@@ -10238,6 +10238,45 @@ rs6000_emit_set_const (rtx dest, rtx source)
return true;
}
+/* Check if C can be rotated to a possitive value which 'li' instruction
+ is able to load. If so, set *ROT to the number by which C is rotated,
+ and return true. Return false otherwise. */
+static bool
+can_be_rotated_to_possitive_li (HOST_WIDE_INT c, int *rot)
+{
+ /* 49 leading zeros and 15 lowbits on the possitive value
+ generated by 'li' instruction. */
+ return can_be_rotated_to_lowbits (c, 15, rot);
+}
+
+/* Like can_be_rotated_to_possitive_li, but check negative value of 'li'. */
+static bool
+can_be_rotated_to_negative_li (HOST_WIDE_INT c, int *rot)
+{
+ return can_be_rotated_to_lowbits (~c, 15, rot);
+}
+
+/* Check if value C can be built by 2 instructions: one is 'li', another is
+ rotldi.
+
+ If so, *SHIFT is set to the shift operand of rotldi(rldicl), and *MASK
+ is set to -1, and return true. Return false otherwise. */
+static bool
+can_be_built_by_li_and_rotldi (HOST_WIDE_INT c, int *shift,
+ HOST_WIDE_INT *mask)
+{
+ int n;
+ if (can_be_rotated_to_possitive_li (c, &n)
+ || can_be_rotated_to_negative_li (c, &n))
+ {
+ *mask = HOST_WIDE_INT_M1;
+ *shift = HOST_BITS_PER_WIDE_INT - n;
+ return true;
+ }
+
+ return false;
+}
+
/* Subroutine of rs6000_emit_set_const, handling PowerPC64 DImode.
Output insns to set DEST equal to the constant C as a series of
lis, ori and shl instructions. */
@@ -10246,15 +10285,14 @@ static void
rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
{
rtx temp;
+ int shift;
+ HOST_WIDE_INT mask;
HOST_WIDE_INT ud1, ud2, ud3, ud4;
ud1 = c & 0xffff;
- c = c >> 16;
- ud2 = c & 0xffff;
- c = c >> 16;
- ud3 = c & 0xffff;
- c = c >> 16;
- ud4 = c & 0xffff;
+ ud2 = (c >> 16) & 0xffff;
+ ud3 = (c >> 32) & 0xffff;
+ ud4 = (c >> 48) & 0xffff;
if ((ud4 == 0xffff && ud3 == 0xffff && ud2 == 0xffff && (ud1 & 0x8000))
|| (ud4 == 0 && ud3 == 0 && ud2 == 0 && ! (ud1 & 0x8000)))
@@ -10278,6 +10316,19 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
emit_move_insn (dest, gen_rtx_XOR (DImode, temp,
GEN_INT ((ud2 ^ 0xffff) << 16)));
}
+ else if (can_be_built_by_li_and_rotldi (c, &shift, &mask))
+ {
+ temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
+ unsigned HOST_WIDE_INT imm = (c | ~mask);
+ imm = (imm >> shift) | (imm << (HOST_BITS_PER_WIDE_INT - shift));
+
+ emit_move_insn (temp, GEN_INT (imm));
+ if (shift != 0)
+ temp = gen_rtx_ROTATE (DImode, temp, GEN_INT (shift));
+ if (mask != HOST_WIDE_INT_M1)
+ temp = gen_rtx_AND (DImode, temp, GEN_INT (mask));
+ emit_move_insn (dest, temp);
+ }
else if (ud3 == 0 && ud4 == 0)
{
temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
new file mode 100644
@@ -0,0 +1,54 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -save-temps" } */
+/* { dg-require-effective-target has_arch_ppc64 } */
+
+#define NOIPA __attribute__ ((noipa))
+
+struct fun
+{
+ long long (*f) (void);
+ long long val;
+};
+
+long long NOIPA
+li_rotldi_1 (void)
+{
+ return 0x7531000000000LL;
+}
+
+long long NOIPA
+li_rotldi_2 (void)
+{
+ return 0x2100000000000064LL;
+}
+
+long long NOIPA
+li_rotldi_3 (void)
+{
+ return 0xffff8531ffffffffLL;
+}
+
+long long NOIPA
+li_rotldi_4 (void)
+{
+ return 0x21ffffffffffff94LL;
+}
+
+struct fun arr[] = {
+ {li_rotldi_1, 0x7531000000000LL},
+ {li_rotldi_2, 0x2100000000000064LL},
+ {li_rotldi_3, 0xffff8531ffffffffLL},
+ {li_rotldi_4, 0x21ffffffffffff94LL},
+};
+
+/* { dg-final { scan-assembler-times {\mrotldi\M} 4 } } */
+
+int
+main ()
+{
+ for (int i = 0; i < sizeof (arr) / sizeof (arr[0]); i++)
+ if ((*arr[i].f) () != arr[i].val)
+ __builtin_abort ();
+
+ return 0;
+}
Hi, This patch checks if a constant is possible to be rotated to/from a positive or negative value from "li". If so, we could use "li;rotldi" to build it. Bootstrap and regtest pass on ppc64{,le}. Is this ok for trunk or next stage1? BR, Jeff (Jiufu) gcc/ChangeLog: * config/rs6000/rs6000.cc (can_be_rotated_to_possitive_li): New function. (can_be_rotated_to_negative_li): New function. (can_be_built_by_li_and_rotldi): New function. (rs6000_emit_set_long_const): Call can_be_built_by_li_and_rotldi. gcc/testsuite/ChangeLog: * gcc.target/powerpc/const-build.c: New test. --- gcc/config/rs6000/rs6000.cc | 63 +++++++++++++++++-- .../gcc.target/powerpc/const-build.c | 54 ++++++++++++++++ 2 files changed, 111 insertions(+), 6 deletions(-) create mode 100644 gcc/testsuite/gcc.target/powerpc/const-build.c