[gcc(refs/users/meissner/heads/work069)] Update constraint documentation.

[gcc(refs/users/meissner/heads/work069)] Update constraint documentation.

[Michael Meissner]

https://gcc.gnu.org/g:fef0c987b811662b8caba44bb20ce7b3cab18e7c

commit fef0c987b811662b8caba44bb20ce7b3cab18e7c
Author: Michael Meissner <meissner@linux.ibm.com>
Date:   Fri Sep 17 20:36:13 2021 -0400

    Update constraint documentation.
    
    2021-09-17  Michael Meissner  <meissner@linux.ibm.com>
    
    gcc/
    
            * config/rs6000/constraints.md (eQ): Move eQ constraint higher.
            * doc/md.texi (PowerPC and IBM RS6000 constraints): Document the
            eW constraint.

Diff:
---
 gcc/config/rs6000/constraints.md | 10 +++++-----
 gcc/doc/md.texi                  |  3 +++
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/gcc/config/rs6000/constraints.md b/gcc/config/rs6000/constraints.md
index f9d1d1ab446..d960c7e0d5f 100644
--- a/gcc/config/rs6000/constraints.md
+++ b/gcc/config/rs6000/constraints.md
@@ -224,16 +224,16 @@
   "A signed 34-bit integer constant if prefixed instructions are supported."
   (match_operand 0 "cint34_operand"))
 
-;; V2DI/V2DF vector constant that can be loaded with the XXSPLTIDP instruction.
-(define_constraint "eV"
-  "A 128-bit vector constant that can be loaded with the XXSPLTIDP instruction."
-  (match_operand 0 "easy_vector_constant_64bit_element"))
-
 ;; KF/TF scalar than can be loaded with LXVKQ
 (define_constraint "eQ"
   "An IEEE 128-bit constant that can be loaded with the LXVKQ instruction."
   (match_operand 0 "easy_fp_constant_ieee128"))
 
+;; V2DI/V2DF vector constant that can be loaded with the XXSPLTIDP instruction.
+(define_constraint "eV"
+  "A 128-bit vector constant that can be loaded with the XXSPLTIDP instruction."
+  (match_operand 0 "easy_vector_constant_64bit_element"))
+
 ;; Vector constant that can be loaded with XXSPLTIW
 (define_constraint "eW"
   "A vector constant that can be loaded with the XXSPLTIW instruction."
diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
index 892e2866883..feaa205291a 100644
--- a/gcc/doc/md.texi
+++ b/gcc/doc/md.texi
@@ -3348,6 +3348,9 @@ An IEEE 128-bit constant that can be loaded with the LXVKQ instruction.
 @item eV
 A 128-bit vector constant that can be loaded with the XXSPLTIDP instruction.
 
+@item eW
+A vector constant that can be loaded with the XXSPLTIW instruction.
+
 @ifset INTERNALS
 @item G
 A floating point constant that can be loaded into a register with one