[gcc r12-2042] Remove redundant compare in shift loop on H8

[gcc r12-2042] Remove redundant compare in shift loop on H8

[Jeff Law]

https://gcc.gnu.org/g:1562c7987be115311a75b1074c3768a1b006adb6

commit r12-2042-g1562c7987be115311a75b1074c3768a1b006adb6
Author: Jeff Law <jeffreyalaw@gmail.com>
Date:   Mon Jul 5 17:23:43 2021 -0400

    Remove redundant compare in shift loop on H8
    
    gcc/ChangeLog
    
            * config/h8300/shiftrotate.md (shift-by-variable patterns): Update to
            generate condition code aware RTL directly.

Diff:
---
 gcc/config/h8300/shiftrotate.md | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/gcc/config/h8300/shiftrotate.md b/gcc/config/h8300/shiftrotate.md
index 0476324bf22..485303cb906 100644
--- a/gcc/config/h8300/shiftrotate.md
+++ b/gcc/config/h8300/shiftrotate.md
@@ -385,10 +385,15 @@
    (parallel
      [(set (match_dup 0)
 	   (match_op_dup 2 [(match_dup 0) (const_int 1)]))
-      (clobber (scratch:QI))])
-   (set (match_dup 1) (plus:QI (match_dup 1) (const_int -1)))
+      (clobber (reg:CC CC_REG))])
+   (parallel
+     [(set (reg:CCZN CC_REG)
+	   (compare:CCZN
+	     (plus:QI (match_dup 1) (const_int -1))
+	     (const_int 0)))
+      (set (match_dup 1) (plus:QI (match_dup 1) (const_int -1)))])
    (set (pc)
-        (if_then_else (ne (match_dup 1) (const_int 0))
+        (if_then_else (ne (reg:CCZN CC_REG) (const_int 0))
 		      (label_ref (match_dup 4))
 		      (pc)))
    (match_dup 5)]
@@ -416,10 +421,15 @@
    (parallel
      [(set (match_dup 0)
 	   (match_op_dup 2 [(match_dup 0) (const_int 1)]))
-      (clobber (scratch:QI))])
-   (set (match_dup 3) (plus:QI (match_dup 3) (const_int -1)))
+      (clobber (reg:CC CC_REG))])
+   (parallel
+     [(set (reg:CCZN CC_REG)
+	   (compare:CCZN
+	     (plus:QI (match_dup 3) (const_int -1))
+	     (const_int 0)))
+      (set (match_dup 3) (plus:QI (match_dup 3) (const_int -1)))])
    (set (pc)
-        (if_then_else (ne (match_dup 3) (const_int 0))
+        (if_then_else (ne (reg:CCZN CC_REG) (const_int 0))
 		      (label_ref (match_dup 4))
 		      (pc)))
    (match_dup 5)]