Re: [PATCH V2] aarch64: Add missing ACLE macro for NEON-SVE Bridge

[Richard Ball]

v2: Change macro definition following internal discussion.

__ARM_NEON_SVE_BRIDGE was missed in the original patch and is
added by this patch.

Ok for trunk and a backport into gcc-14?

gcc/ChangeLog:

        * config/aarch64/aarch64-c.cc (aarch64_define_unconditional_macros):
        Add missing __ARM_NEON_SVE_BRIDGE.

On 6/6/24 13:20, Richard Sandiford wrote:
> Richard Ball <richard.b...@arm.com> writes:
>> __ARM_NEON_SVE_BRIDGE was missed in the original patch and is
>> added by this patch.
>>
>> Ok for trunk and a backport into gcc-14?
>>
>> gcc/ChangeLog:
>>
>>      * config/aarch64/aarch64-c.cc (aarch64_update_cpp_builtins):
>>      Add missing __ARM_NEON_SVE_BRIDGE.
> 
> After this patch was posted, there was some internal discussion
> involving LLVM & GNU devs about what this kind of macro means, now that
> we have FMV.  The feeling was that __ARM_NEON_SVE_BRIDGE should just
> indicate whether the compiler provides the file, not whether AdvSIMD
> & SVE are enabled.  I think we should therefore add this to
> aarch64_define_unconditional_macros instead.
> 
> Sorry for the slow review.  I was waiting for the outcome of that
> discussion before replying.
> 
> Thanks,
> Richard
> 
>> diff --git a/gcc/config/aarch64/aarch64-c.cc 
>> b/gcc/config/aarch64/aarch64-c.cc
>> index 
>> fe1a20e4e546a68e5f7eddff3bbb0d3e831fbd9b..1121be118cf8d05e3736ad4ee75568ff7cb92bfd
>>  100644
>> --- a/gcc/config/aarch64/aarch64-c.cc
>> +++ b/gcc/config/aarch64/aarch64-c.cc
>> @@ -260,6 +260,7 @@ aarch64_update_cpp_builtins (cpp_reader *pfile)
>>    aarch64_def_or_undef (TARGET_SME_I16I64, "__ARM_FEATURE_SME_I16I64", 
>> pfile);
>>    aarch64_def_or_undef (TARGET_SME_F64F64, "__ARM_FEATURE_SME_F64F64", 
>> pfile);
>>    aarch64_def_or_undef (TARGET_SME2, "__ARM_FEATURE_SME2", pfile);
>> +  aarch64_def_or_undef (TARGET_SVE, "__ARM_NEON_SVE_BRIDGE", pfile);
>>  
>>    /* Not for ACLE, but required to keep "float.h" correct if we switch
>>       target between implementations that do or do not support ARMv8.2-A
diff --git a/gcc/config/aarch64/aarch64-c.cc b/gcc/config/aarch64/aarch64-c.cc
index fe1a20e4e546a68e5f7eddff3bbb0d3e831fbd9b..d042e5fbd8c562df2e4538b51b960c194d2ca2c9 100644
--- a/gcc/config/aarch64/aarch64-c.cc
+++ b/gcc/config/aarch64/aarch64-c.cc
@@ -75,6 +75,7 @@ aarch64_define_unconditional_macros (cpp_reader *pfile)
 
   builtin_define ("__ARM_STATE_ZA");
   builtin_define ("__ARM_STATE_ZT0");
+  builtin_define ("__ARM_NEON_SVE_BRIDGE");
 
   /* Define keyword attributes like __arm_streaming as macros that expand
      to the associated [[...]] attribute.  Use __extension__ in the attribute