diff options
author | Russ Cox <rsc@golang.org> | 2014-05-21 17:12:06 -0400 |
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committer | Russ Cox <rsc@golang.org> | 2014-05-21 17:12:06 -0400 |
commit | 563a64b47d6f54188e2301e6b0b26dce599de2b2 (patch) | |
tree | abdef872e232872e24da9f84075fa0935ad0b984 /test/float_lit3.go | |
parent | 0f74caacb45939bc56d228f745852eeb030aa208 (diff) | |
download | go-563a64b47d6f54188e2301e6b0b26dce599de2b2.tar.gz |
test/float_lit2.go: rewrite to test values near boundaries
Add larger comment explaining testing methodology,
and derive tests arithmetically.
(These tests are checking rounding again; the derived
tests they replace were checking exact values.)
LGTM=r, gri
R=gri, r
CC=golang-codereviews
https://codereview.appspot.com/100660044
Diffstat (limited to 'test/float_lit3.go')
-rw-r--r-- | test/float_lit3.go | 52 |
1 files changed, 36 insertions, 16 deletions
diff --git a/test/float_lit3.go b/test/float_lit3.go index f045c40cf..43dca9cfa 100644 --- a/test/float_lit3.go +++ b/test/float_lit3.go @@ -8,21 +8,41 @@ package main +// See float_lit2.go for motivation for these values. +const ( + two24 = 1.0 * (1 << 24) + two53 = 1.0 * (1 << 53) + two64 = 1.0 * (1 << 64) + two128 = two64 * two64 + two256 = two128 * two128 + two512 = two256 * two256 + two768 = two512 * two256 + two1024 = two512 * two512 + + ulp32 = two128 / two24 + max32 = two128 - ulp32 + + ulp64 = two1024 / two53 + max64 = two1024 - ulp64 +) + var x = []interface{}{ - float32(-340282356779733661637539395458142568448), // ERROR "constant -3\.40282e\+38 overflows float32" - float32(-340282356779733661637539395458142568447), - float32(-340282326356119256160033759537265639424), - float32(340282326356119256160033759537265639424), - float32(340282356779733661637539395458142568447), - float32(340282356779733661637539395458142568448), // ERROR "constant 3\.40282e\+38 overflows float32" - -1e1000, // ERROR "constant -1\.00000e\+1000 overflows float64" - float64(-1.797693134862315907937289714053e+308), // ERROR "constant -1\.79769e\+308 overflows float64" - float64(-1.797693134862315807937289714053e+308), - float64(-1.797693134862315708145274237317e+308), - float64(-1.797693134862315608353258760581e+308), - float64(1.797693134862315608353258760581e+308), - float64(1.797693134862315708145274237317e+308), - float64(1.797693134862315807937289714053e+308), - float64(1.797693134862315907937289714053e+308), // ERROR "constant 1\.79769e\+308 overflows float64" - 1e1000, // ERROR "constant 1\.00000e\+1000 overflows float64" + float32(max32 + ulp32/2 - 1), // ok + float32(max32 + ulp32/2 - two128/two256), // ok + float32(max32 + ulp32/2), // ERROR "constant 3\.40282e\+38 overflows float32" + + float32(-max32 - ulp32/2 + 1), // ok + float32(-max32 - ulp32/2 + two128/two256), // ok + float32(-max32 - ulp32/2), // ERROR "constant -3\.40282e\+38 overflows float32" + + // If the compiler's internal floating point representation + // is shorter than 1024 bits, it cannot distinguish max64+ulp64/2-1 and max64+ulp64/2. + // gc uses fewer than 1024 bits, so allow it to print the overflow error for the -1 case. + float64(max64 + ulp64/2 - two1024/two256), // ok + float64(max64 + ulp64/2 - 1), // GC_ERROR "constant 1\.79769e\+308 overflows float64" + float64(max64 + ulp64/2), // ERROR "constant 1\.79769e\+308 overflows float64" + + float64(-max64 - ulp64/2 + two1024/two256), // ok + float64(-max64 - ulp64/2 + 1), // GC_ERROR "constant -1\.79769e\+308 overflows float64" + float64(-max64 - ulp64/2), // ERROR "constant -1\.79769e\+308 overflows float64" } |