On 2025-06-29 05:17, Pádraig Brady wrote:
If we want the compiler to just apply Dead Code Elimination here,
then it may be best to push/pop ignoring that warning ?
Or, since GCC didn't complain about similar code elsewhere, we can
change the complained-about code to look more like the code elsewhere.
This is more likely to pacify any non-GCC compilers that are also flummoxed.
There's a similar situation with the floating point formats, which I
assume you didn't run into because they're all distinct on your platform.
I installed the attached patch which I hope pacifies GCC on your
platform. I didn't observe the problem with gcc (GCC) 15.1.1 20250521
(Red Hat 15.1.1-2) on x86-64 so I can't easily test the patch myself.From dcdb2550c4a6480394fa3b6303a81c7f94461865 Mon Sep 17 00:00:00 2001
From: Paul Eggert <egg...@cs.ucla.edu>
Date: Sun, 29 Jun 2025 17:12:07 -0700
Subject: [PATCH] od: pacify gcc -Wduplicated-cond
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Problem reported by Pádraig Brady <https://bugs.gnu.org/78880#43>.
This patch doesn’t fix any bugs; it merely pacifies GCC.
* src/od.c (ispec_to_format): New function, replacing
the old ISPEC_TO_FORMAT macro. All uses changed.
This part of the change is just refactoring.
(decode_one_format): Pacify à la ispec_to_format.
---
src/od.c | 56 +++++++++++++++++++++++++++++++++++---------------------
1 file changed, 35 insertions(+), 21 deletions(-)
diff --git a/src/od.c b/src/od.c
index 50319aa83..3381ee484 100644
--- a/src/od.c
+++ b/src/od.c
@@ -668,6 +668,21 @@ simple_strtoi (char const *s, char const **p, int *val)
return true;
}
+/* Return a printf format for SPEC, given that remaining arguments are
+ formats for int, long, long long, and intmax_t, respectively. */
+static char const *
+ispec_to_format (enum size_spec size_spec,
+ char const *int_format,
+ char const *long_format,
+ char const *long_long_format,
+ char const *intmax_format)
+{
+ return (LONG < INTMAX && size_spec == INTMAX ? intmax_format
+ : LONG < LONG_LONG && size_spec == LONG_LONG ? long_long_format
+ : INT < LONG && size_spec == LONG ? long_format
+ : int_format);
+}
+
/* If S points to a single valid modern od format string, put
a description of that format in *TSPEC, make *NEXT point at the
character following the just-decoded format (if *NEXT is non-null),
@@ -756,12 +771,6 @@ decode_one_format (char const *s_orig, char const *s, char const **next,
break;
}
-#define ISPEC_TO_FORMAT(Spec, Min_fmt, Long_fmt, Long_long_fmt, Max_fmt) \
- (LONG < INTMAX && (Spec) == INTMAX ? (Max_fmt) \
- : LONG < LONG_LONG && (Spec) == LONG_LONG ? (Long_long_fmt) \
- : INT < LONG && (Spec) == LONG ? (Long_fmt) \
- : (Min_fmt))
-
size_spec = integral_type_size[size];
switch (c)
@@ -770,28 +779,28 @@ decode_one_format (char const *s_orig, char const *s, char const **next,
fmt = SIGNED_DECIMAL;
field_width = INT_BITS_STRLEN_BOUND (CHAR_BIT * size - 1) + 1;
sprintf (tspec->fmt_string, "%%*%s",
- ISPEC_TO_FORMAT (size_spec, "d", "ld", "lld", "jd"));
+ ispec_to_format (size_spec, "d", "ld", "lld", "jd"));
break;
case 'o':
fmt = OCTAL;
field_width = (CHAR_BIT * size + 2) / 3;
sprintf (tspec->fmt_string, "%%*.%d%s", field_width,
- ISPEC_TO_FORMAT (size_spec, "o", "lo", "llo", "jo"));
+ ispec_to_format (size_spec, "o", "lo", "llo", "jo"));
break;
case 'u':
fmt = UNSIGNED_DECIMAL;
field_width = INT_BITS_STRLEN_BOUND (CHAR_BIT * size);
sprintf (tspec->fmt_string, "%%*%s",
- ISPEC_TO_FORMAT (size_spec, "u", "lu", "llu", "ju"));
+ ispec_to_format (size_spec, "u", "lu", "llu", "ju"));
break;
case 'x':
fmt = HEXADECIMAL;
field_width = (CHAR_BIT * size + 3) / 4;
sprintf (tspec->fmt_string, "%%*.%d%s", field_width,
- ISPEC_TO_FORMAT (size_spec, "x", "lx", "llx", "jx"));
+ ispec_to_format (size_spec, "x", "lx", "llx", "jx"));
break;
default:
@@ -801,14 +810,18 @@ decode_one_format (char const *s_orig, char const *s, char const **next,
/* Prefer INT, prefer LONG to longer types,
and prefer INTMAX to LONG_LONG. */
print_function
- = (size_spec == INT ? print_int
- : size_spec == SHORT ? (fmt == SIGNED_DECIMAL
- ? print_s_short : print_short)
- : size_spec == CHAR ? (fmt == SIGNED_DECIMAL
- ? print_s_char : print_char)
- : size_spec == LONG ? print_long
- : size_spec == INTMAX ? print_intmax
- : size_spec == LONG_LONG ? print_long_long
+ = (size_spec == INT
+ ? print_int
+ : SHORT < INT && size_spec == SHORT
+ ? (fmt == SIGNED_DECIMAL ? print_s_short : print_short)
+ : CHAR < SHORT && size_spec == CHAR
+ ? (fmt == SIGNED_DECIMAL ? print_s_char : print_char)
+ : INT < LONG && size_spec == LONG
+ ? print_long
+ : LONG < INTMAX && size_spec == INTMAX
+ ? print_intmax
+ : LONG < LONG_LONG && LONG_LONG < INTMAX && size_spec == LONG_LONG
+ ? print_long_long
: (affirm (false), nullptr));
break;
@@ -892,18 +905,19 @@ decode_one_format (char const *s_orig, char const *s, char const **next,
print_function = print_double;
field_width = DBL_STRLEN_BOUND_L (decimal_point_len);
}
- else if (size_spec == FLOAT_SINGLE)
+ else if (FLOAT_SINGLE < FLOAT_DOUBLE && size_spec == FLOAT_SINGLE)
{
print_function = print_float;
field_width = FLT_STRLEN_BOUND_L (decimal_point_len);
}
- else if (size_spec == FLOAT_HALF)
+ else if (FLOAT_HALF < FLOAT_SINGLE && size_spec == FLOAT_HALF)
{
print_function = fmt == BFLOATING_POINT
? print_bfloat : print_halffloat;
field_width = FLT_STRLEN_BOUND_L (decimal_point_len);
}
- else if (size_spec == FLOAT_LONG_DOUBLE)
+ else if (FLOAT_DOUBLE < FLOAT_LONG_DOUBLE
+ && size_spec == FLOAT_LONG_DOUBLE)
{
print_function = print_long_double;
field_width = LDBL_STRLEN_BOUND_L (decimal_point_len);
--
2.48.1
