[src/trunk]: src/usr.bin/xlint/lint1 lint: suppress warnings about LDBL_MAX i...

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/1c0f6cfb7c03
branches:  trunk
changeset: 374244:1c0f6cfb7c03
user:      rillig <rillig%NetBSD.org@localhost>
date:      Wed Apr 12 19:09:48 2023 +0000

description:
lint: suppress warnings about LDBL_MAX in cross-build mode

This fixes the cross build for sparc64 on x86_64, in which lint
complained:
        warning: floating-point constant out of range [248]
        warning: floating point overflow on operator '-' [142]
        warning: floating-point constant out of range [248]

diffstat:

 usr.bin/xlint/lint1/tree.c |  22 +++++++++++++++++++---
 1 files changed, 19 insertions(+), 3 deletions(-)

diffs (43 lines):

diff -r 292b7985b56b -r 1c0f6cfb7c03 usr.bin/xlint/lint1/tree.c
--- a/usr.bin/xlint/lint1/tree.c        Wed Apr 12 17:53:32 2023 +0000
+++ b/usr.bin/xlint/lint1/tree.c        Wed Apr 12 19:09:48 2023 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: tree.c,v 1.511 2023/04/11 19:40:04 rillig Exp $        */
+/*     $NetBSD: tree.c,v 1.512 2023/04/12 19:09:48 rillig Exp $        */
 
 /*
  * Copyright (c) 1994, 1995 Jochen Pohl
@@ -37,7 +37,7 @@
 
 #include <sys/cdefs.h>
 #if defined(__RCSID)
-__RCSID("$NetBSD: tree.c,v 1.511 2023/04/11 19:40:04 rillig Exp $");
+__RCSID("$NetBSD: tree.c,v 1.512 2023/04/12 19:09:48 rillig Exp $");
 #endif
 
 #include <float.h>
@@ -1507,7 +1507,23 @@ floating_error_value(tspec_t t, ldbl_t l
                return lv < 0 ? -FLT_MAX : FLT_MAX;
        if (t == DOUBLE)
                return lv < 0 ? -DBL_MAX : DBL_MAX;
-       return lv < 0 ? -LDBL_MAX : LDBL_MAX;
+       /*
+        * When lint is compiled on x86_64 to check for sparc64, it uses the
+        * type 'long double' from x86_64, which is the Intel 80-bit format.
+        * The constant LDBL_MAX comes from the sparc64 preprocessor though
+        * and uses the IEEE-754-binary128 format, with the same exponent
+        * range but a wider mantissa.
+        *
+        * To properly handle this situation, lint would have to implement the
+        * floating-point types in a platform-independent way, which is not
+        * worth the effort, given how few programs practically use 'long
+        * double'.
+        *
+        * This caveat only affects cross builds.
+        */
+       /* LINTED 248: floating-point constant out of range */
+       ldbl_t max = LDBL_MAX;
+       return lv < 0 ? -max : max;
 }
 
 /*