On 02/12/2024 11:21, Christophe Lyon wrote:
> If the target does not support floating-point, we register FP vector
> types as 'void' (see register_vector_type).
>
> The leads to warnings about 'pure attribute on function returning
> void' when we declare the various load intrinsics because their
> call_properties say CP_READ_MEMORY (thus giving them the 'pure'
> attribute), but their return type is void.
>
> To avoid such warnings, pretend the call_properties are empty when FP
> is disabled and the function would return an FP value. If such
> functions are incorrectly used in user code, a proper error is
> emitted:
> unknown type name ‘float16x8_t'; did you mean ‘int16x8_t’?
>
> gcc/ChangeLog:
>
> PR target/117814
> * config/arm/arm-mve-builtins-base.cc (vld1_impl): Fix
> call_properties.
> (vld24_impl): Likewise.
> * config/arm/arm-mve-builtins-functions.h (load_extending):
> Likewise.
Won't this lead to problems if the code is something like
#include "arm_mve.h"
#pragma gcc target ("arch=armv8.1-m.main+mve.fp")
// Some use of an affected intrinsic
and then compile with "-march=armv8.1-m.main+mve -mfpu=auto -mfloat-abi=softfp"?
R.
> ---
> gcc/config/arm/arm-mve-builtins-base.cc | 22 +++++++++++++++++++--
> gcc/config/arm/arm-mve-builtins-functions.h | 11 ++++++++++-
> 2 files changed, 30 insertions(+), 3 deletions(-)
>
> diff --git a/gcc/config/arm/arm-mve-builtins-base.cc
> b/gcc/config/arm/arm-mve-builtins-base.cc
> index 723004b53d7..a322730eca8 100644
> --- a/gcc/config/arm/arm-mve-builtins-base.cc
> +++ b/gcc/config/arm/arm-mve-builtins-base.cc
> @@ -141,8 +141,17 @@ class vld1_impl : public full_width_access
> {
> public:
> unsigned int
> - call_properties (const function_instance &) const override
> + call_properties (const function_instance &instance) const override
> {
> + /* If the target does not support floating-point, we register FP vector
> + types as 'void'. In this case, pretend we do not access memory to
> avoid
> + warnings about 'pure attribute on function returning void' when we
> + declare the intrinsics. Such uses in user code are properly
> + diagnosed. */
> + if (!TARGET_HAVE_MVE_FLOAT
> + && instance.type_suffix (0).float_p)
> + return 0;
> +
> return CP_READ_MEMORY;
> }
>
> @@ -1141,8 +1150,17 @@ public:
> using full_width_access::full_width_access;
>
> unsigned int
> - call_properties (const function_instance &) const override
> + call_properties (const function_instance &instance) const override
> {
> + /* If the target does not support floating-point, we register FP vector
> + types as 'void'. In this case, pretend we do not access memory to
> avoid
> + warnings about 'pure attribute on function returning void' when we
> + declare the intrinsics. Such uses in user code are properly
> + diagnosed. */
> + if (!TARGET_HAVE_MVE_FLOAT
> + && instance.type_suffix (0).float_p)
> + return 0;
> +
> return CP_READ_MEMORY;
> }
>
> diff --git a/gcc/config/arm/arm-mve-builtins-functions.h
> b/gcc/config/arm/arm-mve-builtins-functions.h
> index 0ade2157e4a..1a9a347805c 100644
> --- a/gcc/config/arm/arm-mve-builtins-functions.h
> +++ b/gcc/config/arm/arm-mve-builtins-functions.h
> @@ -986,8 +986,17 @@ public:
> m_float_memory_type (NUM_TYPE_SUFFIXES)
> {}
>
> - unsigned int call_properties (const function_instance &) const override
> + unsigned int call_properties (const function_instance &instance) const
> override
> {
> + /* If the target does not support floating-point, we register FP vector
> + types as 'void'. In this case, pretend we do not access memory to
> avoid
> + warnings about 'pure attribute on function returning void' when we
> + declare the intrinsics. Such uses in user code are properly
> + diagnosed. */
> + if (!TARGET_HAVE_MVE_FLOAT
> + && instance.type_suffix (0).float_p)
> + return 0;
> +
> return CP_READ_MEMORY;
> }
>
