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Re: [RFC] PR 58542: const_int vs lost modes
- From: Richard Sandiford <rsandifo at linux dot vnet dot ibm dot com>
- To: Eric Botcazou <ebotcazou at adacore dot com>
- Cc: Richard Henderson <rth at redhat dot com>, gcc-patches at gcc dot gnu dot org
- Date: Thu, 24 Oct 2013 13:02:55 +0100
- Subject: Re: [RFC] PR 58542: const_int vs lost modes
- Authentication-results: sourceware.org; auth=none
- References: <52686543 dot 1000506 at redhat dot com> <2249166 dot AW8VGR967l at polaris> <2705096 dot z4dVz8XuFW at polaris>
Eric Botcazou <ebotcazou@adacore.com> writes:
>> That's a fairly dangerous hack in my opinion, in particular this breaks the
>> uniqueness of representation of -1 as constm1_rtx. Can't we find a really
>> contained hack instead, especially if we want to backport it to 4.8?
>
> In particular, can't Uros' patch be considered as such here? Frankly, the
> choice of 'true' vs 'false' for create_convert_operand_to in optabs isn't
> crystal clear...
Do we actually need to do a conversion here at all? It looks like the
modes of "expected" and "desired" should already match "mem", so we could
just use create_input_operand.
Thanks,
Richard