diff options
author | Matthew Dempsky <mdempsky@google.com> | 2020-11-24 21:56:47 -0800 |
---|---|---|
committer | Russ Cox <rsc@golang.org> | 2020-11-25 15:47:36 +0000 |
commit | 259fd8adbb15f2a44433c7b8b40a35e97992b345 (patch) | |
tree | e7f2596897f662b68e03902c63dc6f5eb5e53d05 /test/const2.go | |
parent | 18573aea3cc5098c5c27e357e15c507a05de5599 (diff) | |
download | go-259fd8adbb15f2a44433c7b8b40a35e97992b345.tar.gz go-259fd8adbb15f2a44433c7b8b40a35e97992b345.zip |
[dev.regabi] cmd/compile: fix reporting of overflow
In the previous CL, I had incorrectly removed one of the error
messages from issue20232.go, because I thought go/constant was just
handling it. But actually the compiler was panicking in nodlit,
because it didn't handle constant.Unknown. So this CL makes it leave
n.Type == nil for unknown constant.Values.
While here, also address #42732 by making sure to report an error
message when origConst is called with an unknown constant.Value (as
can happen when multiplying two floating-point constants overflows).
Finally, add OXOR and OBITNOT to the list of operations to report
errors about, since they're also constant expressions that can produce
a constant with a greater bit length than their operands.
Fixes #42732.
Change-Id: I4a538fbae9b3ac4c553d7de5625dc0c87d9acce3
Reviewed-on: https://go-review.googlesource.com/c/go/+/272928
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Diffstat (limited to 'test/const2.go')
-rw-r--r-- | test/const2.go | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/test/const2.go b/test/const2.go index 048d0cb9f3..d104a2fa71 100644 --- a/test/const2.go +++ b/test/const2.go @@ -19,3 +19,14 @@ const LargeB = LargeA * LargeA * LargeA const LargeC = LargeB * LargeB * LargeB // GC_ERROR "constant multiplication overflow" const AlsoLargeA = LargeA << 400 << 400 >> 400 >> 400 // GC_ERROR "constant shift overflow" + +// Issue #42732. + +const a = 1e+500000000 +const b = a * a // ERROR "constant multiplication overflow" +const c = b * b + +const MaxInt512 = (1<<256 - 1) * (1<<256 + 1) +const _ = MaxInt512 + 1 // ERROR "constant addition overflow" +const _ = MaxInt512 ^ -1 // ERROR "constant bitwise XOR overflow" +const _ = ^MaxInt512 // ERROR "constant bitwise complement overflow" |