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* [gcc(refs/users/meissner/heads/work056)] PR 101019: Improve loading 64-bit constants on power10.
@ 2021-06-18 4:55 Michael Meissner
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From: Michael Meissner @ 2021-06-18 4:55 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:6305b55e8686a1d709876e6210ce4a47d0dd294f
commit 6305b55e8686a1d709876e6210ce4a47d0dd294f
Author: Michael Meissner <meissner@linux.ibm.com>
Date: Fri Jun 18 00:55:16 2021 -0400
PR 101019: Improve loading 64-bit constants on power10.
When the support for prefixed instructions went into GCC, we did not
modify loading up larger constants to use one or two PLI/PADDI
instructions. This patch adds this support.
gcc/
2021-06-18 Michael Meissner <meissner@linux.ibm.com>
PR target/101019
* config/rs6000/rs6000-cpus.def (ISA_3_1_MASKS_SERVER): Add
-mpower10-large-consts support.
(POWERPC_MASKS): Add -mpower10-large-consts support.
* config/rs6000/rs6000.c (rs6000_option_override_internal): Add
-mpower10-large-consts support.
(num_insns_constant_gpr): Add -mpower10-large-consts support.
(rs6000_emit_set_long_const): Add -mpower10-large-consts support.
(rs6000_opt_masks): Add -mpower10-large-consts.
* config/rs6000/rs6000.opt (-mpower10-large-consts): New switch.
gcc/testsuite/
2021-06-18 Michael Meissner <meissner@linux.ibm.com>
PR target/101019
* gcc.target/powerpc/prefix-large-const.c: New test.
Diff:
---
gcc/config/rs6000/rs6000-cpus.def | 2 +
gcc/config/rs6000/rs6000.c | 67 ++++++++++++++++++++--
gcc/config/rs6000/rs6000.opt | 4 ++
.../gcc.target/powerpc/prefix-large-const.c | 57 ++++++++++++++++++
4 files changed, 126 insertions(+), 4 deletions(-)
diff --git a/gcc/config/rs6000/rs6000-cpus.def b/gcc/config/rs6000/rs6000-cpus.def
index c0d89434fcd..b119f574e4c 100644
--- a/gcc/config/rs6000/rs6000-cpus.def
+++ b/gcc/config/rs6000/rs6000-cpus.def
@@ -90,6 +90,7 @@
| OPTION_MASK_P10_FUSION_LOGADD \
| OPTION_MASK_P10_FUSION_ADDLOG \
| OPTION_MASK_P10_FUSION_2ADD \
+ | OPTION_MASK_P10_LARGE_CONSTS \
| OPTION_MASK_XXSPLTI32DX \
| OPTION_MASK_XXSPLTIDP \
| OPTION_MASK_XXSPLTIW)
@@ -145,6 +146,7 @@
| OPTION_MASK_P10_FUSION_LOGADD \
| OPTION_MASK_P10_FUSION_ADDLOG \
| OPTION_MASK_P10_FUSION_2ADD \
+ | OPTION_MASK_P10_LARGE_CONSTS \
| OPTION_MASK_HTM \
| OPTION_MASK_ISEL \
| OPTION_MASK_LXVKQ \
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index d34d8ba0ce9..01a586e1b14 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -4489,6 +4489,12 @@ rs6000_option_override_internal (bool global_init_p)
&& (rs6000_isa_flags_explicit & OPTION_MASK_P10_FUSION_2ADD) == 0)
rs6000_isa_flags |= OPTION_MASK_P10_FUSION_2ADD;
+ if (TARGET_PREFIXED
+ && (rs6000_isa_flags_explicit & OPTION_MASK_P10_LARGE_CONSTS) == 0)
+ rs6000_isa_flags |= OPTION_MASK_P10_LARGE_CONSTS;
+ else if (!TARGET_PREFIXED)
+ rs6000_isa_flags &= ~OPTION_MASK_P10_LARGE_CONSTS;
+
/* Turn off vector pair/mma options on non-power10 systems. */
else if (!TARGET_POWER10 && TARGET_MMA)
{
@@ -5964,9 +5970,20 @@ num_insns_constant_gpr (HOST_WIDE_INT value)
&& (value >> 31 == -1 || value >> 31 == 0))
return 1;
- /* PADDI can support up to 34 bit signed integers. */
- else if (TARGET_PREFIXED && SIGNED_INTEGER_34BIT_P (value))
- return 1;
+ /* PADDI can support up to 34 bit signed integers, or using a combination of
+ PADDI and shift left. */
+ else if (TARGET_P10_LARGE_CONSTS)
+ {
+ if (SIGNED_INTEGER_34BIT_P (value))
+ return 1;
+
+ /* PLI and SLDI. */
+ if ((value & 0xffffffff) == 0)
+ return 2;
+
+ /* PLI, SLDI, PADDI. */
+ return 3;
+ }
else if (TARGET_POWERPC64)
{
@@ -10420,7 +10437,48 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
rtx two = gen_rtx_ASHIFT (DImode, temp, GEN_INT (32));
emit_move_insn (dest, gen_rtx_IOR (DImode, one, two));
}
- else if ((ud4 == 0xffff && (ud3 & 0x8000))
+ else if (TARGET_P10_LARGE_CONSTS)
+ {
+ HOST_WIDE_INT low_32bit = ud1 | (ud2 << 16);
+ HOST_WIDE_INT high_32bit = ud3 | (ud4 << 16);
+
+ temp = !can_create_pseudo_p () ? copy_rtx (dest) : gen_reg_rtx (DImode);
+ emit_move_insn (temp, GEN_INT (high_32bit));
+
+ if (!low_32bit)
+ emit_insn (gen_ashldi3 (dest, temp, GEN_INT (32)));
+ else
+ {
+ rtx temp2 = (!can_create_pseudo_p ()
+ ? copy_rtx (dest)
+ : gen_reg_rtx (DImode));
+
+ emit_insn (gen_ashldi3 (temp2, temp, GEN_INT (32)));
+
+ /* See if a simple ORI or ORIS will suffice to fill in the
+ constant. */
+ if (ud2 == 0)
+ emit_insn (gen_iordi3 (dest, temp2, GEN_INT (ud1)));
+ else if (ud1 == 0)
+ emit_insn (gen_iordi3 (dest, temp2, GEN_INT (ud2 << 16)));
+ /* If the register is not r0, we can do a PADDI. However, if the
+ register is r0, we need to do an ORI and ORIS instead of a PADDI.
