[PATCH V4 2/3] Using pli for constant splitting

[Jiufu Guo]

Hi,

For constant building e.g. r120=0x66666666, which does not fit 'li or lis',
'pli' is used to build this constant via 'emit_move_insn'.

While for a complicated constant, e.g. 0x6666666666666666ULL, when using
'rs6000_emit_set_long_const' to split the constant recursively, it fails to
use 'pli' to build the half part constant: 0x66666666.

'rs6000_emit_set_long_const' could be updated to use 'pli' to build half
part of the constant when necessary.  For example: 0x6666666666666666ULL,
"pli 3,1717986918; rldimi 3,3,32,0" can be used.

Compare with previous:
https://gcc.gnu.org/pipermail/gcc-patches/2023-December/639492.html
This verion is refreshed and updated testcase name.

Bootstrap&regtest pass on ppc64{,le}.
Is this ok for trunk?

BR,
Jeff (Jiufu Guo)

gcc/ChangeLog:

        * config/rs6000/rs6000.cc (rs6000_emit_set_long_const): Add code to use
        pli for 34bit constant.

gcc/testsuite/ChangeLog:

        * gcc.target/powerpc/const-build-1.c: New test.

---
 gcc/config/rs6000/rs6000.cc                      | 9 ++++++++-
 gcc/testsuite/gcc.target/powerpc/const-build-1.c | 9 +++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.target/powerpc/const-build-1.c

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 017000a4e02..531c40488b4 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -10511,7 +10511,14 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c, 
int *num_insns)
       emit_insn (dest_or_insn);
   };
 
-  if ((ud4 == 0xffff && ud3 == 0xffff && ud2 == 0xffff && (ud1 & 0x8000))
+  if (TARGET_PREFIXED && SIGNED_INTEGER_34BIT_P (c))
+    {
+      /* li/lis/pli */
+      count_or_emit_insn (dest, GEN_INT (c));
+      return;
+    }
+
+ if ((ud4 == 0xffff && ud3 == 0xffff && ud2 == 0xffff && (ud1 & 0x8000))
       || (ud4 == 0 && ud3 == 0 && ud2 == 0 && !(ud1 & 0x8000)))
     {
       /* li */
diff --git a/gcc/testsuite/gcc.target/powerpc/const-build-1.c 
b/gcc/testsuite/gcc.target/powerpc/const-build-1.c
new file mode 100644
index 00000000000..7e35f8c507f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/const-build-1.c
@@ -0,0 +1,9 @@
+/* { dg-do compile { target lp64 } } */
+/* { dg-options "-O2 -mdejagnu-cpu=power10" } */
+/* { dg-require-effective-target power10_ok } */
+
+unsigned long long msk66() { return 0x6666666666666666ULL; }
+
+/* { dg-final { scan-assembler-times {\mpli\M} 1 } } */
+/* { dg-final { scan-assembler-not {\mli\M} } } */
+/* { dg-final { scan-assembler-not {\mlis\M} } } */
-- 
2.25.1