[PATCH] rs6000: avoid ineffective replacement of splitters

[Jiufu Guo via Gcc-patches]

Hi,

As a comment in
https://gcc.gnu.org/pipermail/gcc-patches/2022-August/599556.html

Those splitters call rs6000_emit_set_const directly, and the replacements
are never used.  Using (pc) would be less misleading.

This patch pass bootstrap&regtest on ppc64 BE and LE.
Is this ok for trunk.

BR,
Jeff(Jiufu)

gcc/ChangeLog:

        * config/rs6000/rs6000.md: (constant splitters): Use "(pc)" as the
        replacements.

---
 gcc/config/rs6000/rs6000.md | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index 1367a2cb779..7fadbeef1aa 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -7727,11 +7727,7 @@ (define_split
   [(set (match_operand:SI 0 "gpc_reg_operand")
        (match_operand:SI 1 "const_int_operand"))]
   "num_insns_constant (operands[1], SImode) > 1"
-  [(set (match_dup 0)
-       (match_dup 2))
-   (set (match_dup 0)
-       (ior:SI (match_dup 0)
-               (match_dup 3)))]
+  [(pc)]
 {
   if (rs6000_emit_set_const (operands[0], operands[1]))
     DONE;
@@ -9662,8 +9658,7 @@ (define_split
   [(set (match_operand:DI 0 "int_reg_operand_not_pseudo")
        (match_operand:DI 1 "const_int_operand"))]
   "TARGET_POWERPC64 && num_insns_constant (operands[1], DImode) > 1"
-  [(set (match_dup 0) (match_dup 2))
-   (set (match_dup 0) (plus:DI (match_dup 0) (match_dup 3)))]
+  [(pc)]
 {
   if (rs6000_emit_set_const (operands[0], operands[1]))
     DONE;
@@ -9675,8 +9670,7 @@ (define_split
   [(set (match_operand:DI 0 "int_reg_operand_not_pseudo")
        (match_operand:DI 1 "const_scalar_int_operand"))]
   "TARGET_POWERPC64 && num_insns_constant (operands[1], DImode) > 1"
-  [(set (match_dup 0) (match_dup 2))
-   (set (match_dup 0) (plus:DI (match_dup 0) (match_dup 3)))]
+  [(pc)]
 {
   if (rs6000_emit_set_const (operands[0], operands[1]))
     DONE;
-- 
2.17.1