Add fast-path for comparing interned (true) string objects.
This patch boosts performance for comparing identical string object
by some 20% on my machine while not causing any noticable slow-down
for other operations (according to tests done with pybench).
diff --git a/Python/ceval.c b/Python/ceval.c
index b707734..34b4cb9 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -1778,6 +1778,21 @@
x = res ? Py_True : Py_False;
Py_INCREF(x);
}
+ else if (v == w && PyString_CheckExact(v)) {
+ /* Fast-path for comparing interned strings */
+ switch (oparg) {
+ case EQ: x = Py_True; break;
+ case LE: x = Py_True; break;
+ case GE: x = Py_True; break;
+ case NE: x = Py_False; break;
+ case GT: x = Py_False; break;
+ case LT: x = Py_False; break;
+ case IS: x = Py_True; break;
+ case IS_NOT: x = Py_False; break;
+ default: goto slow_compare;
+ }
+ Py_INCREF(x);
+ }
else {
slow_compare:
x = cmp_outcome(oparg, v, w);