--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -236,6 +236,8 @@ enum i386_error
     unsupported_with_intel_mnemonic,
     unsupported_syntax,
     unsupported,
+    unsupported_on_arch,
+    unsupported_64bit,
     invalid_sib_address,
     invalid_vsib_address,
     invalid_vector_register_set,
@@ -4849,6 +4851,15 @@ md_assemble (char *line)
     {
       if (pass1_mnem != NULL)
 	goto match_error;
+      if (i.error != no_error)
+	{
+	  gas_assert (current_templates != NULL);
+	  if (current_templates->start->opcode_modifier.pass2 && !i.suffix)
+	    goto no_match;
+	  /* No point in trying a 2nd pass - it'll only find the same suffix
+	     again.  */
+	  goto match_error;
+	}
       return;
     }
   if (current_templates->start->opcode_modifier.pass2)
@@ -4948,12 +4959,21 @@ md_assemble (char *line)
 	{
 	  line = copy;
 	  copy = NULL;
+  no_match:
 	  pass1_err = i.error;
 	  pass1_mnem = current_templates->start->name;
 	  goto retry;
 	}
-      free (copy);
+
+      /* If a non-/only-64bit template (group) was found in pass 1, and if
+	 _some_ template (group) was found in pass 2, squash pass 1's
+	 error.  */
+      if (pass1_err == unsupported_64bit)
+	pass1_mnem = NULL;
+
   match_error:
+      free (copy);
+
       switch (pass1_mnem ? pass1_err : i.error)
 	{
 	default:
@@ -4986,6 +5006,17 @@ md_assemble (char *line)
 	  as_bad (_("unsupported instruction `%s'"),
 		  pass1_mnem ? pass1_mnem : current_templates->start->name);
 	  return;
+	case unsupported_on_arch:
+	  as_bad (_("`%s' is not supported on `%s%s'"),
+		  pass1_mnem ? pass1_mnem : current_templates->start->name,
+		  cpu_arch_name ? cpu_arch_name : default_arch,
+		  cpu_sub_arch_name ? cpu_sub_arch_name : "");
+	  return;
+	case unsupported_64bit:
+	  as_bad (_("`%s' is %s supported in 64-bit mode"),
+		  pass1_mnem ? pass1_mnem : current_templates->start->name,
+		  flag_code == CODE_64BIT ? _("not") : _("only"));
+	  return;
 	case invalid_sib_address:
 	  err_msg = _("invalid SIB address");
 	  break;
@@ -5601,16 +5632,13 @@ parse_insn (const char *line, char *mnem
 	return l;
     }
 
-  if (!(supported & CPU_FLAGS_64BIT_MATCH))
-    as_bad (flag_code == CODE_64BIT
-	    ? _("`%s' is not supported in 64-bit mode")
-	    : _("`%s' is only supported in 64-bit mode"),
-	    current_templates->start->name);
-  else
-    as_bad (_("`%s' is not supported on `%s%s'"),
-	    current_templates->start->name,
-	    cpu_arch_name ? cpu_arch_name : default_arch,
-	    cpu_sub_arch_name ? cpu_sub_arch_name : "");
+  if (pass1)
+    {
+      if (supported & CPU_FLAGS_64BIT_MATCH)
+        i.error = unsupported_on_arch;
+      else
+        i.error = unsupported_64bit;
+    }
 
