s390: Allow to explicitly omit base register operand in assembly

The base register operand B may be omitted in D(B) by coding D and in
D(L,B) by coding D(L). The index register operand X may be omitted in
D(X,B) by coding D(B) or explicitly omitted by coding D(,B). In both
cases the omitted base register operand value defaults to zero.

Allow to explicitly omit the base register operand B in D(X,B) and
D(L,B) by coding D(X,) and D(L,). Default the omitted base register
operand value to zero.

gas/
	* config/tc-s390.c: Allow to explicitly omit the base register
	operand in assembly.
	* NEWS: Mention that the base register now may be omitted on
	s390.
	* gas/testsuite/gas/s390/zarch-base-index-0.s: Update test cases
	for change to allow to explicitly omit the base register
	operand in assembly.
	* gas/testsuite/gas/s390/zarch-base-index-0.d: Likewise.
	* gas/testsuite/gas/s390/zarch-base-index-0-err.s: Likewise.
	* gas/testsuite/gas/s390/zarch-base-index-0-err.l: Likewise.
	* gas/testsuite/gas/s390/zarch-omitted-base-index.s: Likewise.
	* gas/testsuite/gas/s390/zarch-omitted-base-index.d: Likewise.
	* gas/testsuite/gas/s390/zarch-omitted-base-index-err.s:
	Likewise.
	* gas/testsuite/gas/s390/zarch-omitted-base-index-err.l:
	Likewise.

Reviewed-by: Andreas Krebbel <krebbel@linux.ibm.com>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>

10 files changed, 120 insertions, 165 deletions

diff --git a/gas/NEWS b/gas/NEWS
index 27be28d..5d2a364 100644
--- a/gas/NEWS
+++ b/gas/NEWS
@@ -1,5 +1,9 @@
 -*- text -*-
 
+* The base register operand in D(X,B) and D(L,B) may be explicitly omitted
+  in assembly on s390. It can now be coded as D(X,) or D(L,) instead of D(X,0)
+  D(X,%r0), D(L,0), and D(L,%r0).
+
 * Warn when a register name type does not match the operand type on s390.
   Add support for s390-specific option "warn-regtype-mismatch=[strict|relaxed|
   no]" to override the register name type check behavior. The default
diff --git a/gas/config/tc-s390.c b/gas/config/tc-s390.c
index 9659875..edf8883 100644
--- a/gas/config/tc-s390.c
+++ b/gas/config/tc-s390.c
@@ -1683,13 +1683,17 @@ md_gather_operands (char *str,
       else
 	{
 	  /* We can find an 'early' closing parentheses in e.g. D(L) instead
-	     of D(L,B).  In this case the base register has to be skipped.  */
-	  if (*str == ')')
+	     of D(L,B). In this case the base register has to be skipped.
+	     Same if the base register has been explicilty omitted in e.g.
+	     D(X,) or D(L,).  */
+	  if (*str == ')' || (str[0] == ',' && str[1] == ')'))
 	    {
 	      operand = s390_operands + *(++opindex_ptr);
 
 	      if (!(operand->flags & S390_OPERAND_BASE))
-		as_bad (_("syntax error; ')' not allowed here"));
+		as_bad (_("syntax error; '%c' not allowed here"), *str);
+	      if (*str == ',')
+		str++;
 	      str++;
 	    }
 
