Hi Andrew!
On 2024-12-05T15:14:45+0100, I wrote:
> On 2020-01-31T11:20:14+0000, Andrew Stubbs <a...@codesourcery.com> wrote:
>> This is one of those things I don't know why we didn't notice sooner.
>
> ..., and here's another thing I don't know why we didn't notice sooner.
> ;-P (Category: "don't we all love C++?!")
>
>> [...]
>> I also needed a convenient way to create 0.0 vector constants without
>> uglifying the machine description code, so extending gcn_vec_constant
>> seemed like a useful place to do it.
>
>> --- a/gcc/config/gcn/gcn.c
>> +++ b/gcc/config/gcn/gcn.c
>> @@ -992,9 +992,19 @@ gcn_vec_constant (machine_mode mode, int a)
>> return CONST2_RTX (mode);*/
>>
>> int units = GET_MODE_NUNITS (mode);
>> - rtx tem = gen_int_mode (a, GET_MODE_INNER (mode));
>> - rtvec v = rtvec_alloc (units);
>> + machine_mode innermode = GET_MODE_INNER (mode);
>> +
>> + rtx tem;
>> + if (FLOAT_MODE_P (innermode))
>> + {
>> + REAL_VALUE_TYPE rv;
>> + real_from_integer (&rv, NULL, a, SIGNED);
>> + tem = const_double_from_real_value (rv, innermode);
>> + }
>> + else
>> + tem = gen_int_mode (a, innermode);
>>
>> + rtvec v = rtvec_alloc (units);
>> for (int i = 0; i < units; ++i)
>> RTVEC_ELT (v, i) = tem;
>
> That's apparently not the proper way to use 'real_from_integer'. Its
> second argument is a 'format_helper', which is a class defined in
> 'gcc/real.h', which has a templated constructor that is meant to receive
> a mode, so instead of 'NULL', this should pass in 'VOIDmode' (correct?).
> Anyway: until recently, this appeared to work (fine?) -- but broke with
> Andrew Pinski's recent commit b3f1b9e2aa079f8ec73e3cb48143a16645c49566
> "build: Remove INCLUDE_MEMORY [PR117737]":
>
> [...]
> In file included from ../../source-gcc/gcc/coretypes.h:507:0,
> from ../../source-gcc/gcc/config/gcn/gcn.cc:24:
> ../../source-gcc/gcc/real.h: In instantiation of
> ‘format_helper::format_helper(const T&) [with T = std::nullptr_t]’:
> ../../source-gcc/gcc/config/gcn/gcn.cc:1178:46: required from here
> ../../source-gcc/gcc/real.h:233:17: error: no match for ‘operator==’
> (operand types are ‘std::nullptr_t’ and ‘machine_mode’)
> : m_format (m == VOIDmode ? 0 : REAL_MODE_FORMAT (m))
> ^
> [...]
>
> Andrew P.'s commit doesn't touch 'gcc/config/gcn/gcn.cc'; the only part
> relevant here -- per my understanding -- should be:
>
> --- gcc/system.h
> +++ gcc/system.h
> @@ -224,0 +225 @@ extern int fprintf_unlocked (FILE *, const char *, ...);
> +# include <memory>
> @@ -761,7 +761,0 @@ private:
> -/* Some of the headers included by <memory> can use "abort" within a
> - namespace, e.g. "_VSTD::abort();", which fails after we use the
> - preprocessor to redefine "abort" as "fancy_abort" below. */
> -
> -#ifdef INCLUDE_MEMORY
> -# include <memory>
> -#endif
>
> In other words, (unconditional) '#include <memory>' appears to preclude
> ability to convert 'NULL' into a mode? (Or, I'm off-track, of course...)
>
> Either way: OK to push the attached "GCN: Fix 'real_from_integer' usage"
> after testing completes?
No issues found in testing.
Grüße
Thomas
>From dfc2a5398979738ae25eb0258bbf64b82df621a5 Mon Sep 17 00:00:00 2001
From: Thomas Schwinge <tschwi...@baylibre.com>
Date: Thu, 5 Dec 2024 14:28:26 +0100
Subject: [PATCH] GCN: Fix 'real_from_integer' usage
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
The recent commit b3f1b9e2aa079f8ec73e3cb48143a16645c49566
"build: Remove INCLUDE_MEMORY [PR117737]" exposed an issue in code added in
2020 GCN back end commit 95607c12363712c39345e1d97f2c1aee8025e188
"Zero-initialise masked load destinations"; compilation now fails:
[...]
In file included from ../../source-gcc/gcc/coretypes.h:507:0,
from ../../source-gcc/gcc/config/gcn/gcn.cc:24:
../../source-gcc/gcc/real.h: In instantiation of ‘format_helper::format_helper(const T&) [with T = std::nullptr_t]’:
../../source-gcc/gcc/config/gcn/gcn.cc:1178:46: required from here
../../source-gcc/gcc/real.h:233:17: error: no match for ‘operator==’ (operand types are ‘std::nullptr_t’ and ‘machine_mode’)
: m_format (m == VOIDmode ? 0 : REAL_MODE_FORMAT (m))
^
[...]
That's with 'g++ (GCC) 5.5.0', and seen similarly with
'g++ (Ubuntu 9.4.0-1ubuntu1~20.04.2) 9.4.0', for example.
gcc/
* config/gcn/gcn.cc (gcn_vec_constant): Fix 'real_from_integer'
usage.
---
gcc/config/gcn/gcn.cc | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gcc/config/gcn/gcn.cc b/gcc/config/gcn/gcn.cc
index d078392eeaf1..b60835d8df48 100644
--- a/gcc/config/gcn/gcn.cc
+++ b/gcc/config/gcn/gcn.cc
@@ -1175,7 +1175,7 @@ gcn_vec_constant (machine_mode mode, int a)
if (FLOAT_MODE_P (innermode))
{
REAL_VALUE_TYPE rv;
- real_from_integer (&rv, NULL, a, SIGNED);
+ real_from_integer (&rv, VOIDmode, a, SIGNED);
tem = const_double_from_real_value (rv, innermode);
}
else
--
2.34.1
