code review 5484076: pkg/math: undo manual inlining of IsInf and IsNaN

src/pkg/math/logb.go

 // Copyright 2010 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 package math
 
 // Logb(x) returns the binary exponent of x.
 //
 // Special cases are:
 //      Logb(±Inf) = +Inf
 //      Logb(0) = -Inf
 //      Logb(NaN) = NaN
 func Logb(x float64) float64 {
-        // TODO(rsc): Remove manual inlining of IsNaN, IsInf
-        // when compiler does it for us
         // special cases
         switch {
         case x == 0:
                 return Inf(-1)
-        case x < -MaxFloat64 || x > MaxFloat64: // IsInf(x, 0):
+        case IsInf(x, 0):
                 return Inf(1)
-        case x != x: // IsNaN(x):
+        case IsNaN(x):
                 return x
         }
         return float64(ilogb(x))
 }
 
 // Ilogb(x) returns the binary exponent of x as an integer.
 //
 // Special cases are:
 //      Ilogb(±Inf) = MaxInt32
 //      Ilogb(0) = MinInt32
 //      Ilogb(NaN) = MaxInt32
 func Ilogb(x float64) int {
-        // TODO(rsc): Remove manual inlining of IsNaN, IsInf
-        // when compiler does it for us
         // special cases
         switch {
         case x == 0:
                 return MinInt32
-        case x != x: // IsNaN(x):
+        case IsNaN(x):
                 return MaxInt32
-        case x < -MaxFloat64 || x > MaxFloat64: // IsInf(x, 0):
+        case IsInf(x, 0):
                 return MaxInt32
         }
         return ilogb(x)
 }
 
 // logb returns the binary exponent of x. It assumes x is finite and
 // non-zero.
 func ilogb(x float64) int {
         x, exp := normalize(x)
         return int((Float64bits(x)>>shift)&mask) - bias + exp
 }