diff --git a/gas/testsuite/gas/s390/zarch-base-index-0-err.l b/gas/testsuite/gas/s390/zarch-base-index-0-err.l
index 1762b6e..e7d03ec 100644
--- a/gas/testsuite/gas/s390/zarch-base-index-0-err.l
+++ b/gas/testsuite/gas/s390/zarch-base-index-0-err.l
@@ -5,122 +5,70 @@
 .*:8: Error: syntax error; missing '\)' after base register
 .*:9: Error: bad expression
 .*:9: Error: syntax error; missing '\)' after base register
-.*:10: Error: bad expression
-.*:10: Error: syntax error; missing '\)' after base register
-.*:11: Error: bad expression
-.*:11: Error: syntax error; missing '\)' after base register
 .*:12: Error: bad expression
 .*:12: Error: syntax error; missing '\)' after base register
+.*:13: Error: bad expression
+.*:13: Error: syntax error; missing '\)' after base register
+.*:14: Error: bad expression
+.*:14: Error: syntax error; missing '\)' after base register
 .*:15: Error: bad expression
 .*:15: Error: syntax error; missing '\)' after base register
 .*:16: Error: bad expression
 .*:16: Error: syntax error; missing '\)' after base register
-.*:17: Error: bad expression
-.*:17: Error: syntax error; missing '\)' after base register
-.*:18: Error: bad expression
-.*:18: Error: syntax error; missing '\)' after base register
-.*:19: Error: bad expression
-.*:19: Error: syntax error; missing '\)' after base register
-.*:20: Error: bad expression
-.*:20: Error: syntax error; missing '\)' after base register
+.*:17: Error: operand out of range \(0 is not between 1 and 256\)
+.*:18: Error: missing operand
+.*:19: Error: missing operand
+.*:20: Error: missing operand
 .*:21: Error: bad expression
+.*:21: Error: operand out of range \(0 is not between 1 and 256\)
+.*:21: Error: operand out of range \(32 is not between 0 and 15\)
 .*:21: Error: syntax error; missing '\)' after base register
+.*:21: Error: syntax error; expected ','
 .*:21: Error: bad expression
+.*:21: Error: found 'r', expected: '\)'
 .*:21: Error: syntax error; missing '\)' after base register
-.*:22: Error: bad expression
-.*:22: Error: syntax error; missing '\)' after base register
-.*:23: Error: bad expression
-.*:23: Error: syntax error; missing '\)' after base register
-.*:24: Error: operand out of range \(0 is not between 1 and 256\)
-.*:25: Error: missing operand
-.*:26: Error: missing operand
+.*:21: Error: junk at end of line: `r2\)'
+.*:22: Error: syntax error; missing '\(' after displacement
+.*:23: Error: invalid length field specified
+.*:26: Error: operand out of range \(0 is not between 1 and 16\)
 .*:27: Error: missing operand
-.*:27: Error: bad expression
-.*:27: Error: syntax error; missing '\)' after base register
-.*:28: Error: bad expression
-.*:28: Error: operand out of range \(0 is not between 1 and 256\)
-.*:28: Error: operand out of range \(32 is not between 0 and 15\)
-.*:28: Error: syntax error; missing '\)' after base register
-.*:28: Error: syntax error; expected ','
-.*:28: Error: bad expression
-.*:28: Error: found 'r', expected: '\)'
-.*:28: Error: syntax error; missing '\)' after base register
-.*:28: Error: junk at end of line: `r2\)'
-.*:29: Error: syntax error; missing '\(' after displacement
-.*:30: Error: invalid length field specified
-.*:33: Error: bad expression
-.*:33: Error: syntax error; missing '\)' after base register
-.*:34: Error: bad expression
-.*:34: Error: syntax error; missing '\)' after base register
-.*:35: Error: bad expression
-.*:35: Error: syntax error; missing '\)' after base register
+.*:28: Error: missing operand
+.*:29: Error: missing operand
+.*:30: Error: bad expression
+.*:30: Error: operand out of range \(0 is not between 1 and 16\)
+.*:30: Error: operand out of range \(32 is not between 0 and 15\)
+.*:30: Error: syntax error; missing '\)' after base register
+.*:30: Error: syntax error; expected ','
+.*:30: Error: found ',', expected: '\)'
+.*:31: Error: syntax error; missing '\(' after displacement
+.*:32: Error: operand out of range \(0 is not between 1 and 16\)
+.*:33: Error: missing operand
+.*:34: Error: missing operand
+.*:35: Error: missing operand
 .*:36: Error: bad expression
-.*:36: Error: syntax error; missing '\)' after base register
-.*:37: Error: bad expression
-.*:37: Error: syntax error; missing '\)' after base register
-.*:38: Error: bad expression
-.*:38: Error: syntax error; missing '\)' after base register
