Module Name:    src
Committed By:   rillig
Date:           Sun Aug 22 21:17:04 UTC 2021

Modified Files:
        src/tests/usr.bin/xlint/lint1: expr_fold.c expr_fold.exp
            expr_fold_strict_bool.c expr_fold_strict_bool.exp
        src/usr.bin/xlint/lint1: tree.c

Log Message:
lint: fix folding of comparisons in constant expressions


To generate a diff of this commit:
cvs rdiff -u -r1.3 -r1.4 src/tests/usr.bin/xlint/lint1/expr_fold.c \
    src/tests/usr.bin/xlint/lint1/expr_fold.exp
cvs rdiff -u -r1.1 -r1.2 \
    src/tests/usr.bin/xlint/lint1/expr_fold_strict_bool.c \
    src/tests/usr.bin/xlint/lint1/expr_fold_strict_bool.exp
cvs rdiff -u -r1.344 -r1.345 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/expr_fold.c
diff -u src/tests/usr.bin/xlint/lint1/expr_fold.c:1.3 src/tests/usr.bin/xlint/lint1/expr_fold.c:1.4
--- src/tests/usr.bin/xlint/lint1/expr_fold.c:1.3	Sun Aug 22 20:14:24 2021
+++ src/tests/usr.bin/xlint/lint1/expr_fold.c	Sun Aug 22 21:17:04 2021
@@ -1,4 +1,4 @@
-/*	$NetBSD: expr_fold.c,v 1.3 2021/08/22 20:14:24 rillig Exp $	*/
+/*	$NetBSD: expr_fold.c,v 1.4 2021/08/22 21:17:04 rillig Exp $	*/
 # 3 "expr_fold.c"
 
 /*
@@ -292,6 +292,12 @@ fold_bitor(void)
  * expanded to a real monster expression.
  *
  * __CTASSERT(MUL_OK(uint64_t, MAX_N_BLOCKS, MAX_BLOCKSIZE));
+ *
+ * Before tree.c 1.345 from 2021-08-22, lint wrongly assumed that the result
+ * of all binary operators were the common arithmetic type, but that was
+ * wrong for the comparison operators.  The expression '1ULL < 2ULL' does not
+ * have type 'unsigned long long' but 'int' in default mode, or '_Bool' in
+ * strict bool mode.
  */
 struct ctassert5_struct {
 	unsigned int member:
@@ -300,7 +306,5 @@ struct ctassert5_struct {
 	    <=
 		((1ULL << 63) + 1 < 1 ? ~(1ULL << 63) : ~0ULL) / 0xfffffe00U
 		? 1
-		/* FIXME: the above '(1ULL << 63) + 1' is wrong */
-		/* expect+1: error: illegal bit-field size: 255 [36] */
 		: -1;
 };
Index: src/tests/usr.bin/xlint/lint1/expr_fold.exp
diff -u src/tests/usr.bin/xlint/lint1/expr_fold.exp:1.3 src/tests/usr.bin/xlint/lint1/expr_fold.exp:1.4
--- src/tests/usr.bin/xlint/lint1/expr_fold.exp:1.3	Sun Aug 22 20:14:24 2021
+++ src/tests/usr.bin/xlint/lint1/expr_fold.exp	Sun Aug 22 21:17:04 2021
@@ -51,4 +51,3 @@ expr_fold.c(204): warning: integer overf
 expr_fold.c(207): warning: integer overflow detected, op << [141]
 expr_fold.c(211): warning: shift amount 104 is greater than bit-size 32 of 'unsigned int' [122]
 expr_fold.c(223): warning: shift amount 104 is greater than bit-size 32 of 'int' [122]
-expr_fold.c(305): error: illegal bit-field size: 255 [36]