   return NULL;
 }
--- a/gas/testsuite/gas/i386/movs.s
+++ b/gas/testsuite/gas/i386/movs.s
@@ -30,4 +30,10 @@ movs:
 .ifdef x86_64
 	movswq	%ax,%rax
 	movswq	(%rax),%rax
+
+	movsl	%eax,%rax
+	movsl	(%rax),%rax
+
+	movslq	%eax,%rax
+	movslq	(%rax),%rax
 .endif
--- a/gas/testsuite/gas/i386/movx64.l
+++ b/gas/testsuite/gas/i386/movx64.l
@@ -241,6 +241,46 @@
 [ 	]*[1-9][0-9]*[ 	]+movswq	%eax, %rcx
 [ 	]*[1-9][0-9]*[ 	]+movswq	%rax, %rcx
 [ 	]*[1-9][0-9]*[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+movsl	%al, %cl
+[ 	]*[1-9][0-9]*[ 	]+movsl	%ax, %cl
+[ 	]*[1-9][0-9]*[ 	]+movsl	%eax, %cl
+[ 	]*[1-9][0-9]*[ 	]+movsl	%rax, %cl
+[ 	]*[1-9][0-9]*[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+movsl	%al, %cx
+[ 	]*[1-9][0-9]*[ 	]+movsl	%ax, %cx
+[ 	]*[1-9][0-9]*[ 	]+movsl	%eax, %cx
+[ 	]*[1-9][0-9]*[ 	]+movsl	%rax, %cx
+[ 	]*[1-9][0-9]*[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+movsl	%al, %ecx
+[ 	]*[1-9][0-9]*[ 	]+movsl	%ax, %ecx
+[ 	]*[1-9][0-9]*[ 	]+movsl	%eax, %ecx
+[ 	]*[1-9][0-9]*[ 	]+movsl	%rax, %ecx
+[ 	]*[1-9][0-9]*[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+movsl	%al, %rcx
+[ 	]*[1-9][0-9]*[ 	]+movsl	%ax, %rcx
+[ 	]*[1-9][0-9]* \?\?\?\? 4863C8[ 	]+movsl	%eax, %rcx
+[ 	]*[1-9][0-9]*[ 	]+movsl	%rax, %rcx
+[ 	]*[1-9][0-9]*[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+movslq	%al, %cl
+[ 	]*[1-9][0-9]*[ 	]+movslq	%ax, %cl
+[ 	]*[1-9][0-9]*[ 	]+movslq	%eax, %cl
+[ 	]*[1-9][0-9]*[ 	]+movslq	%rax, %cl
+[ 	]*[1-9][0-9]*[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+movslq	%al, %cx
+[ 	]*[1-9][0-9]*[ 	]+movslq	%ax, %cx
+[ 	]*[1-9][0-9]*[ 	]+movslq	%eax, %cx
+[ 	]*[1-9][0-9]*[ 	]+movslq	%rax, %cx
+[ 	]*[1-9][0-9]*[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+movslq	%al, %ecx
+[ 	]*[1-9][0-9]*[ 	]+movslq	%ax, %ecx
+[ 	]*[1-9][0-9]*[ 	]+movslq	%eax, %ecx
+[ 	]*[1-9][0-9]*[ 	]+movslq	%rax, %ecx
+[ 	]*[1-9][0-9]*[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+movslq	%al, %rcx
+[ 	]*[1-9][0-9]*[ 	]+movslq	%ax, %rcx
+[ 	]*[1-9][0-9]* \?\?\?\? 4863C8[ 	]+movslq	%eax, %rcx
+[ 	]*[1-9][0-9]*[ 	]+movslq	%rax, %rcx
+[ 	]*[1-9][0-9]*[ 	]*
 [ 	]*[1-9][0-9]*[ 	]+movzx:
 [ 	]*[1-9][0-9]*[ 	]+movzx	%al, %cl
 [ 	]*[1-9][0-9]*[ 	]+movzx	%ax, %cl
--- a/gas/testsuite/gas/i386/movx64.s
+++ b/gas/testsuite/gas/i386/movx64.s
@@ -241,6 +241,46 @@ movsx:
 	movswq	%eax, %rcx
 	movswq	%rax, %rcx
 
+	movsl	%al, %cl
+	movsl	%ax, %cl
+	movsl	%eax, %cl
+	movsl	%rax, %cl
+
+	movsl	%al, %cx
+	movsl	%ax, %cx
+	movsl	%eax, %cx
+	movsl	%rax, %cx
+
+	movsl	%al, %ecx
+	movsl	%ax, %ecx
+	movsl	%eax, %ecx
+	movsl	%rax, %ecx
+
+	movsl	%al, %rcx
+	movsl	%ax, %rcx
+	movsl	%eax, %rcx
+	movsl	%rax, %rcx
+
+	movslq	%al, %cl
+	movslq	%ax, %cl
+	movslq	%eax, %cl
+	movslq	%rax, %cl
+
+	movslq	%al, %cx
+	movslq	%ax, %cx
+	movslq	%eax, %cx
+	movslq	%rax, %cx
+
+	movslq	%al, %ecx
+	movslq	%ax, %ecx
+	movslq	%eax, %ecx
+	movslq	%rax, %ecx
+
+	movslq	%al, %rcx
+	movslq	%ax, %rcx
+	movslq	%eax, %rcx
+	movslq	%rax, %rcx
+
 movzx:
 	movzx	%al, %cl
 	movzx	%ax, %cl
--- a/opcodes/i386-opc.tbl
+++ b/opcodes/i386-opc.tbl
@@ -164,9 +164,7 @@ movbe, 0x0f38f0, None, CpuMovbe, D|Modrm
 // Move with sign extend.
 movsb, 0xfbe, None, Cpu386, Modrm|No_bSuf|No_sSuf|No_ldSuf|Pass2, { Reg8|Unspecified|BaseIndex, Reg16|Reg32|Reg64 }
 movsw, 0xfbf, None, Cpu386, Modrm|No_bSuf|No_wSuf|No_sSuf|No_ldSuf|Pass2, { Reg16|Unspecified|BaseIndex, Reg32|Reg64 }
-// "movslq" must not be converted into "movsl" to avoid conflict with the
-// "movsl" string move instruction.
-movslq, 0x63, None, Cpu64, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|Size64, { Reg32|Dword|Unspecified|BaseIndex, Reg64 }
+movsl, 0x63, None, Cpu64, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_ldSuf|Pass2, { Reg32|Unspecified|BaseIndex, Reg64 }
 movsx, 0xfbe, None, Cpu386, W|Modrm|No_lSuf|No_sSuf|No_qSuf|No_ldSuf, { Reg8|Reg16|Unspecified|BaseIndex, Reg16|Reg32|Reg64 }
 movsx, 0x63, None, Cpu64, Modrm|No_bSuf|No_wSuf|No_sSuf|No_qSuf|No_ldSuf, { Reg32|Unspecified|BaseIndex, Reg32|Reg64 }
 movsxd, 0x63, None, Cpu64, Modrm|No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf, { Reg32|Unspecified|BaseIndex, Reg32|Reg64 }
