[gcc r13-4771] rs6000: use li;x?oris to build constant

[gcc r13-4771] rs6000: use li;x?oris to build constant

[Jiu Fu Guo]

https://gcc.gnu.org/g:97a8e88cd7d22562c0ea4f73687d3c93c21e12fb

commit r13-4771-g97a8e88cd7d22562c0ea4f73687d3c93c21e12fb
Author: Jiufu Guo <guojiufu@linux.ibm.com>
Date:   Mon Dec 19 16:40:01 2022 +0800

    rs6000: use li;x?oris to build constant
    
    For constant C:
    If '(c & 0xFFFFFFFF00008000ULL) == 0xFFFFFFFF00008000ULL' or say:
    32(1) || 16(x) || 1(1) || 15(x), using "li; xoris" would be ok.
    
    If '(c & 0xFFFFFFFF80008000ULL) == 0x80000000ULL' or say:
    32(0) || 1(1) || 15(x) || 1(0) || 15(x), we could use "li; oris" to
    build constant 'C'.
    
    Here N(M) means N continuous bit M, x for M means it is ok for either
    1 or 0; '||' means concatenation.
    
    This patch update rs6000_emit_set_long_const to support those constants.
    
            PR target/106708
    
    gcc/ChangeLog:
    
            * config/rs6000/rs6000.cc (rs6000_emit_set_long_const): Add using
            "li; x?oris" to build constant.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/powerpc/pr106708.c: New test.

Diff:
---
 gcc/config/rs6000/rs6000.cc                 | 37 +++++++++++++++++++++-----
 gcc/testsuite/gcc.target/powerpc/pr106708.c | 41 +++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+), 6 deletions(-)

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index b3a609f3aa3..9318ef151c9 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -10251,17 +10251,42 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
       if (ud1 != 0)
 	emit_move_insn (dest, gen_rtx_IOR (DImode, temp, GEN_INT (ud1)));
     }
+  else if (ud4 == 0xffff && ud3 == 0xffff && (ud1 & 0x8000))
+    {
+      /* li; xoris */
+      temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
+      emit_move_insn (temp, GEN_INT (sext_hwi (ud1, 16)));
+      emit_move_insn (dest, gen_rtx_XOR (DImode, temp,
+					 GEN_INT ((ud2 ^ 0xffff) << 16)));
+    }
   else if (ud3 == 0 && ud4 == 0)
     {
       temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
 
       gcc_assert (ud2 & 0x8000);
-      emit_move_insn (temp, GEN_INT (sext_hwi (ud2 << 16, 32)));
-      if (ud1 != 0)
-	emit_move_insn (temp, gen_rtx_IOR (DImode, temp, GEN_INT (ud1)));
-      emit_move_insn (dest,
-		      gen_rtx_ZERO_EXTEND (DImode,
-					   gen_lowpart (SImode,temp)));
+
+      if (ud1 == 0)
+	{
+	  /* lis; rldicl */
+	  emit_move_insn (temp, GEN_INT (sext_hwi (ud2 << 16, 32)));
+	  emit_move_insn (dest,
+			  gen_rtx_AND (DImode, temp, GEN_INT (0xffffffff)));
+	}
+      else if (!(ud1 & 0x8000))
+	{
+	  /* li; oris */
+	  emit_move_insn (temp, GEN_INT (ud1));
+	  emit_move_insn (dest,
+			  gen_rtx_IOR (DImode, temp, GEN_INT (ud2 << 16)));
+	}
+      else
+	{
+	  /* lis; ori; rldicl */
+	  emit_move_insn (temp, GEN_INT (sext_hwi (ud2 << 16, 32)));
+	  emit_move_insn (temp, gen_rtx_IOR (DImode, temp, GEN_INT (ud1)));
+	  emit_move_insn (dest,
+			  gen_rtx_AND (DImode, temp, GEN_INT (0xffffffff)));
+	}
     }
   else if (ud1 == ud3 && ud2 == ud4)
     {
diff --git a/gcc/testsuite/gcc.target/powerpc/pr106708.c b/gcc/testsuite/gcc.target/powerpc/pr106708.c
new file mode 100644
index 00000000000..ddb9160d4b8
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr106708.c
@@ -0,0 +1,41 @@
+/* PR target/106708 */
+/* { dg-do run } */
+/* { dg-options "-O2 -mno-prefixed -save-temps" } */
+/* { dg-require-effective-target has_arch_ppc64 } */
+
+long long arr[]
+  = {0xffffffff7cdeab55LL, 0x98765432LL, 0xabcd0000LL};
+
+void __attribute__ ((__noipa__)) test_li_xoris (long long *arg)
+{
+  *arg = 0xffffffff7cdeab55LL;
+}
+/* { dg-final { scan-assembler-times {\mli .*,-21675\M} 1 } } */
+/* { dg-final { scan-assembler-times {\mxoris .*0x8321\M} 1 } } */
+
+void __attribute__ ((__noipa__)) test_li_oris (long long *arg)
+{
+  *arg = 0x98765432LL;
+}
+/* { dg-final { scan-assembler-times {\mli .*,21554\M} 1 } } */
+/* { dg-final { scan-assembler-times {\moris .*0x9876\M} 1 } } */
+
+void __attribute__ ((__noipa__)) test_lis_rldicl (long long *arg)
+{
+  *arg = 0xabcd0000LL;
+}
+/* { dg-final { scan-assembler-times {\mlis .*,0xabcd\M} 1 } } */
+/* { dg-final { scan-assembler-times {\mrldicl .*,0,32\M} 1 } } */
+
+int
+main ()
+{
+  long long a[sizeof (arr) / sizeof (arr[0])];
+
+  test_li_xoris (a);
+  test_li_oris (a + 1);
+  test_lis_rldicl (a + 2);
+  if (__builtin_memcmp (a, arr, sizeof (arr)) != 0)
+    __builtin_abort ();
+  return 0;
+}