Issue #7743: Add checks for zero inputs to the lshift and mult functions;
this fixes the first bug described in issue #7743.
diff --git a/Python/dtoa.c b/Python/dtoa.c
index 6e11b9a..6a93aef 100644
--- a/Python/dtoa.c
+++ b/Python/dtoa.c
@@ -622,6 +622,15 @@
ULong z2;
#endif
+ if ((!a->x[0] && a->wds == 1) || (!b->x[0] && b->wds == 1)) {
+ c = Balloc(0);
+ if (c == NULL)
+ return NULL;
+ c->wds = 1;
+ c->x[0] = 0;
+ return c;
+ }
+
if (a->wds < b->wds) {
c = a;
a = b;
@@ -820,6 +829,9 @@
Bigint *b1;
ULong *x, *x1, *xe, z;
+ if (!k || (!b->x[0] && b->wds == 1))
+ return b;
+
n = k >> 5;
k1 = b->k;
n1 = n + b->wds + 1;