allow for any explicit operands
to be specified with MONITOR/MWAIT. To permit the more legible
overriding of the address size via specifying operands, the option is
being retained even in Intel mode, but operand swapping is being
suppressed by this patch. This is both because it makes no sense here
(all of the operands are inputs) and because, as a result, old gcc
(prior to 4.8) actually expects it this way with -mintel-syntax (and
hence gets fixed by this change rather than, as claimed by a reply in
the bug report, broken).

1 files changed, 6 insertions, 4 deletions

diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index acade9d..4074a90 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -4324,14 +4324,16 @@ md_assemble (char *line)
   /* Now we've parsed the mnemonic into a set of templates, and have the
      operands at hand.  */
 
-  /* All intel opcodes have reversed operands except for "bound" and
-     "enter".  We also don't reverse intersegment "jmp" and "call"
-     instructions with 2 immediate operands so that the immediate segment
-     precedes the offset, as it does when in AT&T mode. */
+  /* All Intel opcodes have reversed operands except for "bound", "enter"
+     "monitor*", and "mwait*".  We also don't reverse intersegment "jmp"
+     and "call" instructions with 2 immediate operands so that the immediate
+     segment precedes the offset, as it does when in AT&T mode. */
   if (intel_syntax
       && i.operands > 1
       && (strcmp (mnemonic, "bound") != 0)
       && (strcmp (mnemonic, "invlpga") != 0)
+      && (strncmp (mnemonic, "monitor", 7) != 0)
+      && (strncmp (mnemonic, "mwait", 5) != 0)
       && !(operand_type_check (i.types[0], imm)
 	   && operand_type_check (i.types[1], imm)))
     swap_operands ();