Thanks for your comment!
Date: Wed, 30 Nov 2022 12:30:02 +0800
Message-ID: <7ebkopxdx1....@pike.rch.stglabs.ibm.com>
Segher Boessenkool <seg...@kernel.crashing.org> writes:
>> > + else if ((ud4 == 0xffff && ud3 == 0xffff)
>> > + && ((ud1 & 0x8000) || (ud1 == 0 && !(ud2 & 0x8000))))
>> > + {
>> > + temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
>> > +
>> > + HOST_WIDE_INT imm = (ud1 & 0x8000) ? ((ud1 ^ 0x8000) - 0x8000)
>> > + : ((ud2 << 16) - 0x80000000);
>
> We really should have some "hwi::sign_extend (ud1, 16)" helper function,
> heh. Maybe there already is? Ah, "sext_hwi". Fixing that up
> everywhere in this function is preapproved.
I drafted a seperate patch for this like below. Maybe I could update other
code like "((v & 0xf..f) ^ 0x80..0) - 0x80..0" in rs6000.cc and rs6000.md
with sext_hwi too.
BR,
Jeff (Jiufu)
Below NFC patch just uses sext_hwi to hand expresion like:
(xx ^ 0x80..0) - 0x80..0 in rs6000_emit_set_long_const.
---
gcc/config/rs6000/rs6000.cc | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)
diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 5efe9b22d8b..b03e059222b 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -10242,7 +10242,7 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
if ((ud4 == 0xffff && ud3 == 0xffff && ud2 == 0xffff && (ud1 & 0x8000))
|| (ud4 == 0 && ud3 == 0 && ud2 == 0 && ! (ud1 & 0x8000)))
- emit_move_insn (dest, GEN_INT ((ud1 ^ 0x8000) - 0x8000));
+ emit_move_insn (dest, GEN_INT (sext_hwi (ud1, 16)));
else if ((ud4 == 0xffff && ud3 == 0xffff && (ud2 & 0x8000))
|| (ud4 == 0 && ud3 == 0 && ! (ud2 & 0x8000)))
@@ -10250,7 +10250,7 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
emit_move_insn (ud1 != 0 ? copy_rtx (temp) : dest,
- GEN_INT (((ud2 << 16) ^ 0x80000000) - 0x80000000));
+ GEN_INT (sext_hwi (ud2 << 16, 32)));
if (ud1 != 0)
emit_move_insn (dest,
gen_rtx_IOR (DImode, copy_rtx (temp),
@@ -10261,8 +10261,7 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
gcc_assert (ud2 & 0x8000);
- emit_move_insn (copy_rtx (temp),
- GEN_INT (((ud2 << 16) ^ 0x80000000) - 0x80000000));
+ emit_move_insn (copy_rtx (temp), GEN_INT (sext_hwi (ud2 << 16, 32)));
if (ud1 != 0)
emit_move_insn (copy_rtx (temp),
gen_rtx_IOR (DImode, copy_rtx (temp),
@@ -10273,7 +10272,7 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
{
temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
HOST_WIDE_INT num = (ud2 << 16) | ud1;
- rs6000_emit_set_long_const (temp, (num ^ 0x80000000) - 0x80000000);
+ rs6000_emit_set_long_const (temp, sext_hwi (num, 32));
rtx one = gen_rtx_AND (DImode, temp, GEN_INT (0xffffffff));
rtx two = gen_rtx_ASHIFT (DImode, temp, GEN_INT (32));
emit_move_insn (dest, gen_rtx_IOR (DImode, one, two));
@@ -10283,8 +10282,7 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
{
temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
- emit_move_insn (copy_rtx (temp),
- GEN_INT (((ud3 << 16) ^ 0x80000000) - 0x80000000));
+ emit_move_insn (copy_rtx (temp), GEN_INT (sext_hwi (ud3 << 16, 32)));
if (ud2 != 0)
emit_move_insn (copy_rtx (temp),
gen_rtx_IOR (DImode, copy_rtx (temp),
@@ -10336,8 +10334,7 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
{
temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
- emit_move_insn (copy_rtx (temp),
- GEN_INT (((ud4 << 16) ^ 0x80000000) - 0x80000000));
+ emit_move_insn (copy_rtx (temp), GEN_INT (sext_hwi (ud4 << 16, 32)));
if (ud3 != 0)
emit_move_insn (copy_rtx (temp),
gen_rtx_IOR (DImode, copy_rtx (temp),
--
2.17.1
>
>> > + else
>> > + {
>> > + emit_move_insn (temp,
>> > + GEN_INT (((ud2 << 16) ^ 0x80000000) - 0x80000000));
>> > + 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)));
>> > + }
>
> Why this? Please just write it in DImode, do not go via SImode?
>
>> > --- /dev/null
>> > +++ b/gcc/testsuite/gcc.target/powerpc/pr106708.h
>> > @@ -0,0 +1,9 @@
>> > +/* Test constants which can be built by li/lis + oris/xoris */
>> > +void __attribute__ ((__noinline__, __noclone__)) foo (long long *arg)
>> > +{
>> > + *arg++ = 0x98765432ULL;
>> > + *arg++ = 0xffffffff7cdeab55ULL;
>> > + *arg++ = 0xffffffff65430000ULL;
>> > +}
>
> Use noipa please (it is shorter, simpler, and covers more :-) )
>
> Could you comment what exact instructions are expected?
> li;xoris and li;xoris and lis;xoris I guess? It helps if you just tell
> the reader here.
>
> The li;oris and li;xoris parts look good.
>
>
> Segher