-.*:39: Error: bad expression
-.*:39: Error: syntax error; missing '\)' after base register
-.*:39: Error: bad expression
-.*:39: Error: syntax error; missing '\)' after base register
-.*:40: Error: bad expression
-.*:40: Error: syntax error; missing '\)' after base register
-.*:41: Error: bad expression
-.*:41: Error: syntax error; missing '\)' after base register
+.*:36: Error: operand out of range \(0 is not between 1 and 16\)
+.*:36: Error: syntax error; expected ','
+.*:37: Error: syntax error; missing '\(' after displacement
+.*:38: Error: operand out of range \(0 is not between 1 and 16\)
+.*:38: Error: operand out of range \(0 is not between 1 and 16\)
+.*:39: Error: missing operand
+.*:39: Error: missing operand
+.*:40: Error: missing operand
+.*:40: Error: missing operand
+.*:41: Error: missing operand
+.*:41: Error: missing operand
+.*:42: Error: bad expression
 .*:42: Error: operand out of range \(0 is not between 1 and 16\)
-.*:43: Error: missing operand
-.*:44: Error: missing operand
-.*:45: Error: missing operand
-.*:45: Error: bad expression
-.*:45: Error: syntax error; missing '\)' after base register
+.*:42: Error: operand out of range \(32 is not between 0 and 15\)
+.*:42: Error: syntax error; missing '\)' after base register
+.*:42: Error: syntax error; expected ','
+.*:42: Error: bad expression
+.*:42: Error: missing '\)'
+.*:42: Error: operand out of range \(0 is not between 1 and 16\)
+.*:42: Error: syntax error; expected ','
+.*:43: Error: syntax error; missing '\(' after displacement
+.*:43: Error: syntax error; missing '\(' after displacement
 .*:46: Error: bad expression
-.*:46: Error: operand out of range \(0 is not between 1 and 16\)
-.*:46: Error: operand out of range \(32 is not between 0 and 15\)
 .*:46: Error: syntax error; missing '\)' after base register
-.*:46: Error: syntax error; expected ','
-.*:46: Error: found ',', expected: '\)'
-.*:47: Error: syntax error; missing '\(' after displacement
-.*:48: Error: operand out of range \(0 is not between 1 and 16\)
-.*:49: Error: missing operand
-.*:50: Error: missing operand
-.*:51: Error: missing operand
-.*:51: Error: bad expression
-.*:51: Error: syntax error; missing '\)' after base register
-.*:52: Error: bad expression
-.*:52: Error: operand out of range \(0 is not between 1 and 16\)
-.*:52: Error: syntax error; expected ','
-.*:53: Error: syntax error; missing '\(' after displacement
-.*:54: Error: operand out of range \(0 is not between 1 and 16\)
-.*:54: Error: operand out of range \(0 is not between 1 and 16\)
-.*:55: Error: missing operand
-.*:55: Error: missing operand
-.*:56: Error: missing operand
-.*:56: Error: missing operand
-.*:57: Error: missing operand
-.*:57: Error: bad expression
-.*:57: Error: syntax error; missing '\)' after base register
-.*:57: Error: missing operand
-.*:57: Error: bad expression
-.*:57: Error: syntax error; missing '\)' after base register
-.*:58: Error: bad expression
-.*:58: Error: operand out of range \(0 is not between 1 and 16\)
-.*:58: Error: operand out of range \(32 is not between 0 and 15\)
-.*:58: Error: syntax error; missing '\)' after base register
-.*:58: Error: syntax error; expected ','
-.*:58: Error: bad expression
-.*:58: Error: missing '\)'
-.*:58: Error: operand out of range \(0 is not between 1 and 16\)
-.*:58: Error: syntax error; expected ','
-.*:59: Error: syntax error; missing '\(' after displacement
-.*:59: Error: syntax error; missing '\(' after displacement
-.*:62: Error: bad expression
-.*:62: Error: syntax error; missing '\)' after base register
-.*:63: Error: bad expression
-.*:63: Error: syntax error; missing '\)' after base register
-.*:64: Error: bad expression
-.*:64: Error: syntax error; missing '\)' after base register
-.*:65: Error: bad expression
-.*:65: Error: syntax error; missing '\)' after base register
-.*:66: Error: bad expression
-.*:66: Error: syntax error; missing '\)' after base register
+.*:47: Error: bad expression
+.*:47: Error: syntax error; missing '\)' after base register
diff --git a/gas/testsuite/gas/s390/zarch-base-index-0-err.s b/gas/testsuite/gas/s390/zarch-base-index-0-err.s
index 175cc90..472d24e 100644
--- a/gas/testsuite/gas/s390/zarch-base-index-0-err.s
+++ b/gas/testsuite/gas/s390/zarch-base-index-0-err.s
@@ -5,21 +5,14 @@ foo:
 	mvi	16(),32			# syntax error: empty parentheses
 
