On Sun, Dec 22, 2019 at 11:49:19AM -0600, Segher Boessenkool wrote:
> On Fri, Dec 20, 2019 at 06:49:30PM -0500, Michael Meissner wrote:
> > In doing V11 patch #3, I noticed that the documentation for the 'Q' was
> > misleading.
>
> It originally was used just for lswi/stswi, which can access up to the
> first 32 bytes of storage pointed to by the register. But yes, the
> current comment is confusing.
>
> > * config/rs6000/constraints.md (Q constraint): Update
> > documentation.
> > * doc/md.tet (PowerPC constraints): Update 'Q' constraint
> > documentation.
>
> "md.tet"? That's an interesting typo :-)
>
> > (define_memory_constraint "Q"
> > - "Memory operand that is an offset from a register (it is usually better
> > -to use @samp{m} or @samp{es} in @code{asm} statements)"
> > + "A memory operand whose address which uses a single register with no
> > offset."
>
> Arm has
>
> (define_memory_constraint "Q"
> "@internal
> An address that is a single base register."
> (and (match_code "mem")
> (match_test "REG_P (XEXP (op, 0))")))
>
> which is more correct for us (the register cannot be r0!)
>
> But it is not an address.
>
> Maybe "A memory operand addressed by just a base register." ?
>
> Okay for trunk like that. Thanks!
This is the patch I committed (subversion ids 279939 and 279940).
2020-01-06 Michael Meissner <meiss...@linux.ibm.com>
* config/rs6000/constraints.md (Q constraint): Update
documentation.
* doc/md.texi (RS/6000 constraints): Update 'Q' cosntraint
documentation.
Index: gcc/config/rs6000/constraints.md
===================================================================
--- gcc/config/rs6000/constraints.md (revision 279910)
+++ gcc/config/rs6000/constraints.md (working copy)
@@ -211,8 +211,7 @@ several times, or that might not access
(match_test "GET_RTX_CLASS (GET_CODE (XEXP (op, 0))) != RTX_AUTOINC")))
(define_memory_constraint "Q"
- "Memory operand that is an offset from a register (it is usually better
-to use @samp{m} or @samp{es} in @code{asm} statements)"
+ "A memory operand addressed by just a base register."
(and (match_code "mem")
(match_test "REG_P (XEXP (op, 0))")))
Index: gcc/doc/md.texi
===================================================================
--- gcc/doc/md.texi (revision 279910)
+++ gcc/doc/md.texi (working copy)
@@ -3381,8 +3381,7 @@ allowed when @samp{<} or @samp{>} is use
as @samp{m} without @samp{<} and @samp{>}.
@item Q
-Memory operand that is an offset from a register (it is usually better
-to use @samp{m} or @samp{es} in @code{asm} statements)
+A memory operand addressed by just a base register.
@item Z
Memory operand that is an indexed or indirect from a register (it is
--
Michael Meissner, IBM
IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA
email: meiss...@linux.ibm.com, phone: +1 (978) 899-4797
