Arithmetic overflows now return float rather than wrapping around.

* data.c: Include <intprops.h>.
(arith_driver): Use floating point if the accumulator would otherwise
go out of EMACS_INT range.
(arith_driver, Fadd1, Fsub1): Use floating point if the result is
out of Emacs fixnum range.
* bytecode.c (exec_byte_code): Likewise, for Bsub1, Badd1, Bnegate.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/bytecode.c b/src/bytecode.c
index c3cd3d43072..ce79b011bbb 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -1186,7 +1186,7 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
           {
             Lisp_Object v1;
             v1 = TOP;
-            if (INTEGERP (v1))
+            if (INTEGERP (v1) && MOST_NEGATIVE_FIXNUM < XINT (v1))
               {
                 XSETINT (v1, XINT (v1) - 1);
                 TOP = v1;
@@ -1204,7 +1204,7 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
           {
             Lisp_Object v1;
             v1 = TOP;
-            if (INTEGERP (v1))
+            if (INTEGERP (v1) && XINT (v1) < MOST_POSITIVE_FIXNUM)
               {
                 XSETINT (v1, XINT (v1) + 1);
                 TOP = v1;
@@ -1290,7 +1290,7 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
           {
             Lisp_Object v1;
             v1 = TOP;
-            if (INTEGERP (v1))
+            if (INTEGERP (v1) && - MOST_POSITIVE_FIXNUM <= XINT (v1))
               {
                 XSETINT (v1, - XINT (v1));
                 TOP = v1;