 #		R1,D2(X2,B2)
-	a	%r1,16(%r2,)		# syntax error: explicitly omitted base
-	a	%r1,16(%r0,)		# syntax error: explicitly omitted base
-	a	%r1,16(0,)		# syntax error: explicitly omitted base
 	a	%r1,16(,)		# syntax error: explicitly omitted index & base
 	a	%r1,16()		# syntax error: empty parentheses
 
 #		D1(L1,B1),D2(B2)
-	mvc	16(1,),32(%r2)		# syntax error: explicitly omitted base
 	mvc	16(1,%r1),32()		# syntax error: empty parentheses
 	mvc	16(1,%r0),32()		# syntax error: empty parentheses
 	mvc	16(1,0),32()		# syntax error: empty parentheses
-	mvc	16(1,),32(%r0)		# syntax error: explicitly omitted base
-	mvc	16(1,),32(0)		# syntax error: explicitly omitted base
 	mvc	16(1,),32()		# syntax error: explicitly omitted base & empty parentheses
-	mvc	16(1,),32		# syntax error: explicitly omitted base
 	mvc	16(1),32()		# syntax error: empty parentheses
 	mvc	16(0,%r1),32(%r2)	# syntax error: length 0
 	mvc	16(,%r1),32(%r2)	# syntax error: explicitly omitted length
@@ -30,15 +23,6 @@ foo:
 	mvc	16(%r1),32(%r2)		# syntax error: omitted length
 
 #		D1(L1,B1),D2(L2,B2)
-	unpk	16(1,),32(2,%r2)	# syntax error: explicitly omitted base
-	unpk	16(1,%r1),32(2,)	# syntax error: explicitly omitted base
-	unpk	16(1,%r0),32(2,)	# syntax error: explicitly omitted base
-	unpk	16(1,0),32(2,)		# syntax error: explicitly omitted base
-	unpk	16(1,),32(2,%r0)	# syntax error: explicitly omitted base
-	unpk	16(1,),32(2,0)		# syntax error: explicitly omitted base
-	unpk	16(1,),32(2,)		# syntax error: explicitly omitted base
-	unpk	16(1,),32(2)		# syntax error: explicitly omitted base
-	unpk	16(1),32(2,)		# syntax error: explicitly omitted base
 	unpk	16(0,%r1),32(2,%r2)	# syntax error: length 0
 	unpk	16(,%r1),32(2,%r2)	# syntax error: explicitly omitted length
 	unpk	16(,1),32(2,%r2)	# syntax error: explicitly omitted length
@@ -59,8 +43,5 @@ foo:
 	unpk	16,32			# syntax error: missing lengths
 