+ This is because R0 as the register is interpreted as 0 and not
+ R0. */
+ else if (REGNO (dest) != FIRST_GPR_REGNO)
+ emit_insn (gen_adddi3 (dest, temp2, GEN_INT (low_32bit)));
+ else
+ {
+ rtx temp3 = (!can_create_pseudo_p ()
+ ? copy_rtx (dest)
+ : gen_reg_rtx (DImode));
+
+ emit_insn (gen_iordi3 (temp3, temp2, GEN_INT (ud2 << 16)));
+ emit_insn (gen_iordi3 (dest, temp3, GEN_INT (ud1)));
+ }
+ }
+ }
+ else if ((ud4 == 0xaffff && (ud3 & 0x8000))
|| (ud4 == 0 && ! (ud3 & 0x8000)))
{
temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
@@ -24432,6 +24490,7 @@ static struct rs6000_opt_mask const rs6000_opt_masks[] =
{ "power9-misc", OPTION_MASK_P9_MISC, false, true },
{ "power9-vector", OPTION_MASK_P9_VECTOR, false, true },
{ "power10-fusion", OPTION_MASK_P10_FUSION, false, true },
+ { "power10-large-consts", OPTION_MASK_P10_LARGE_CONSTS, false, true },
{ "powerpc-gfxopt", OPTION_MASK_PPC_GFXOPT, false, true },
{ "powerpc-gpopt", OPTION_MASK_PPC_GPOPT, false, true },
{ "prefixed", OPTION_MASK_PREFIXED, false, true },
diff --git a/gcc/config/rs6000/rs6000.opt b/gcc/config/rs6000/rs6000.opt
index e65dd8762a4..add22c8be1a 100644
--- a/gcc/config/rs6000/rs6000.opt
+++ b/gcc/config/rs6000/rs6000.opt
@@ -655,3 +655,7 @@ Generate (do not generate) XXSPLTI32DX instructions.
mlxvkq
Target Undocumented Mask(LXVKQ) Var(rs6000_isa_flags)
Generate (do not generate) LXVKQ instructions.
+
+mpower10-large-consts
+Target Undocumented Mask(P10_LARGE_CONSTS) Var(rs6000_isa_flags)
+Generate (do not generate) PLI/SLDI/PADDI to load large constants.
diff --git a/gcc/testsuite/gcc.target/powerpc/prefix-large-const.c b/gcc/testsuite/gcc.target/powerpc/prefix-large-const.c
new file mode 100644
index 00000000000..df0e333d148
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/prefix-large-const.c
@@ -0,0 +1,57 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target powerpc_prefixed_addr } */
+/* { dg-require-effective-target lp64 } */
+/* { dg-options "-O2 -mdejagnu-cpu=power10" } */
+
+/* Test whether we can use PLI/PADDI to load up large constants. */
+
+long
+foo_1 (void)
+{
+ return 1L << 53; /* LIS, SLDI. */
+}
+
+long
+foo_2 (void)
+{
+ return 1L << 34; /* LI, SLDI. */
+}
+
+long
+foo_3 (void)
+{
+ return (1L << 53) | (1L << 35); /* PLI, SLDI. */
+}
+
+long
+foo_4 (void)
+{
+ return ((1L << 53) /* PLI, SLDI, PADDI. */
+ | (1L << 35)
+ | (1L << 30)
+ | (1L << 2));
+}
+
+long
+foo_5 (void)
+{
+ return ((1L << 53) /* PLI, SLDI, ORI. */
+ | (1L << 35)
+ | (1L << 2));
+}
+
+long
+foo_6 (void)
+{
+ return ((1L << 53) /* PLI, SLDI, ORIS. */
+ | (1L << 35)
+ | (1L << 30));
+}
+
+/* { dg-final { scan-assembler-times {\mli\M} 1 } } */
+/* { dg-final { scan-assembler-times {\mlis\M} 1 } } */
+/* { dg-final { scan-assembler-times {\mori\M} 1 } } */
+/* { dg-final { scan-assembler-times {\moris\M} 1 } } */
+/* { dg-final { scan-assembler-times {\mpaddi\M} 1 } } */
+/* { dg-final { scan-assembler-times {\mpli\M} 4 } } */
+/* { dg-final { scan-assembler-times {\msldi\M} 6 } } */
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