Module Name: src
Committed By: rillig
Date: Mon Mar 25 23:39:14 UTC 2024
Modified Files:
src/tests/usr.bin/xlint/lint1: msg_132.c
src/usr.bin/xlint/lint1: tree.c
Log Message:
lint: fix warnings about loss of accuracy on bit-field operations
To generate a diff of this commit:
cvs rdiff -u -r1.37 -r1.38 src/tests/usr.bin/xlint/lint1/msg_132.c
cvs rdiff -u -r1.625 -r1.626 src/usr.bin/xlint/lint1/tree.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/tests/usr.bin/xlint/lint1/msg_132.c
diff -u src/tests/usr.bin/xlint/lint1/msg_132.c:1.37 src/tests/usr.bin/xlint/lint1/msg_132.c:1.38
--- src/tests/usr.bin/xlint/lint1/msg_132.c:1.37 Mon Mar 25 22:46:23 2024
+++ src/tests/usr.bin/xlint/lint1/msg_132.c Mon Mar 25 23:39:14 2024
@@ -1,4 +1,4 @@
-/* $NetBSD: msg_132.c,v 1.37 2024/03/25 22:46:23 rillig Exp $ */
+/* $NetBSD: msg_132.c,v 1.38 2024/03/25 23:39:14 rillig Exp $ */
# 3 "msg_132.c"
// Test for message: conversion from '%s' to '%s' may lose accuracy [132]
@@ -428,19 +428,25 @@ compare_bit_field_to_integer_constant(vo
b = !b;
}
-_Bool
+/*
+ * Before tree.c 1.626 from 2024-03-26, the usual arithmetic conversions for
+ * bit-field types with the same base type but different widths simply took
+ * the type of the left operand, leading to wrong warnings about loss of
+ * accuracy when the right operand was wider than the left operand.
+ */
+void
binary_operators_on_bit_fields(void)
{
struct {
- unsigned long long u15:15;
- unsigned long long u48:48;
- unsigned long long u64;
+ u64_t u15:15;
+ u64_t u48:48;
+ u64_t u64;
} s = { 0, 0, 0 };
u64 = s.u15 | s.u48;
- /* expect+1: warning: conversion from 'unsigned long long:16' to 'int:17' may lose accuracy [132] */
+ u64 = s.u48 | s.u15;
u64 = s.u15 | s.u48 | s.u64;
- /* expect+2: warning: conversion from 'unsigned long long:16' to 'int:17' may lose accuracy [132] */
- /* expect+1: warning: conversion from 'unsigned long long:17' to 'int:18' may lose accuracy [132] */
- return (s.u15 | s.u48 | s.u64) != 0;
+ u64 = s.u64 | s.u48 | s.u15;
+ cond = (s.u15 | s.u48 | s.u64) != 0;
+ cond = (s.u64 | s.u48 | s.u15) != 0;
}
Index: src/usr.bin/xlint/lint1/tree.c
diff -u src/usr.bin/xlint/lint1/tree.c:1.625 src/usr.bin/xlint/lint1/tree.c:1.626
--- src/usr.bin/xlint/lint1/tree.c:1.625 Tue Mar 19 23:19:04 2024
+++ src/usr.bin/xlint/lint1/tree.c Mon Mar 25 23:39:13 2024
@@ -1,4 +1,4 @@
-/* $NetBSD: tree.c,v 1.625 2024/03/19 23:19:04 rillig Exp $ */
+/* $NetBSD: tree.c,v 1.626 2024/03/25 23:39:13 rillig Exp $ */
/*
* Copyright (c) 1994, 1995 Jochen Pohl
@@ -37,7 +37,7 @@
#include <sys/cdefs.h>
#if defined(__RCSID)
-__RCSID("$NetBSD: tree.c,v 1.625 2024/03/19 23:19:04 rillig Exp $");
+__RCSID("$NetBSD: tree.c,v 1.626 2024/03/25 23:39:13 rillig Exp $");
#endif
#include <float.h>
@@ -762,6 +762,13 @@ balance(op_t op, tnode_t **lnp, tnode_t
*lnp = apply_usual_arithmetic_conversions(op, *lnp, t);
if (t != rt)
*rnp = apply_usual_arithmetic_conversions(op, *rnp, t);
+
+ unsigned lw = (*lnp)->tn_type->t_bit_field_width;
+ unsigned rw = (*rnp)->tn_type->t_bit_field_width;
+ if (lw < rw)
+ *lnp = convert(NOOP, 0, (*rnp)->tn_type, *lnp);
+ if (rw < lw)
+ *rnp = convert(NOOP, 0, (*lnp)->tn_type, *rnp);
}
static tnode_t *