 #		V1,D2(VX2,B2),M3
-	vgef	%v1,16(%v2,),0		# syntax error: explicitly omitted base
-	vgef	%v1,16(%v0,),0		# syntax error: explicitly omitted base
-	vgef	%v1,16(0,),0		# syntax error: explicitly omitted base
 	vgef	%v1,16(,),0		# syntax error: explicitly omitted index & base
 	vgef	%v1,16(),0		# syntax error: empty parentheses
diff --git a/gas/testsuite/gas/s390/zarch-base-index-0.d b/gas/testsuite/gas/s390/zarch-base-index-0.d
index 4dd913b..717eaac 100644
--- a/gas/testsuite/gas/s390/zarch-base-index-0.d
+++ b/gas/testsuite/gas/s390/zarch-base-index-0.d
@@ -19,6 +19,9 @@ Disassembly of section .text:
 .*:	5a 10 30 10 [	 ]*a	%r1,16\(%r3\)
 .*:	5a 12 00 10 [	 ]*a	%r1,16\(%r2,0\)
 .*:	5a 12 00 10 [	 ]*a	%r1,16\(%r2,0\)
+.*:	5a 12 00 10 [	 ]*a	%r1,16\(%r2,0\)
+.*:	5a 10 00 10 [	 ]*a	%r1,16
+.*:	5a 10 00 10 [	 ]*a	%r1,16
 .*:	5a 10 00 10 [	 ]*a	%r1,16
 .*:	5a 10 00 10 [	 ]*a	%r1,16
 .*:	5a 10 00 10 [	 ]*a	%r1,16
@@ -34,6 +37,7 @@ Disassembly of section .text:
 .*:	d2 00 00 10 20 20 [	 ]*mvc	16\(1,0\),32\(%r2\)
 .*:	d2 00 00 10 20 20 [	 ]*mvc	16\(1,0\),32\(%r2\)
 .*:	d2 00 00 10 20 20 [	 ]*mvc	16\(1,0\),32\(%r2\)
+.*:	d2 00 00 10 20 20 [	 ]*mvc	16\(1,0\),32\(%r2\)
 .*:	d2 00 10 10 00 20 [	 ]*mvc	16\(1,%r1\),32
 .*:	d2 00 10 10 00 20 [	 ]*mvc	16\(1,%r1\),32
 .*:	d2 00 10 10 00 20 [	 ]*mvc	16\(1,%r1\),32
@@ -46,14 +50,26 @@ Disassembly of section .text:
 .*:	d2 00 00 10 00 20 [	 ]*mvc	16\(1,0\),32
 .*:	d2 00 00 10 00 20 [	 ]*mvc	16\(1,0\),32
 .*:	d2 00 00 10 00 20 [	 ]*mvc	16\(1,0\),32
+.*:	d2 00 00 10 00 20 [	 ]*mvc	16\(1,0\),32
+.*:	d2 00 00 10 00 20 [	 ]*mvc	16\(1,0\),32
+.*:	d2 00 00 10 00 20 [	 ]*mvc	16\(1,0\),32
 .*:	d2 00 00 00 00 00 [	 ]*mvc	0\(1,0\),0
 .*:	f3 01 10 10 20 20 [	 ]*unpk	16\(1,%r1\),32\(2,%r2\)
 .*:	f3 01 00 10 20 20 [	 ]*unpk	16\(1,0\),32\(2,%r2\)
 .*:	f3 01 00 10 20 20 [	 ]*unpk	16\(1,0\),32\(2,%r2\)
 .*:	f3 01 00 10 20 20 [	 ]*unpk	16\(1,0\),32\(2,%r2\)
+.*:	f3 01 00 10 20 20 [	 ]*unpk	16\(1,0\),32\(2,%r2\)
 .*:	f3 01 10 10 00 20 [	 ]*unpk	16\(1,%r1\),32\(2,0\)
 .*:	f3 01 10 10 00 20 [	 ]*unpk	16\(1,%r1\),32\(2,0\)
 .*:	f3 01 10 10 00 20 [	 ]*unpk	16\(1,%r1\),32\(2,0\)
+.*:	f3 01 10 10 00 20 [	 ]*unpk	16\(1,%r1\),32\(2,0\)
+.*:	f3 01 00 10 00 20 [	 ]*unpk	16\(1,0\),32\(2,0\)
+.*:	f3 01 00 10 00 20 [	 ]*unpk	16\(1,0\),32\(2,0\)
+.*:	f3 01 00 10 00 20 [	 ]*unpk	16\(1,0\),32\(2,0\)
+.*:	f3 01 00 10 00 20 [	 ]*unpk	16\(1,0\),32\(2,0\)
+.*:	f3 01 00 10 00 20 [	 ]*unpk	16\(1,0\),32\(2,0\)
+.*:	f3 01 00 10 00 20 [	 ]*unpk	16\(1,0\),32\(2,0\)
+.*:	f3 01 00 10 00 20 [	 ]*unpk	16\(1,0\),32\(2,0\)
 .*:	f3 01 00 10 00 20 [	 ]*unpk	16\(1,0\),32\(2,0\)
 .*:	f3 01 00 10 00 20 [	 ]*unpk	16\(1,0\),32\(2,0\)
 .*:	f3 01 00 10 00 20 [	 ]*unpk	16\(1,0\),32\(2,0\)
@@ -71,6 +87,9 @@ Disassembly of section .text:
 .*:	e7 10 30 10 00 13 [	 ]*vgef	%v1,16\(%r3\),0
 .*:	e7 12 00 10 00 13 [	 ]*vgef	%v1,16\(%v2,0\),0
 .*:	e7 12 00 10 00 13 [	 ]*vgef	%v1,16\(%v2,0\),0
+.*:	e7 12 00 10 00 13 [	 ]*vgef	%v1,16\(%v2,0\),0