Index: src/tests/usr.bin/xlint/lint1/expr_fold_strict_bool.c
diff -u src/tests/usr.bin/xlint/lint1/expr_fold_strict_bool.c:1.1 src/tests/usr.bin/xlint/lint1/expr_fold_strict_bool.c:1.2
--- src/tests/usr.bin/xlint/lint1/expr_fold_strict_bool.c:1.1	Sun Aug 22 20:56:51 2021
+++ src/tests/usr.bin/xlint/lint1/expr_fold_strict_bool.c	Sun Aug 22 21:17:04 2021
@@ -1,4 +1,4 @@
-/*	$NetBSD: expr_fold_strict_bool.c,v 1.1 2021/08/22 20:56:51 rillig Exp $	*/
+/*	$NetBSD: expr_fold_strict_bool.c,v 1.2 2021/08/22 21:17:04 rillig Exp $	*/
 # 3 "expr_fold_strict_bool.c"
 
 /*
@@ -28,8 +28,14 @@ struct fold_64_bit {
 	/* expect+1: error: illegal bit-field size: 255 [36] */
 	_Bool lt_unsigned_small_bad: 3ULL < 1ULL ? 1 : -1;
 
-	/* FIXME: 1 is much smaller than 1ULL << 63. */
-	/* expect+1: error: illegal bit-field size: 255 [36] */
+	/*
+	 * Before tree.c 1.345 from 2021-08-22, lint wrongly assumed that the
+	 * result of all binary operators were the common arithmetic type,
+	 * but that was wrong for the comparison operators.  The expression
+	 * '1ULL < 2ULL' does not have type 'unsigned long long' but 'int' in
+	 * default mode, or '_Bool' in strict bool mode.
+	 */
 	_Bool lt_unsigned_big_ok: 1ULL < 1ULL << 63 ? 1 : -1;
+	/* expect+1: error: illegal bit-field size: 255 [36] */
 	_Bool lt_unsigned_big_bad: 1ULL << 63 < 1ULL ? 1 : -1;
 };
Index: src/tests/usr.bin/xlint/lint1/expr_fold_strict_bool.exp
diff -u src/tests/usr.bin/xlint/lint1/expr_fold_strict_bool.exp:1.1 src/tests/usr.bin/xlint/lint1/expr_fold_strict_bool.exp:1.2
--- src/tests/usr.bin/xlint/lint1/expr_fold_strict_bool.exp:1.1	Sun Aug 22 20:56:51 2021
+++ src/tests/usr.bin/xlint/lint1/expr_fold_strict_bool.exp	Sun Aug 22 21:17:04 2021
@@ -1,4 +1,4 @@
 expr_fold_strict_bool.c(21): error: illegal bit-field size: 255 [36]
 expr_fold_strict_bool.c(25): error: illegal bit-field size: 255 [36]
 expr_fold_strict_bool.c(29): error: illegal bit-field size: 255 [36]
-expr_fold_strict_bool.c(33): error: illegal bit-field size: 255 [36]
+expr_fold_strict_bool.c(40): error: illegal bit-field size: 255 [36]

Index: src/usr.bin/xlint/lint1/tree.c
diff -u src/usr.bin/xlint/lint1/tree.c:1.344 src/usr.bin/xlint/lint1/tree.c:1.345
--- src/usr.bin/xlint/lint1/tree.c:1.344	Sat Aug 21 11:27:26 2021
+++ src/usr.bin/xlint/lint1/tree.c	Sun Aug 22 21:17:04 2021
@@ -1,4 +1,4 @@
-/*	$NetBSD: tree.c,v 1.344 2021/08/21 11:27:26 rillig Exp $	*/
+/*	$NetBSD: tree.c,v 1.345 2021/08/22 21:17:04 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 1.344 2021/08/21 11:27:26 rillig Exp $");
+__RCSID("$NetBSD: tree.c,v 1.345 2021/08/22 21:17:04 rillig Exp $");
 #endif
 
 #include <float.h>
@@ -3028,9 +3028,10 @@ fold(tnode_t *tn)
 	tnode_t *cn;
 
 	v = xcalloc(1, sizeof(*v));
-	v->v_tspec = t = tn->tn_type->t_tspec;
+	v->v_tspec = tn->tn_type->t_tspec;
 
-	utyp = t == PTR || is_uinteger(t);
+	t = tn->tn_left->tn_type->t_tspec;
+	utyp = !is_integer(t) || is_uinteger(t);
 	ul = sl = tn->tn_left->tn_val->v_quad;
 	if (modtab[tn->tn_op].m_binary)
 		ur = sr = tn->tn_right->tn_val->v_quad;

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