[PATCH 2/6] bitset: possibly widen unsigned indexes

* lib/bitset/vector.c (vbitset_empty_p, vbitset_not)
(vbitset_disjoint_p, vbitset_and, vbitset_and_or)
(vbitset_and_or_cmp, vbitset_andn_or, vbitset_andn_or_cmp)
(vbitset_or_and, vbitset_or_and_cmp):
In a for-loop, use an index type related to the upper bound’s type
rather than trusting ‘unsigned’ to be wide enough.
---
 ChangeLog           |  8 ++++++++
 lib/bitset/vector.c | 20 ++++++++++----------
 2 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index a5282f0450..462d4953c4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
 2026-06-26  Paul Eggert  <[email protected]>
 
+	bitset: possibly widen unsigned indexes
+	* lib/bitset/vector.c (vbitset_empty_p, vbitset_not)
+	(vbitset_disjoint_p, vbitset_and, vbitset_and_or)
+	(vbitset_and_or_cmp, vbitset_andn_or, vbitset_andn_or_cmp)
+	(vbitset_or_and, vbitset_or_and_cmp):
+	In a for-loop, use an index type related to the upper bound’s type
+	rather than trusting ‘unsigned’ to be wide enough.
+
 	bitrotate: prefer C2y to bitrotate or by-hand
 	Deprecate the bitrotate module; it is superseded by C2y’s
 	stdc_rotate_left and stdc_rotate_right.  In several places, prefer
diff --git a/lib/bitset/vector.c b/lib/bitset/vector.c
index 11c8a411a8..5140ab9b30 100644
--- a/lib/bitset/vector.c
+++ b/lib/bitset/vector.c
@@ -320,7 +320,7 @@ vbitset_empty_p (bitset dst)
 {
   bitset_word *dstp = VBITSET_WORDS (dst);
 
-  for (unsigned i = 0; i < VBITSET_SIZE (dst); i++)
+  for (bitset_windex i = 0; i < VBITSET_SIZE (dst); i++)
     if (dstp[i])
       return false;
   return true;
@@ -357,7 +357,7 @@ vbitset_not (bitset dst, bitset src)
   bitset_windex ssize = VBITSET_SIZE (src);
   bitset_windex dsize = VBITSET_SIZE (dst);
 
-  for (unsigned i = 0; i < ssize; i++)
+  for (bitset_windex i = 0; i < ssize; i++)
     *dstp++ = ~(*srcp++);
 
   vbitset_unused_clear (dst);
@@ -426,7 +426,7 @@ vbitset_disjoint_p (bitset dst, bitset src)
   bitset_windex ssize = VBITSET_SIZE (src);
   bitset_windex dsize = VBITSET_SIZE (dst);
 
-  for (unsigned i = 0; i < min (ssize, dsize); i++)
+  for (bitset_windex i = 0; i < min (ssize, dsize); i++)
     if (*srcp++ & *dstp++)
       return false;
 
@@ -446,7 +446,7 @@ vbitset_and (bitset dst, bitset src1, bitset src2)
   bitset_word *src1p = VBITSET_WORDS (src1);
   bitset_word *src2p = VBITSET_WORDS (src2);
 
-  for (unsigned i = 0; i < min (ssize1, ssize2); i++)
+  for (bitset_windex i = 0; i < min (ssize1, ssize2); i++)
     *dstp++ = *src1p++ & *src2p++;
 
   memset (dstp, 0, sizeof (bitset_word) * (dsize - min (ssize1, ssize2)));
@@ -765,7 +765,7 @@ vbitset_and_or (bitset dst, bitset src1, bitset src2, bitset src3)
   bitset_word *dstp = VBITSET_WORDS (dst);
   bitset_windex size = VBITSET_SIZE (dst);
 
-  for (unsigned i = 0; i < size; i++)
+  for (bitset_windex i = 0; i < size; i++)
     *dstp++ = (*src1p++ & *src2p++) | *src3p++;
 }
 
@@ -786,7 +786,7 @@ vbitset_and_or_cmp (bitset dst, bitset src1, bitset src2, bitset src3)
   bitset_windex size = VBITSET_SIZE (dst);
 
   bool changed = false;
-  for (unsigned i = 0; i < size; i++, dstp++)
+  for (bitset_windex i = 0; i < size; i++, dstp++)
     {
       bitset_word tmp = (*src1p++ & *src2p++) | *src3p++;
 
@@ -818,7 +818,7 @@ vbitset_andn_or (bitset dst, bitset src1, bitset src2, bitset src3)
   bitset_word *dstp = VBITSET_WORDS (dst);
   bitset_windex size = VBITSET_SIZE (dst);
 
-  for (unsigned i = 0; i < size; i++)
+  for (bitset_windex i = 0; i < size; i++)
     *dstp++ = (*src1p++ & ~(*src2p++)) | *src3p++;
 }
 
@@ -839,7 +839,7 @@ vbitset_andn_or_cmp (bitset dst, bitset src1, bitset src2, bitset src3)
   bitset_windex size = VBITSET_SIZE (dst);
 
   bool changed = false;
-  for (unsigned i = 0; i < size; i++, dstp++)
+  for (bitset_windex i = 0; i < size; i++, dstp++)
     {
       bitset_word tmp = (*src1p++ & ~(*src2p++)) | *src3p++;
 
@@ -871,7 +871,7 @@ vbitset_or_and (bitset dst, bitset src1, bitset src2, bitset src3)
   bitset_word *dstp = VBITSET_WORDS (dst);
   bitset_windex size = VBITSET_SIZE (dst);
 
-  for (unsigned i = 0; i < size; i++)
+  for (bitset_windex i = 0; i < size; i++)
     *dstp++ = (*src1p++ | *src2p++) & *src3p++;
 }
 
@@ -892,7 +892,7 @@ vbitset_or_and_cmp (bitset dst, bitset src1, bitset src2, bitset src3)
   bitset_windex size = VBITSET_SIZE (dst);
 
   bool changed = false;
-  for (unsigned int i = 0; i < size; i++)
+  for (bitset_windex i = 0; i < size; i++)
     {
       bitset_word tmp = (*src1p++ | *src2p++) & *src3p++;
 
-- 
2.54.0