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lint: fix excessive overflow warning after division by zero

This commit is contained in:
rillig 2024-03-09 23:55:11 +00:00
parent 76021c6ba1
commit 3e856647d2
2 changed files with 9 additions and 11 deletions
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6
tests/usr.bin/xlint/lint1/expr_fold.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: expr_fold.c,v 1.11 2024/01/06 15:05:24 rillig Exp $ */
/* $NetBSD: expr_fold.c,v 1.12 2024/03/09 23:55:11 rillig Exp $ */
# 3 "expr_fold.c"
/*
@ -114,9 +114,7 @@ fold_mult(void)
void
fold_div(void)
{
/* expect+3: error: division by 0 [139] */
/* XXX: The following message is redundant. */
/* expect+1: warning: operator '/' produces integer overflow [141] */
/* expect+1: error: division by 0 [139] */
take_int(0 / 0);
/* expect+1: warning: conversion of 'long' to 'int' is out of range, arg #1 [295] */

14
usr.bin/xlint/lint1/tree.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: tree.c,v 1.613 2024/03/09 14:54:14 rillig Exp $ */
/* $NetBSD: tree.c,v 1.614 2024/03/09 23:55:11 rillig Exp $ */
/*
* Copyright (c) 1994, 1995 Jochen Pohl
@ -37,7 +37,7 @@
#include <sys/cdefs.h>
#if defined(__RCSID)
__RCSID("$NetBSD: tree.c,v 1.613 2024/03/09 14:54:14 rillig Exp $");
__RCSID("$NetBSD: tree.c,v 1.614 2024/03/09 23:55:11 rillig Exp $");
#endif
#include <float.h>
@ -809,6 +809,8 @@ fold_constant_integer(tnode_t *tn)
ur = sr = tn->u.ops.right->u.value.u.integer;
uint64_t mask = value_bits(size_in_bits(t));
int64_t max_value = (int64_t)(mask >> 1);
int64_t min_value = -max_value - 1;
bool ovfl = false;
int64_t si;
@ -841,11 +843,9 @@ fold_constant_integer(tnode_t *tn)
if (sr == 0) {
/* division by 0 */
error(139);
si = utyp ? -1 : INT64_MAX;
} else if (!utyp
&& (sl & mask) == (mask ^ (mask >> 1)) && sr == -1) {
/* operator '%s' produces integer overflow */
warning(141, op_name(DIV));
si = utyp ? -1 : max_value;
} else if (!utyp && sl == min_value && sr == -1) {
ovfl = true;
si = sl;
} else
si = utyp ? (int64_t)(ul / ur) : sl / sr;