[Bug target/105991] [12/13 Regression] rldicl+sldi+add generated instead of rldimi

[roger at nextmovesoftware dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105991

Roger Sayle <roger at nextmovesoftware dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2022-06-16
                 CC|                            |roger at nextmovesoftware dot com
           Keywords|                            |patch
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Roger Sayle <roger at nextmovesoftware dot com> ---
The following patch appears to correct this for me on a cross-compiler to
powerpcle64, but it's tricky for me to do a full bootstrap/regression test.

2022-06-16  Roger Sayle  <roger@nextmovesoftware.com>

gcc/ChangeLog
        PR target/105991
        * config/rs6000/rs6000.md (plus_xor): New code iterator.
        (*rotl<mode>3_insert_3_<code>): New define_insn_and_split.

diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index c55ee7e..695ec33 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -4188,6 +4188,23 @@
 }
   [(set_attr "type" "insert")])

+; Canonicalize the PLUS and XOR forms to IOR for rotl<mode>3_insert_3
+(define_code_iterator plus_xor [plus xor])
+
+(define_insn_and_split "*rotl<mode>3_insert_3_<code>"
+  [(set (match_operand:GPR 0 "gpc_reg_operand" "=r")
+       (plus_xor:GPR
+         (and:GPR (match_operand:GPR 3 "gpc_reg_operand" "0")
+                  (match_operand:GPR 4 "const_int_operand" "n"))
+         (ashift:GPR (match_operand:GPR 1 "gpc_reg_operand" "r")
+                     (match_operand:SI 2 "const_int_operand" "n"))))]
+  "INTVAL (operands[2]) == exact_log2 (UINTVAL (operands[4]) + 1)"
+  "#"
+  "&& 1"
+  [(set (match_dup 0)
+       (ior:GPR (and:GPR (match_dup 3) (match_dup 4))
+                (ashift:GPR (match_dup 1) (match_dup 2))))])
+
 (define_code_iterator plus_ior_xor [plus ior xor])

 (define_split