math: remove redundant infinity tests

These cases are covered by existing comparisons against constants.

Change-Id: I19ad530e95d2437a8617f5229495da591ceb779a
Reviewed-on: https://go-review.googlesource.com/c/go/+/692255
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Sean Liao <sean@liao.dev>
Reviewed-by: Russ Cox <rsc@golang.org>
Auto-Submit: Sean Liao <sean@liao.dev>

diff --git a/src/math/exp.go b/src/math/exp.go
index 050e0ee9d88239988c36d20fc043820c627a5bac..029a4f8163698fe694c8c9375ae189d80cb31671 100644 (file)
--- a/src/math/exp.go
+++ b/src/math/exp.go
@@ -109,13 +109,11 @@ func exp(x float64) float64 {
 
        // special cases
        switch {
-       case IsNaN(x) || IsInf(x, 1):
+       case IsNaN(x):
                return x
-       case IsInf(x, -1):
-               return 0
-       case x > Overflow:
+       case x > Overflow: // handles case where x is +∞
                return Inf(1)
-       case x < Underflow:
+       case x < Underflow: // handles case where x is -∞
                return 0
        case -NearZero < x && x < NearZero:
                return 1 + x
@@ -157,13 +155,11 @@ func exp2(x float64) float64 {
 
        // special cases
        switch {
-       case IsNaN(x) || IsInf(x, 1):
+       case IsNaN(x):
                return x
-       case IsInf(x, -1):
-               return 0
-       case x > Overflow:
+       case x > Overflow: // handles case where x is +∞
                return Inf(1)
-       case x < Underflow:
+       case x < Underflow: // handles case where x is -∞
                return 0
        }