Re: Remove dependence on integer wrapping

[Nathan Bossart]

I took a closer look at 0002.

+    if (unlikely(isinf(f) || isnan(f)))
+        ereport(ERROR,
+                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+                 errmsg("invalid float value")));
+
+    fresult = rint(f * c);

+    if (unlikely(f == 0.0))
+        ereport(ERROR,
+                (errcode(ERRCODE_DIVISION_BY_ZERO),
+                 errmsg("division by zero")));
+    if (unlikely(isinf(f) || isnan(f)))
+        ereport(ERROR,
+                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+                 errmsg("invalid float value")));
+
+    fresult = rint(c / f);

I'm curious why you aren't using float8_mul/float8_div here, i.e.,

        fresult = rint(float8_mul((float8) c, f));
        fresult = rint(float8_div((float8) c, f));

nitpick: I'd name the functions something like "cash_mul_float8" and
"cash_div_float8".  Perhaps we could also add functions like
"cash_mul_int64" and "cash_sub_int64" so that we don't need several copies
of the same "money out of range" ERROR.

-- 
nathan