Discussion:
[PATCH] ftoastr: port to -Wdouble-promotion
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Paul Eggert
2017-02-24 16:45:21 UTC
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Raw Message
Work around -Wdouble-promotion false alarm in recent GCCs.
* lib/ftoastr.c (PROMOTED_FLOAT): New macro.
(ftoastr_snprintf, FTOASTR): Use it.
---
ChangeLog | 7 +++++++
lib/ftoastr.c | 11 ++++++++---
2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index c36d0de..a6f6b8b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2017-02-24 Paul Eggert <***@cs.ucla.edu>
+
+ ftoastr: port to -Wdouble-promotion
+ Work around -Wdouble-promotion false alarm in recent GCCs.
+ * lib/ftoastr.c (PROMOTED_FLOAT): New macro.
+ (ftoastr_snprintf, FTOASTR): Use it.
+
2017-02-21 Bruno Haible <***@clisp.org>

lock tests: Fix build failure on GNU/Hurd (regression from 2017-01-05).
diff --git a/lib/ftoastr.c b/lib/ftoastr.c
index 826340c..ef861e2 100644
--- a/lib/ftoastr.c
+++ b/lib/ftoastr.c
@@ -39,6 +39,7 @@
# define FLOAT_MIN LDBL_MIN
# define FLOAT_PREC_BOUND _GL_LDBL_PREC_BOUND
# define FTOASTR ldtoastr
+# define PROMOTED_FLOAT long double
# if HAVE_C99_STRTOLD
# define STRTOF strtold
# endif
@@ -48,6 +49,7 @@
# define FLOAT_MIN DBL_MIN
# define FLOAT_PREC_BOUND _GL_DBL_PREC_BOUND
# define FTOASTR dtoastr
+# define PROMOTED_FLOAT double
#else
# define LENGTH 1
# define FLOAT float
@@ -55,6 +57,7 @@
# define FLOAT_MIN FLT_MIN
# define FLOAT_PREC_BOUND _GL_FLT_PREC_BOUND
# define FTOASTR ftoastr
+# define PROMOTED_FLOAT double
# if HAVE_STRTOF
# define STRTOF strtof
# endif
@@ -77,20 +80,21 @@ static int
ftoastr_snprintf (char *buf, size_t bufsize, char const *format,
int width, int prec, FLOAT x)
{
+ PROMOTED_FLOAT promoted_x = x;
char width_0_buffer[LENGTH == 1 ? FLT_BUFSIZE_BOUND
: LENGTH == 2 ? DBL_BUFSIZE_BOUND
: LDBL_BUFSIZE_BOUND];
int n = width;
if (bufsize < sizeof width_0_buffer)
{
- n = sprintf (width_0_buffer, format, 0, prec, x);
+ n = sprintf (width_0_buffer, format, 0, prec, promoted_x);
if (n < 0)
return n;
if (n < width)
n = width;
}
if (n < bufsize)
- n = sprintf (buf, format, width, prec, x);
+ n = sprintf (buf, format, width, prec, promoted_x);
return n;
}
#endif
@@ -106,6 +110,7 @@ FTOASTR (char *buf, size_t bufsize, int flags, int width, FLOAT x)
<http://dx.doi.org/10.1145/1809028.1806623>; also see the
2010-03-21 draft <http://florian.loitsch.com/tmp/article.pdf>. */

+ PROMOTED_FLOAT promoted_x = x;
char format[sizeof "%-+ 0*.*Lg"];
FLOAT abs_x = x < 0 ? -x : x;
int prec;
@@ -128,7 +133,7 @@ FTOASTR (char *buf, size_t bufsize, int flags, int width, FLOAT x)

for (prec = abs_x < FLOAT_MIN ? 1 : FLOAT_DIG; ; prec++)
{
- int n = snprintf (buf, bufsize, format, width, prec, x);
+ int n = snprintf (buf, bufsize, format, width, prec, promoted_x);
if (n < 0
|| FLOAT_PREC_BOUND <= prec
|| (n < bufsize && STRTOF (buf, NULL) == x))
--
2.9.3
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