[SR-13837] Swift Decimal type crashes on a specific double value

[swift-ci]

Previous ID	SR-13837
Radar	rdar://problem/71197338
Original Reporter	mohsena (JIRA User)
Type	Bug
Status	Resolved
Resolution	Done

Additional Detail from JIRA

Votes	0
Component/s	Foundation
Labels	Bug
Assignee	None
Priority	Medium

md5: 55011e39127ea36a3fecf9509d128bc7

Issue Description:

(lldb) expr Decimal(1.9446744073709552E19)
(Decimal) $R26 = 19446744073709551616.000000

(lldb) expr Decimal(1.8446744073709552E19)
error: Execution was interrupted, reason: EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0).
The process has been returned to the state before expression evaluation.

(lldb) expr Decimal(2.8446744073709552E19)
(Decimal) $R28 = 28446744073709551616.000000

The value above in bold crashes Swift 1.8446744073709552E19

All other values are fine, even if I simply replace last 2E+19 with 0E+19

[typesanitizer]

@swift-ci create

[swift-ci]

Comment by Glenn Olsson (JIRA)

It is not true that it is fine for all other values. I tried with a few similar numbers and some failed while some did indeed not. For instance:

1.8446744073709550E19 - OK
1.8446744073709551E19 - Fails
1.8446744073709552E19 - Fails (same as mentioned in bug report)
1.8446744073709553E19 - Fails
1.8446744073709554E19 - OK
1.8446744073709555E19 - OK

1.8446744073709550E18 - OK
1.8446744073709551E18 - OK
1.8446744073709552E18 - Fails
1.8446744073709553E18 - Fails
1.8446744073709554E18 - OK
1.8446744073709555E18 - OK

1.8446744073709550E20 - Fails
1.8446744073709551E20 - Fails
1.8446744073709552E20 - Fails
1.8446744073709553E20 - Fails
1.8446744073709554E20 - OK
1.8446744073709555E20 - OK

It is apparent that it really does not depend on the exponent nor the final digit (the only things I checked). It also seem to fail each time to run it, it is not random. It really depends on the number

[spevans]

#2926

[xwu]

For the overlay (i.e., macOS, etc.):
#3056

[FreaksOnE]

I'm still having this issue

Swift version 5.9.2 (swift-5.9.2-RELEASE)
Target: x86_64-unknown-linux-gnu

let x = Decimal(string: "0.000323730024699578384923825161654754178742")!
let y = Decimal(string: "0.000340281878241659205929686457001887171685")!
let result = x / y // crash

[FreaksOnE]

@xwu @shahmishal