gas: adjust handling of quotes for .irpc

The present handling of inner double quotes can lead to very strange
diagnostics. Follow one of the two possible interpretations of the doc:
@dots{} referring to possibly multiple white space separated
@var{values}, each of which may be quoted. The original implementation,
prior to 465e561723 ("PR gas/3856"), hints at the other possible
interpretation: When quoted there's only a single @var{values}, with
inner quotes taken as ordinary characters. That, however, seems overall
less useful to me.

While touching the documentation, mirror the (inverse) spelling
correction (@section line inconsistent with actual description) to .irp
as well.

gas/doc/as.texi

@@ -5859,7 +5859,7 @@ processing must also be performed upon the  symbols as well.
 @end ifset
 
 @node Irp
-@section @code{.irp @var{symbol},@var{values}}@dots{}
+@section @code{.irp @var{symbol},@var{value}}@dots{}
 
 @cindex @code{irp} directive
 Evaluate a sequence of statements assigning different values to @var{symbol}.
@@ -5893,12 +5893,13 @@ For some caveats with the spelling of @var{symbol}, see also @ref{Macro}.
 
 @cindex @code{irpc} directive
 Evaluate a sequence of statements assigning different values to @var{symbol}.
-The sequence of statements starts at the @code{.irpc} directive, and is
-terminated by an @code{.endr} directive.  For each character in @var{value},
-@var{symbol} is set to the character, and the sequence of statements is
-assembled.  If no @var{value} is listed, the sequence of statements is
-assembled once, with @var{symbol} set to the null string.  To refer to
-@var{symbol} within the sequence of statements, use @var{\symbol}.
+The sequence of statements starts at the line following the @code{.irpc}
+directive, and is terminated by an @code{.endr} directive.  For each character
+in each (possibly double quoted) @var{values}, @var{symbol} is set to the
+character, and the sequence of statements is assembled.  If no @var{values} is
+listed, the sequence of statements is assembled once, with @var{symbol} set to
+the null string.  To refer to @var{symbol} within the sequence of statements,
+use @var{\symbol}.
 
 For example, assembling
 

gas/macro.c

@@ -1369,12 +1369,6 @@ expand_irp (int irpc, size_t idx, sb *in, sb *out, size_t (*get_line) (sb *))
     {
       bool in_quotes = false;
 
-      if (irpc && in->ptr[idx] == '"')
-	{
-	  in_quotes = true;
-	  ++idx;
-	}
-
       while (idx < in->len)
 	{
 	  if (!irpc)
@@ -1383,16 +1377,14 @@ expand_irp (int irpc, size_t idx, sb *in, sb *out, size_t (*get_line) (sb *))
 	    {
 	      if (in->ptr[idx] == '"')
 		{
-		  size_t nxt;
+		  in_quotes = ! in_quotes;
+		  ++idx;
 
-		  if (irpc)
-		    in_quotes = ! in_quotes;
-
-		  nxt = sb_skip_white (idx + 1, in);
-		  if (nxt >= in->len)
+		  if (! in_quotes)
 		    {
-		      idx = nxt;
-		      break;
+		      idx = sb_skip_white (idx, in);
+		      if (idx >= in->len)
+			break;
 		    }
 		}
 	      sb_reset (&f.actual);

gas/testsuite/gas/macros/irpc-quote.l

@@ -0,0 +1,18 @@
+# This should match the output of gas irpc-quote.s.
+#...
+> <
+>a<
+>b<
+>c<
+>d<
+> <
+>e<
+>f<
+>1<
+>2<
+> <
+>3<
+>4<
+>5<
+>6<
+> <

gas/testsuite/gas/macros/irpc-quote.s

@@ -0,0 +1,6 @@
+	.irpc c, " ab" cd " ef"
+	.print ">\c<"
+	.endr
+	.irpc c, "12 " 34 "56 "
+	.print ">\c<"
+	.endr

gas/testsuite/gas/macros/macros.exp

@@ -109,3 +109,5 @@ run_list_test count
 # AIX targets need an extended regexp to match "\+".
 setup_xfail "avr-*-*" "cris*-*-*" "msp430-*-*" "z80-*-*" "*-*-aix*"
 run_list_test irp-count
+
+run_list_test irpc-quote