From 135c9821e8806defa455a47208fb897fff1a3ff8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Tue, 23 Jun 2015 08:53:50 +0200
Subject: Make the 'r' operand type optional

The 'r' type is now mandatory. That means in order to handle
both of the following instructions:

  move x(0) y(7)
  move x(1) y(7)

we would need to define two specific operations in ops.tab:

  move r y
  move x y

We want to make 'r' operands optional. That is, if we have
only this specific instruction:

  move x y

it will match both of the following instructions:

  move x(0) y(7)
  move x(1) y(7)

Make 'r' optional allows us to save code space when we don't
want to make handling of x(0) a special case, but we can still
use 'r' to optimize commonly used instructions.
---
 erts/emulator/utils/beam_makeops | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

(limited to 'erts/emulator/utils')

diff --git a/erts/emulator/utils/beam_makeops b/erts/emulator/utils/beam_makeops
index 00b0df5b73..e61096355c 100755
--- a/erts/emulator/utils/beam_makeops
+++ b/erts/emulator/utils/beam_makeops
@@ -176,7 +176,7 @@ sub define_type_bit {
     }
 
     # Composed types.
-    define_type_bit('d', $type_bit{'x'} | $type_bit{'y'} | $type_bit{'r'});
+    define_type_bit('d', $type_bit{'x'} | $type_bit{'y'});
     define_type_bit('c', $type_bit{'i'} | $type_bit{'a'} |
 		    $type_bit{'n'} | $type_bit{'q'});
     define_type_bit('s', $type_bit{'d'} | $type_bit{'i'} |
@@ -528,12 +528,16 @@ sub emulator_output {
 
 	    my(@bits) = (0) x ($max_spec_operands/2);
 	    my($i);
+	    my $involves_r = 0;
 	    for ($i = 0; $i < $max_spec_operands && defined $args[$i]; $i++) {
 		my $t = $args[$i];
-		if (defined $type_bit{$t}) {
-		    my $shift = $max_genop_types * ($i % 2);
-		    $bits[int($i/2)] |= $type_bit{$t} << $shift;
+		my $bits = $type_bit{$t};
+		if ($t eq 'r') {
+		    $bits |= $type_bit{'x'};
+		    $involves_r |= 1 << $i;
 		}
+		my $shift = $max_genop_types * ($i % 2);
+		$bits[int($i/2)] |= $bits << $shift;
 	    }
 
 	    printf "/* %3d */  ", $spec_opnum;
@@ -545,7 +549,7 @@ sub emulator_output {
 		$sep = ",";
 	    }
 	    $init .= "}";
-	    &init_item($print_name, $init, $size, $pack, $sign, 0);
+	    init_item($print_name, $init, $involves_r, $size, $pack, $sign, 0);
 	    $op_to_name[$spec_opnum] = $instr;
 	    $spec_opnum++;
 	}
@@ -1310,6 +1314,8 @@ sub tr_parse_op {
 	foreach (split('', $type)) {
 	    &error("bad type in $op")
 		unless defined $type_bit{$_} or $type eq '*';
+	    $_ eq 'r' and
+		error("$op: 'r' is not allowed in transformations")
 	}
     }
 
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