Hi!
On Sun, Feb 26, 2023 at 01:10:41PM -, Roger Sayle wrote:
> This patch teaches simplify-rtx.cc to err on the side of caution, by never
> creating (new) FFS, POPCOUNT or PARITY rtx with mismatched modes,
> matching the documentation.
> * simplify-rtx.cc (simplify_unary_operation_1)
39
> To: Jeff Law ; 'Segher Boessenkool'
> ; Roger Sayle
> Cc: 'GCC Patches'
> Subject: Re: [PATCH] Fix RTL simplifications of FFS, POPCOUNT and PARITY.
>
> On Sun, Jan 01, 2023 at 03:55:26PM -, Roger Sayle wrote:
> > In 2011, the rtl.texi documentation
On Sun, Jan 01, 2023 at 03:55:26PM -, Roger Sayle wrote:
> In 2011, the rtl.texi documentation was updated to reflect that the
> modes of the RTX unary operations FFS, POPCOUNT and PARITY must
> match those of their operands. Unfortunately, some of the transformations
> in simplify-rtx.cc pred
On Mon, Jan 02, 2023 at 09:20:33AM -0700, Jeff Law wrote:
> On 1/2/23 08:59, Jakub Jelinek wrote:
> >See the PR50161 thread in
> >https://gcc.gnu.org/legacy-ml/gcc-patches/2011-08/threads.html#01847
Nasty nasty nasty.
> >The options are to disallow different modes, which is what my patch did
> >(
On 1/2/23 10:30, ro...@nextmovesoftware.com wrote:
Hi Jeff,
On 2 Jan 2023, at 15:45, Jeff Law wrote:
On 1/1/23 08:55, Roger Sayle wrote:
In 2011, the rtl.texi documentation was updated to reflect that the
modes of the RTX unary operations FFS, POPCOUNT and PARITY must
match those of their
On 1/2/23 10:22, Jakub Jelinek wrote:
On Mon, Jan 02, 2023 at 09:20:33AM -0700, Jeff Law wrote:
In fact Raphael and I were about to submit a patch which takes advantage of
that capability to improve the code slightly for risc-v.
Just use a pattern with zero_extend or sign_extend around it o
Hi Jeff,
> On 2 Jan 2023, at 15:45, Jeff Law wrote:
> On 1/1/23 08:55, Roger Sayle wrote:
>> In 2011, the rtl.texi documentation was updated to reflect that the
>> modes of the RTX unary operations FFS, POPCOUNT and PARITY must
>> match those of their operands. Unfortunately, some of the trans
On Mon, Jan 02, 2023 at 09:20:33AM -0700, Jeff Law wrote:
> > > In fact Raphael and I were about to submit a patch which takes advantage
> > > of
> > > that capability to improve the code slightly for risc-v.
> >
> > Just use a pattern with zero_extend or sign_extend around it or subreg of
> > it
On 1/2/23 08:59, Jakub Jelinek wrote:
On Mon, Jan 02, 2023 at 08:45:15AM -0700, Jeff Law via Gcc-patches wrote:
On 1/1/23 08:55, Roger Sayle wrote:
In 2011, the rtl.texi documentation was updated to reflect that the
modes of the RTX unary operations FFS, POPCOUNT and PARITY must
match those
On Mon, Jan 02, 2023 at 08:45:15AM -0700, Jeff Law via Gcc-patches wrote:
> On 1/1/23 08:55, Roger Sayle wrote:
> > In 2011, the rtl.texi documentation was updated to reflect that the
> > modes of the RTX unary operations FFS, POPCOUNT and PARITY must
> > match those of their operands. Unfortunate
On 1/1/23 08:55, Roger Sayle wrote:
In 2011, the rtl.texi documentation was updated to reflect that the
modes of the RTX unary operations FFS, POPCOUNT and PARITY must
match those of their operands. Unfortunately, some of the transformations
in simplify-rtx.cc predate this tightening of RTL s
The motivation for the current design (requiring the result and the operand to
have
the same mode) was from PR middle-end/50161. The challenge there is that when
the RTL optimizers can determine that the operand is a constant, simplify_rtx
sees
just a CONST_INT with VOIDmode and therefore does
Hi!
On Sun, Jan 01, 2023 at 03:55:26PM -, Roger Sayle wrote:
> In 2011, the rtl.texi documentation was updated to reflect that the
> modes of the RTX unary operations FFS, POPCOUNT and PARITY must
> match those of their operands.
Is that not a limitation we should try to get rid of? It does
In 2011, the rtl.texi documentation was updated to reflect that the
modes of the RTX unary operations FFS, POPCOUNT and PARITY must
match those of their operands. Unfortunately, some of the transformations
in simplify-rtx.cc predate this tightening of RTL semantics, and have
not (until now) been u
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