+.*:	e7 10 00 10 00 13 [	 ]*vgef	%v1,16,0
+.*:	e7 10 00 10 00 13 [	 ]*vgef	%v1,16,0
 .*:	e7 10 00 10 00 13 [	 ]*vgef	%v1,16,0
 .*:	e7 10 00 10 00 13 [	 ]*vgef	%v1,16,0
 .*:	e7 10 00 10 00 13 [	 ]*vgef	%v1,16,0
diff --git a/gas/testsuite/gas/s390/zarch-base-index-0.s b/gas/testsuite/gas/s390/zarch-base-index-0.s
index 15c792d..e34c6267 100644
--- a/gas/testsuite/gas/s390/zarch-base-index-0.s
+++ b/gas/testsuite/gas/s390/zarch-base-index-0.s
@@ -18,13 +18,13 @@ foo:
 	a	%r1,16(%r3)
 	a	%r1,16(%r2,%r0)
 	a	%r1,16(%r2,0)
-#	a	%r1,16(%r2,)		# syntax error: explicitly omitted base
+	a	%r1,16(%r2,)		# syntax error: explicitly omitted base
 	a	%r1,16(%r0,%r0)
 	a	%r1,16(%r0,0)
-#	a	%r1,16(%r0,)		# syntax error: explicitly omitted base
+	a	%r1,16(%r0,)		# syntax error: explicitly omitted base
 	a	%r1,16(0,%r0)
 	a	%r1,16(0,0)
-#	a	%r1,16(0,)		# syntax error: explicitly omitted base
+	a	%r1,16(0,)		# syntax error: explicitly omitted base
 	a	%r1,16(0,%r0)
 	a	%r1,16(,%r0)
 	a	%r1,16(,0)
@@ -39,7 +39,7 @@ foo:
 	mvc	16(1,%r1),32(%r2)
 	mvc	16(1,%r0),32(%r2)
 	mvc	16(1,0),32(%r2)
-#	mvc	16(1,),32(%r2)		# syntax error: explicitly omitted base
+	mvc	16(1,),32(%r2)
 	mvc	16(1),32(%r2)
 	mvc	16(1,%r1),32(%r0)
 	mvc	16(1,%r1),32(0)
@@ -53,10 +53,10 @@ foo:
 	mvc	16(1,0),32(0)
 #	mvc	16(1,0),32()		# syntax error: empty parentheses
 	mvc	16(1,0),32
-#	mvc	16(1,),32(%r0)		# syntax error: explicitly omitted base
-#	mvc	16(1,),32(0)		# syntax error: explicitly omitted base
+	mvc	16(1,),32(%r0)
+	mvc	16(1,),32(0)
 #	mvc	16(1,),32()		# syntax error: explicitly omitted base & empty parentheses
-#	mvc	16(1,),32		# syntax error: explicitly omitted base
+	mvc	16(1,),32
 	mvc	16(1),32(%r0)
 	mvc	16(1),32(0)
 #	mvc	16(1),32()		# syntax error: empty parentheses
@@ -67,27 +67,27 @@ foo:
 	unpk	16(1,%r1),32(2,%r2)
 	unpk	16(1,%r0),32(2,%r2)
 	unpk	16(1,0),32(2,%r2)
-#	unpk	16(1,),32(2,%r2)	# syntax error: explicitly omitted base
+	unpk	16(1,),32(2,%r2)
 	unpk	16(1),32(2,%r2)
 	unpk	16(1,%r1),32(2,%r0)
 	unpk	16(1,%r1),32(2,0)
-#	unpk	16(1,%r1),32(2,)	# syntax error: explicitly omitted base
+	unpk	16(1,%r1),32(2,)
 	unpk	16(1,%r1),32(2)
 	unpk	16(1,%r0),32(2,%r0)
 	unpk	16(1,%r0),32(2,0)
-#	unpk	16(1,%r0),32(2,)	# syntax error: explicitly omitted base
+	unpk	16(1,%r0),32(2,)
 	unpk	16(1,%r0),32(2)
 	unpk	16(1,0),32(2,%r0)
 	unpk	16(1,0),32(2,0)
-#	unpk	16(1,0),32(2,)		# syntax error: explicitly omitted base
+	unpk	16(1,0),32(2,)
 	unpk	16(1,0),32(2)
-#	unpk	16(1,),32(2,%r0)	# syntax error: explicitly omitted base
-#	unpk	16(1,),32(2,0)		# syntax error: explicitly omitted base
-#	unpk	16(1,),32(2,)		# syntax error: explicitly omitted base
-#	unpk	16(1,),32(2)		# syntax error: explicitly omitted base
+	unpk	16(1,),32(2,%r0)
+	unpk	16(1,),32(2,0)
+	unpk	16(1,),32(2,)
+	unpk	16(1,),32(2)
 	unpk	16(1),32(2,%r0)
 	unpk	16(1),32(2,0)
-#	unpk	16(1),32(2,)		# syntax error: explicitly omitted base
+	unpk	16(1),32(2,)
 	unpk	16(1),32(2)
 	unpk	0(1),0(2)
 
