[1/2] rs6000: use lis;xoris to build constant

Message ID 20221201084754.12959-1-guojiufu@linux.ibm.com
State New
Headers
Series [1/2] rs6000: use lis;xoris to build constant |

Commit Message

Jiufu Guo Dec. 1, 2022, 8:47 a.m. UTC
  Hi,

For constant C:
If '(c & 0xFFFFFFFF0000FFFFULL) == 0xFFFFFFFF00000000' or say:
32(1) || 1(0) || 15(x) || 16(0), we could use "lis; xoris" to build.

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.
Bootstrap and regtest pass on ppc64{,le}.

Is this ok for trunk?

BR,
Jeff (Jiufu)


	PR target/106708

gcc/ChangeLog:

	* config/rs6000/rs6000.cc (rs6000_emit_set_long_const): Add to build
	constants through "lis; xoris".

gcc/testsuite/ChangeLog:

	* gcc.target/powerpc/pr106708.c: New test.

---
 gcc/config/rs6000/rs6000.cc                 |  7 +++++++
 gcc/testsuite/gcc.target/powerpc/pr106708.c | 23 +++++++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708.c
  

Patch

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 1a51b79ebfe..7efed94a0bc 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -10251,6 +10251,13 @@  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 && !(ud2 & 0x8000) && ud1 == 0)
+    {
+      /* lis; xoris */
+      temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
+      emit_move_insn (temp, GEN_INT (sext_hwi ((ud2 | 0x8000) << 16, 32)));
+      emit_move_insn (dest, gen_rtx_XOR (DImode, temp, GEN_INT (0x80000000)));
+    }
   else if (ud3 == 0 && ud4 == 0)
     {
       temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
diff --git a/gcc/testsuite/gcc.target/powerpc/pr106708.c b/gcc/testsuite/gcc.target/powerpc/pr106708.c
new file mode 100644
index 00000000000..dd0386c109c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr106708.c
@@ -0,0 +1,23 @@ 
+/* PR target/106708 */
+/* { dg-do run } */
+/* { dg-options "-O2 -mno-prefixed -save-temps" } */
+/* { dg-require-effective-target has_arch_ppc64 } */
+
+long long arr[] = {0xffffffff65430000LL};
+void __attribute__ ((__noipa__)) lisxoris (long long *arg)
+{
+  *arg = 0xffffffff65430000LL;
+}
+/* { dg-final { scan-assembler-times {\mlis .*,0xe543\M} 1 } } */
+/* { dg-final { scan-assembler-times {\mxoris .*0x8000\M} 1 } } */
+
+int
+main ()
+{
+  long long a[sizeof (arr) / sizeof (arr[0])];
+
+  lisxoris (a);
+  if (__builtin_memcmp (a, arr, sizeof (arr)) != 0)
+    __builtin_abort ();
+  return 0;
+}