numeric.c: optimize `float ** 2` case by fastpath

It would be a relatively frequent case.  It is still slower than
`float * float` because `*` has a dedicated VM instruction (opt_mult),
though.

1 files changed, 5 insertions, 1 deletions

diff --git a/numeric.c b/numeric.c
index 03d8b86a1d..04fd3a24af 100644
--- a/numeric.c
+++ b/numeric.c
@@ -1309,7 +1309,11 @@ VALUE
 rb_float_pow(VALUE x, VALUE y)
 {
     double dx, dy;
-    if (RB_TYPE_P(y, T_FIXNUM)) {
+    if (y == INT2FIX(2)) {
+	dx = RFLOAT_VALUE(x);
+        return DBL2NUM(dx * dx);
+    }
+    else if (RB_TYPE_P(y, T_FIXNUM)) {
 	dx = RFLOAT_VALUE(x);
 	dy = (double)FIX2LONG(y);
     }