strconv: fix round up corner case
Comment described the correct condition
but the code did not implement it.
Fixes #2625.
R=remyoudompheng
CC=golang-dev
https://golang.org/cl/5530082
diff --git a/src/pkg/strconv/ftoa.go b/src/pkg/strconv/ftoa.go
index f4434fd..b1d4b32 100644
--- a/src/pkg/strconv/ftoa.go
+++ b/src/pkg/strconv/ftoa.go
@@ -241,7 +241,7 @@
// Okay to round up if upper has a different digit and
// either upper is inclusive or upper is bigger than the result of rounding up.
- okup := m != u && (inclusive || i+1 < upper.nd)
+ okup := m != u && (inclusive || m+1 < u || i+1 < upper.nd)
// If it's okay to do either, then round to the nearest one.
// If it's okay to do only one, do it.
diff --git a/src/pkg/strconv/ftoa_test.go b/src/pkg/strconv/ftoa_test.go
index 40c71a2..1d90a67 100644
--- a/src/pkg/strconv/ftoa_test.go
+++ b/src/pkg/strconv/ftoa_test.go
@@ -123,6 +123,10 @@
{2.2250738585072012e-308, 'g', -1, "2.2250738585072014e-308"},
// http://www.exploringbinary.com/php-hangs-on-numeric-value-2-2250738585072011e-308/
{2.2250738585072011e-308, 'g', -1, "2.225073858507201e-308"},
+
+ // Issue 2625.
+ {383260575764816448, 'f', 0, "383260575764816448"},
+ {383260575764816448, 'g', -1, "3.8326057576481645e+17"},
}
func TestFtoa(t *testing.T) {
