Fix int overflow bug in ‘equal’

Paul Eggert · eggert · commit 1e6396ec3df3 · 2019-06-08T23:38:40.000-07:00
* src/fns.c (internal_equal):
Fix bug when vector lengths exceed INT_MAX.
diff --git a/src/fns.c b/src/fns.c
@@ -2425,7 +2425,6 @@ internal_equal (Lisp_Object o1, Lisp_Object o2, enum equal_kind equal_kind,
 
     case Lisp_Vectorlike:
       {
-	register int i;
 	ptrdiff_t size = ASIZE (o1);
 	/* Pseudovectors have the type encoded in the size field, so this test
 	   actually checks that the objects have the same type as well as the
@@ -2479,7 +2478,7 @@ internal_equal (Lisp_Object o1, Lisp_Object o2, enum equal_kind equal_kind,
 	      return false;
 	    size &= PSEUDOVECTOR_SIZE_MASK;
 	  }
-	for (i = 0; i < size; i++)
+	for (ptrdiff_t i = 0; i < size; i++)
 	  {
 	    Lisp_Object v1, v2;
 	    v1 = AREF (o1, i);

Original file line number	Diff line number	Diff line change
`@@ -2425,7 +2425,6 @@ internal_equal (Lisp_Object o1, Lisp_Object o2, enum equal_kind equal_kind,`
`2425`	`2425`
`2426`	`2426`	`case Lisp_Vectorlike:`
`2427`	`2427`	`{`
`2428`		`- register int i;`
`2429`	`2428`	`ptrdiff_t size = ASIZE (o1);`
`2430`	`2429`	`/* Pseudovectors have the type encoded in the size field, so this test`
`2431`	`2430`	`actually checks that the objects have the same type as well as the`
`@@ -2479,7 +2478,7 @@ internal_equal (Lisp_Object o1, Lisp_Object o2, enum equal_kind equal_kind,`
`2479`	`2478`	`return false;`
`2480`	`2479`	`size &= PSEUDOVECTOR_SIZE_MASK;`
`2481`	`2480`	`}`
`2482`		`- for (i = 0; i < size; i++)`
	`2481`	`+ for (ptrdiff_t i = 0; i < size; i++)`
`2483`	`2482`	`{`
`2484`	`2483`	`Lisp_Object v1, v2;`
`2485`	`2484`	`v1 = AREF (o1, i);`