[src/trunk]: src/usr.bin/xlint/lint1 lint: fix wrong warning about losing acc...

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

details:   https://anonhg.NetBSD.org/src/rev/b3281e4c3084
branches:  trunk
changeset: 961035:b3281e4c3084
user:      rillig <rillig%NetBSD.org@localhost>
date:      Tue Apr 06 21:17:27 2021 +0000

description:
lint: fix wrong warning about losing accuracy when converting to _Bool

diffstat:

 tests/usr.bin/xlint/lint1/msg_132.c   |  9 +++++++--
 tests/usr.bin/xlint/lint1/msg_132.exp |  1 -
 usr.bin/xlint/lint1/tree.c            |  7 +++++--
 3 files changed, 12 insertions(+), 5 deletions(-)

diffs (61 lines):

diff -r 5cf6825a5441 -r b3281e4c3084 tests/usr.bin/xlint/lint1/msg_132.c
--- a/tests/usr.bin/xlint/lint1/msg_132.c       Tue Apr 06 21:13:04 2021 +0000
+++ b/tests/usr.bin/xlint/lint1/msg_132.c       Tue Apr 06 21:17:27 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: msg_132.c,v 1.4 2021/04/06 21:10:37 rillig Exp $       */
+/*     $NetBSD: msg_132.c,v 1.5 2021/04/06 21:17:28 rillig Exp $       */
 # 3 "msg_132.c"
 
 // Test for message: conversion from '%s' to '%s' may lose accuracy [132]
@@ -63,9 +63,14 @@
        v64 = v32;
 }
 
+/*
+ * Before tree.c 1.268 from 2021-04-06, lint wrongly warned that conversion to
+ * _Bool might lose accuracy.  C99 6.3.1.2 defines a special conversion rule
+ * from scalar to _Bool though.
+ */
 _Bool
 to_bool(long a, long b)
 {
        /* seen in fp_lib.h, function wideRightShiftWithSticky */
-       return a | b;           /* expect: 132 *//*FIXME*/
+       return a | b;
 }
diff -r 5cf6825a5441 -r b3281e4c3084 tests/usr.bin/xlint/lint1/msg_132.exp
--- a/tests/usr.bin/xlint/lint1/msg_132.exp     Tue Apr 06 21:13:04 2021 +0000
+++ b/tests/usr.bin/xlint/lint1/msg_132.exp     Tue Apr 06 21:17:27 2021 +0000
@@ -10,4 +10,3 @@
 msg_132.c(54): warning: conversion from 'int' to 'short' may lose accuracy [132]
 msg_132.c(55): warning: conversion from 'long long' to 'short' may lose accuracy [132]
 msg_132.c(59): warning: conversion from 'long long' to 'int' may lose accuracy [132]
-msg_132.c(70): warning: conversion from 'long' to '_Bool' may lose accuracy [132]
diff -r 5cf6825a5441 -r b3281e4c3084 usr.bin/xlint/lint1/tree.c
--- a/usr.bin/xlint/lint1/tree.c        Tue Apr 06 21:13:04 2021 +0000
+++ b/usr.bin/xlint/lint1/tree.c        Tue Apr 06 21:17:27 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: tree.c,v 1.267 2021/04/06 13:17:04 rillig Exp $        */
+/*     $NetBSD: tree.c,v 1.268 2021/04/06 21:17:27 rillig Exp $        */
 
 /*
  * Copyright (c) 1994, 1995 Jochen Pohl
@@ -37,7 +37,7 @@
 
 #include <sys/cdefs.h>
 #if defined(__RCSID) && !defined(lint)
-__RCSID("$NetBSD: tree.c,v 1.267 2021/04/06 13:17:04 rillig Exp $");
+__RCSID("$NetBSD: tree.c,v 1.268 2021/04/06 21:17:27 rillig Exp $");
 #endif
 
 #include <float.h>
@@ -1948,6 +1948,9 @@
        if (op == CVT)
                return;
 
+       if (Sflag && nt == BOOL)
+               return;         /* See C99 6.3.1.2 */
+
        if (Pflag && portable_size_in_bits(nt) > portable_size_in_bits(ot) &&
            is_uinteger(nt) != is_uinteger(ot)) {
                if (aflag > 0 && pflag) {