diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/math/all_test.go | 12 | ||||
| -rw-r--r-- | src/math/pow.go | 15 |
2 files changed, 24 insertions, 3 deletions
diff --git a/src/math/all_test.go b/src/math/all_test.go index 8d5e0ad439..886267bc17 100644 --- a/src/math/all_test.go +++ b/src/math/all_test.go @@ -1687,6 +1687,12 @@ var vfpowSC = [][2]float64{ {Nextafter(1, -2), float64(1 << 63)}, {Nextafter(-1, 2), float64(1 << 63)}, {Nextafter(-1, -2), float64(1 << 63)}, + + // Issue #57465 + {Copysign(0, -1), 1e19}, + {Copysign(0, -1), -1e19}, + {Copysign(0, -1), 1<<53 - 1}, + {Copysign(0, -1), -(1<<53 - 1)}, } var powSC = []float64{ 0, // pow(-Inf, -Pi) @@ -1762,6 +1768,12 @@ var powSC = []float64{ 0, // pow(Nextafter(1, -2), float64(1 << 63)) 0, // pow(Nextafter(-1, 2), float64(1 << 63)) Inf(1), // pow(Nextafter(-1, -2), float64(1 << 63)) + + // Issue #57465 + 0, // pow(-0, 1e19) + Inf(1), // pow(-0, -1e19) + Copysign(0, -1), // pow(-0, 1<<53 -1) + Inf(-1), // pow(-0, -(1<<53 -1)) } var vfpow10SC = []int{ diff --git a/src/math/pow.go b/src/math/pow.go index 3af8c8b649..3f42945376 100644 --- a/src/math/pow.go +++ b/src/math/pow.go @@ -5,6 +5,15 @@ package math func isOddInt(x float64) bool { + if Abs(x) >= (1 << 53) { + // 1 << 53 is the largest exact integer in the float64 format. + // Any number outside this range will be truncated before the decimal point and therefore will always be + // an even integer. + // Without this check and if x overflows int64 the int64(xi) conversion below may produce incorrect results + // on some architectures (and does so on arm64). See issue #57465. + return false + } + xi, xf := Modf(x) return xf == 0 && int64(xi)&1 == 1 } @@ -54,12 +63,12 @@ func pow(x, y float64) float64 { case x == 0: switch { case y < 0: - if isOddInt(y) { - return Copysign(Inf(1), x) + if Signbit(x) && isOddInt(y) { + return Inf(-1) } return Inf(1) case y > 0: - if isOddInt(y) { + if Signbit(x) && isOddInt(y) { return x } return 0 |