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author | Joseph Myers <joseph@codesourcery.com> | 2018-03-21 22:29:37 +0000 |
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committer | Joseph Myers <jsm28@gcc.gnu.org> | 2018-03-21 22:29:37 +0000 |
commit | c5c5822ae5c421e2f22e201366231a502c91b70a (patch) | |
tree | a1c2dc12c2981309138920b82613f39bb26024b4 /gcc/c/c-parser.c | |
parent | f4274af890e1a2938ff4604cee1113f33cdce03e (diff) | |
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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.
From-SVN: r258751
Diffstat (limited to 'gcc/c/c-parser.c')
-rw-r--r-- | gcc/c/c-parser.c | 25 |
1 files changed, 21 insertions, 4 deletions
diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c index 945838c..4772086 100644 --- a/gcc/c/c-parser.c +++ b/gcc/c/c-parser.c @@ -8530,10 +8530,12 @@ c_parser_postfix_expression (c_parser *parser) argument is decimal, or if the only alternatives for type-generic arguments are of decimal types, and are otherwise treated as double (or _Complex double for - complex integer types). After that adjustment, types - are combined following the usual arithmetic - conversions. If the function only accepts complex - arguments, a complex type is produced. */ + complex integer types, or _Float64 or _Complex _Float64 + if all the return types are the same _FloatN or + _FloatNx type). After that adjustment, types are + combined following the usual arithmetic conversions. + If the function only accepts complex arguments, a + complex type is produced. */ bool arg_complex = all_complex; bool arg_binary = all_binary; bool arg_int_decimal = all_decimal; @@ -8632,6 +8634,19 @@ c_parser_postfix_expression (c_parser *parser) } } } + /* For a macro rounding its result to a narrower type, map + integer types to _Float64 not double if the return type + is a _FloatN or _FloatNx type. */ + bool arg_int_float64 = false; + if (parm_kind[0] == tgmath_fixed + && SCALAR_FLOAT_TYPE_P (parm_first[0]) + && float64_type_node != NULL_TREE) + for (unsigned int j = 0; j < NUM_FLOATN_NX_TYPES; j++) + if (parm_first[0] == FLOATN_TYPE_NODE (j)) + { + arg_int_float64 = true; + break; + } tree arg_real = NULL_TREE; for (unsigned int j = 1; j <= nargs; j++) { @@ -8644,6 +8659,8 @@ c_parser_postfix_expression (c_parser *parser) if (INTEGRAL_TYPE_P (type)) type = (arg_int_decimal ? dfloat64_type_node + : arg_int_float64 + ? float64_type_node : double_type_node); if (arg_real == NULL_TREE) arg_real = type; |