GCC:哪些目标支持定点类型？

Question

$ echo "_Fract x;" | gcc -xc -
<stdin>:1:1: error: fixed-point types not supported for this target

6.16定点类型 (重点后加)：

作为扩展，GNU支持N1169 /IEC 18037中定义的定点类型.GCC对固定点类型的支持将随着技术报告草稿的变化而发展.对任何目标的调用约定也可能发生更改。并不是所有目标都支持定点类型.

问:哪些目标支持定点类型？

额外的:有文件记录吗？如何从GCC的源代码中派生出来？

UPD。可能有用: Clang通过选项-ffixed-point支持定点类型。

$ echo "_Fract x;" | clang -xc - -c -ffixed-point
# OK

Answer 1

我可以确认GCC 11.2.0在AVR上确实支持定点类型.尺码如下：

sizeof(signed   short _Fract) == 1
sizeof(unsigned short _Fract) == 1

sizeof(signed   _Fract) == 2
sizeof(unsigned _Fract) == 2

sizeof(signed   long _Fract) == 4
sizeof(unsigned long _Fract) == 4

sizeof(signed   long long _Fract) == 8
sizeof(unsigned long long _Fract) == 8

sizeof(signed   short _Accum) == 2
sizeof(unsigned short _Accum) == 2

sizeof(signed   _Accum) == 4
sizeof(unsigned _Accum) == 4

sizeof(signed   long _Accum) == 8
sizeof(unsigned long _Accum) == 8

sizeof(signed   long long _Accum) == 8
sizeof(unsigned long long _Accum) == 8