| commit | f9f5e9c36d0f7a56d3714b3179c2d8d41a57ee80 | |
| author | jsm28 <jsm28@138bc75d-0d04-0410-961f-82ee72b054a4> | |
| Wed, 21 Mar 2018 22:29:37 +0000 (21 22:29 +0000) | ||
| committer | jsm28 <jsm28@138bc75d-0d04-0410-961f-82ee72b054a4> | |
| Wed, 21 Mar 2018 22:29:37 +0000 (21 22:29 +0000) | ||
| tree | a1c2dc12c2981309138920b82613f39bb26024b4 | treesnapshot (tar.gz zip) |
| parent | c89e1f1ace950c17bebf377cbf4f8e0af8d398b3 | commitdiff |
Adjust __builtin_tgmath handling of integer arguments to _FloatN narrowing macros.
When adding __builtin_tgmath to support a better tgmath.h
implementation, I noted that further changes might be needed regarding
the TS 18661 functions that round their results to a narrower type,
because of unresolved issues with how the corresponding type-generic
macros are defined in TS 18661.
The resolution of those issues is still in flux, but the latest
version does indeed require something slightly different from
__builtin_tgmath. It specifies that integer arguments to type-generic
macros such as f32xadd are treated as _Float64 not double - which was
also present in earlier versions of the resolution - but then it also
specifies different handling for _Float64 arguments and double
arguments, which wasn't in earlier versions. Specifically, in the
latest version
<http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2213.pdf>, f32xadd
with _Float64 arguments would call f32xaddf64, while f32xadd with
double arguments would call f32xaddf64x. Since integer arguments are
converted directly to the argument type of the selected function (not
to double / _Float64x unless that ends up as the argument type), this
is a user-visible difference in semantics that means __builtin_tgmath
actually needs to implement treating integer arguments as _Float64 in
this case (the rest of the latest semantics can then be implemented in
the header, with a few inline functions there).
To avoid releasing with the older version of the __builtin_tgmath
semantics that doesn't work with the latest proposed DR#13 resolution,
this patch implements a rule in __builtin_tgmath that maps integer
types to _Float64 (respectively _Complex _Float64 for complex integer
types) where all the specified functions return the same _FloatN or
_FloatNx type. This does not affect any existing uses of
__builtin_tgmath in glibc's or GCC's tgmath.h since I haven't yet
added any of these type-generic macros to glibc when adding the
corresponding narrowing functions.
Bootstrapped with no regressions on x86_64-pc-linux-gnu.
* doc/extend.texi (__builtin_tgmath): Document when complex
integer types are treated as _Complex _Float64.
gcc/c:
* c-parser.c (c_parser_postfix_expression): For __builtin_tgmath
where all functions return the same _FloatN or _FloatNx type,
treat integer types as _Float64 instead of double.
gcc/testsuite:
* gcc.dg/builtin-tgmath-3.c: New test.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@258751 138bc75d-0d04-0410-961f-82ee72b054a4
When adding __builtin_tgmath to support a better tgmath.h
implementation, I noted that further changes might be needed regarding
the TS 18661 functions that round their results to a narrower type,
because of unresolved issues with how the corresponding type-generic
macros are defined in TS 18661.
The resolution of those issues is still in flux, but the latest
version does indeed require something slightly different from
__builtin_tgmath. It specifies that integer arguments to type-generic
macros such as f32xadd are treated as _Float64 not double - which was
also present in earlier versions of the resolution - but then it also
specifies different handling for _Float64 arguments and double
arguments, which wasn't in earlier versions. Specifically, in the
latest version
<http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2213.pdf>, f32xadd
with _Float64 arguments would call f32xaddf64, while f32xadd with
double arguments would call f32xaddf64x. Since integer arguments are
converted directly to the argument type of the selected function (not
to double / _Float64x unless that ends up as the argument type), this
is a user-visible difference in semantics that means __builtin_tgmath
actually needs to implement treating integer arguments as _Float64 in
this case (the rest of the latest semantics can then be implemented in
the header, with a few inline functions there).
To avoid releasing with the older version of the __builtin_tgmath
semantics that doesn't work with the latest proposed DR#13 resolution,
this patch implements a rule in __builtin_tgmath that maps integer
types to _Float64 (respectively _Complex _Float64 for complex integer
types) where all the specified functions return the same _FloatN or
_FloatNx type. This does not affect any existing uses of
__builtin_tgmath in glibc's or GCC's tgmath.h since I haven't yet
added any of these type-generic macros to glibc when adding the
corresponding narrowing functions.
Bootstrapped with no regressions on x86_64-pc-linux-gnu.
* doc/extend.texi (__builtin_tgmath): Document when complex
integer types are treated as _Complex _Float64.
gcc/c:
* c-parser.c (c_parser_postfix_expression): For __builtin_tgmath
where all functions return the same _FloatN or _FloatNx type,
treat integer types as _Float64 instead of double.
gcc/testsuite:
* gcc.dg/builtin-tgmath-3.c: New test.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@258751 138bc75d-0d04-0410-961f-82ee72b054a4