Re: [PATCH 1/3] expr: Allow scalar_int_mode target mode when converting a constant
Jozef Lawrynowicz writes: > On Wed, Jul 22, 2020 at 09:33:47AM +0100, Richard Sandiford wrote: >> Jozef Lawrynowicz writes: >> > is_int_mode does not allow MODE_PARTIAL_INT modes, so convert_modes was >> > not allowing a constant value to be converted to a MODE_PARTIAL_INT for >> > use as operand 2 in patterns such as ashlpsi3. The constant had >> > to be copied into a register before it could be used, but now can be >> > used directly as an operand without any copying. >> >> Yeah. I guess this dates back to when MODE_PARTIAL_INTs didn't have >> a known precision. > > Is that what the section on MODE_PARTIAL_INT in the description for the > "subreg" RTX refers to? From "14.8 Registers and Memory" of gccint: > > A MODE_PARTIAL_INT mode behaves as if it were as wide as the corresponding > MODE_INT mode, except that it has an unknown number of undefined bits. Yeah. Before d8487c949ad5 the number of significant bits in a partial mode was hidden from target-independent code. > If so, that whole section seems out of date. I can work on getting it > fixed up. Sounds good :-) Thanks, Richard
Re: [PATCH 1/3] expr: Allow scalar_int_mode target mode when converting a constant
On Wed, Jul 22, 2020 at 09:33:47AM +0100, Richard Sandiford wrote:
> Jozef Lawrynowicz writes:
> > is_int_mode does not allow MODE_PARTIAL_INT modes, so convert_modes was
> > not allowing a constant value to be converted to a MODE_PARTIAL_INT for
> > use as operand 2 in patterns such as ashlpsi3. The constant had
> > to be copied into a register before it could be used, but now can be
> > used directly as an operand without any copying.
>
> Yeah. I guess this dates back to when MODE_PARTIAL_INTs didn't have
> a known precision.
Is that what the section on MODE_PARTIAL_INT in the description for the
"subreg" RTX refers to? From "14.8 Registers and Memory" of gccint:
A MODE_PARTIAL_INT mode behaves as if it were as wide as the corresponding
MODE_INT mode, except that it has an unknown number of undefined bits.
If so, that whole section seems out of date. I can work on getting it
fixed up.
>
> > diff --git a/gcc/expr.c b/gcc/expr.c
> > index c7c3e9fd655..5a252f0935f 100644
> > --- a/gcc/expr.c
> > +++ b/gcc/expr.c
> > @@ -696,7 +696,7 @@ convert_modes (machine_mode mode, machine_mode oldmode,
> > rtx x, int unsignedp)
> > return x;
> >
> >if (CONST_SCALAR_INT_P (x)
> > - && is_int_mode (mode, &int_mode))
> > + && is_a (mode, &int_mode))
> > {
> >/* If the caller did not tell us the old mode, then there is not
> > much to do with respect to canonicalization. We have to
>
> I think we also need to change the condition in:
>
> /* If the caller did not tell us the old mode, then there is not
>much to do with respect to canonicalization. We have to
>assume that all the bits are significant. */
> if (GET_MODE_CLASS (oldmode) != MODE_INT)
>
> to is_a (old_mode)
>
> OK with that, thanks.
Thanks, I'll regtest that change and apply if all looks good.
Jozef
>
> Richard
Re: [PATCH 1/3] expr: Allow scalar_int_mode target mode when converting a constant
Jozef Lawrynowicz writes:
> is_int_mode does not allow MODE_PARTIAL_INT modes, so convert_modes was
> not allowing a constant value to be converted to a MODE_PARTIAL_INT for
> use as operand 2 in patterns such as ashlpsi3. The constant had
> to be copied into a register before it could be used, but now can be
> used directly as an operand without any copying.
Yeah. I guess this dates back to when MODE_PARTIAL_INTs didn't have
a known precision.
> diff --git a/gcc/expr.c b/gcc/expr.c
> index c7c3e9fd655..5a252f0935f 100644
> --- a/gcc/expr.c
> +++ b/gcc/expr.c
> @@ -696,7 +696,7 @@ convert_modes (machine_mode mode, machine_mode oldmode,
> rtx x, int unsignedp)
> return x;
>
>if (CONST_SCALAR_INT_P (x)
> - && is_int_mode (mode, &int_mode))
> + && is_a (mode, &int_mode))
> {
>/* If the caller did not tell us the old mode, then there is not
>much to do with respect to canonicalization. We have to
I think we also need to change the condition in:
/* If the caller did not tell us the old mode, then there is not
much to do with respect to canonicalization. We have to
assume that all the bits are significant. */
if (GET_MODE_CLASS (oldmode) != MODE_INT)
to is_a (old_mode)
OK with that, thanks.
Richard
[PATCH 1/3] expr: Allow scalar_int_mode target mode when converting a constant
is_int_mode does not allow MODE_PARTIAL_INT modes, so convert_modes was
not allowing a constant value to be converted to a MODE_PARTIAL_INT for
use as operand 2 in patterns such as ashlpsi3. The constant had
to be copied into a register before it could be used, but now can be
used directly as an operand without any copying.
Successfully regtested on trunk for x86_64-pc-linux-gnu and msp430-elf.
Ok to apply?
>From 485feafad6ef0966ff0e1d2ae383cd2b6dbc5c96 Mon Sep 17 00:00:00 2001
From: Jozef Lawrynowicz
Date: Wed, 15 Jul 2020 11:19:16 +0100
Subject: [PATCH 1/3] expr: Allow scalar_int_mode target mode when converting a
constant
is_int_mode does not allow MODE_PARTIAL_INT modes, so convert_modes was
not allowing a constant value to be converted to a MODE_PARTIAL_INT for
use as operand 2 in patterns such as ashlpsi3. The constant had
to be copied into a register before it could be used, but now can be
used directly as an operand without any copying.
gcc/ChangeLog:
* expr.c (convert_modes): Allow a constant integer to be converted to
any scalar int mode.
---
gcc/expr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gcc/expr.c b/gcc/expr.c
index c7c3e9fd655..5a252f0935f 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -696,7 +696,7 @@ convert_modes (machine_mode mode, machine_mode oldmode, rtx
x, int unsignedp)
return x;
if (CONST_SCALAR_INT_P (x)
- && is_int_mode (mode, &int_mode))
+ && is_a (mode, &int_mode))
{
/* If the caller did not tell us the old mode, then there is not
much to do with respect to canonicalization. We have to
--
2.27.0