@@ -99,13 +99,13 @@ foo:
 	vgef	%v1,16(%r3),0
 	vgef	%v1,16(%v2,%r0),0
 	vgef	%v1,16(%v2,0),0
-#	vgef	%v1,16(%v2,),0		# syntax error: explicitly omitted base
+	vgef	%v1,16(%v2,),0
 	vgef	%v1,16(%v0,%r0),0
 	vgef	%v1,16(%v0,0),0
-#	vgef	%v1,16(%v0,),0		# syntax error: explicitly omitted base
+	vgef	%v1,16(%v0,),0
 	vgef	%v1,16(0,%r0),0
 	vgef	%v1,16(0,0),0
-#	vgef	%v1,16(0,),0		# syntax error: explicitly omitted base
+	vgef	%v1,16(0,),0
 	vgef	%v1,16(,%r0),0
 	vgef	%v1,16(,0),0
 #	vgef	%v1,16(,),0		# syntax error: explicitly omitted index & base
diff --git a/gas/testsuite/gas/s390/zarch-omitted-base-index-err.l b/gas/testsuite/gas/s390/zarch-omitted-base-index-err.l
index e4bd7a8..f222fe0 100644
--- a/gas/testsuite/gas/s390/zarch-omitted-base-index-err.l
+++ b/gas/testsuite/gas/s390/zarch-omitted-base-index-err.l
@@ -3,23 +3,19 @@
 .*:5: Error: syntax error; missing '\)' after base register
 .*:8: Error: bad expression
 .*:8: Error: syntax error; missing '\)' after base register
-.*:9: Error: bad expression
-.*:9: Error: syntax error; missing '\)' after base register
+.*:11: Warning: operand 2: expected general register name as base register
 .*:12: Error: bad expression
 .*:12: Error: syntax error; missing '\)' after base register
-.*:13: Warning: operand 2: expected general register name as base register
-.*:14: Error: bad expression
-.*:14: Error: syntax error; missing '\)' after base register
-.*:17: Error: missing operand
-.*:18: Error: missing operand
-.*:19: Error: invalid length field specified
-.*:20: Error: bad expression
-.*:20: Error: operand out of range \(0 is not between 1 and 256\)
-.*:20: Error: operand out of range \(32 is not between 0 and 15\)
-.*:20: Error: syntax error; missing '\)' after base register
-.*:20: Error: syntax error; expected ','
-.*:20: Error: bad expression
-.*:20: Error: found 'r', expected: '\)'
-.*:20: Error: syntax error; missing '\)' after base register
-.*:20: Error: junk at end of line: `r2\)'
-.*:21: Error: syntax error; missing '\(' after displacement
+.*:15: Error: missing operand
+.*:16: Error: missing operand
+.*:17: Error: invalid length field specified
+.*:18: Error: bad expression
+.*:18: Error: operand out of range \(0 is not between 1 and 256\)
+.*:18: Error: operand out of range \(32 is not between 0 and 15\)
+.*:18: Error: syntax error; missing '\)' after base register
+.*:18: Error: syntax error; expected ','
+.*:18: Error: bad expression
+.*:18: Error: found 'r', expected: '\)'
+.*:18: Error: syntax error; missing '\)' after base register
+.*:18: Error: junk at end of line: `r2\)'
+.*:19: Error: syntax error; missing '\(' after displacement
diff --git a/gas/testsuite/gas/s390/zarch-omitted-base-index-err.s b/gas/testsuite/gas/s390/zarch-omitted-base-index-err.s
index dd0e9fe..0114c64 100644
--- a/gas/testsuite/gas/s390/zarch-omitted-base-index-err.s
+++ b/gas/testsuite/gas/s390/zarch-omitted-base-index-err.s
@@ -5,11 +5,9 @@ foo:
 	clm	%r1,0b1000,16()
 
 #		R1,D2(X2,B2)
-	a	%r1,16(%r2,)
 	a	%r1,16()
 
 #		V1,D2(VX2,B2),M3
-	vgef	%v1,16(%v2,),0
 	vgef	%v1,16(%v2),0
 	vgef	%v1,16(),0
 
diff --git a/gas/testsuite/gas/s390/zarch-omitted-base-index.d b/gas/testsuite/gas/s390/zarch-omitted-base-index.d
index cb168a2..2795a9d 100644
--- a/gas/testsuite/gas/s390/zarch-omitted-base-index.d
+++ b/gas/testsuite/gas/s390/zarch-omitted-base-index.d
@@ -9,10 +9,12 @@ Disassembly of section .text:
 .*:	bd 18 20 10 [	 ]*clm	%r1,8,16\(%r2\)
 .*:	bd 18 00 10 [	 ]*clm	%r1,8,16
 .*:	5a 12 30 10 [	 ]*a	%r1,16\(%r2,%r3\)
+.*:	5a 12 00 10 [	 ]*a	%r1,16\(%r2,0\)
 .*:	5a 10 30 10 [	 ]*a	%r1,16\(%r3\)
 .*:	5a 10 30 10 [	 ]*a	%r1,16\(%r3\)
 .*:	5a 10 00 10 [	 ]*a	%r1,16
 .*:	e7 12 30 10 00 13 [	 ]*vgef	%v1,16\(%v2,%r3\),0
+.*:	e7 12 00 10 00 13 [	 ]*vgef	%v1,16\(%v2,0\),0
 .*:	e7 10 30 10 00 13 [	 ]*vgef	%v1,16\(%r3\),0
 .*:	e7 10 30 10 00 13 [	 ]*vgef	%v1,16\(%r3\),0
 .*:	e7 10 00 10 00 13 [	 ]*vgef	%v1,16,0
@@ -20,3 +22,4 @@ Disassembly of section .text:
 .*:	d2 00 10 10 00 20 [	 ]*mvc	16\(1,%r1\),32
 .*:	d2 00 00 10 20 20 [	 ]*mvc	16\(1,0\),32\(%r2\)
 .*:	d2 00 00 10 00 20 [	 ]*mvc	16\(1,0\),32
+.*:	07 07 [	 ]*nopr	%r7
diff --git a/gas/testsuite/gas/s390/zarch-omitted-base-index.s b/gas/testsuite/gas/s390/zarch-omitted-base-index.s
index 8381319..1d4d434 100644
--- a/gas/testsuite/gas/s390/zarch-omitted-base-index.s
+++ b/gas/testsuite/gas/s390/zarch-omitted-base-index.s
@@ -7,12 +7,14 @@ foo:
 
 #		R1,D1(X2,B2)
 	a	%r1,16(%r2,%r3)
+	a	%r1,16(%r2,)
 	a	%r1,16(,%r3)
 	a	%r1,16(%r3)
 	a	%r1,16
 
 #		V1,D2(VX2,B2),M3
 	vgef	%v1,16(%v2,%r3),0
+	vgef	%v1,16(%v2,),0
 	vgef	%v1,16(,%r3),0
 	vgef	%v1,16(%r3),0
 	vgef	%v1,16,0