Float128(Float64(pi)) crashes REPL

[JeffreySarnoff]

Float128( x ) where x is a Float64 makes the REPL go away.
Float80( x ) does not have that issue.

[rfourquet]

Is there any error message by any chance, like from LLVM?

[JeffreySarnoff]

(lines scroll very fast and then the REPL window closes itself), redirecting the output I get

julia -e"using BitFloats; a=0.5; b=Float128(a);" >> out.txt
on Julia 1.4.1

Please submit a bug report with steps to reproduce this fault, and any error messages that follow (in their entirety). Thanks.
Exception: EXCEPTION_ACCESS_VIOLATION at 0x6144be3c -- _extenddftf2 at C:\Users\jas\AppData\Local\Programs\Julia\Julia-1.4.0\bin\libgcc_s_seh-1.dll (unknown line)
in expression starting at none:1
_extenddftf2 at C:\Users\jas\AppData\Local\Programs\Julia\Julia-1.4.0\bin\libgcc_s_seh-1.dll (unknown line)
Float128 at C:\Users\jas\.julia\packages\BitFloats\qTO7E\src\BitFloats.jl:336
unknown function (ip: 000000001D9B7274)
jl_apply at /cygdrive/d/buildbot/worker/package_win64/build/src\julia.h:1700 [inlined]
do_call at /cygdrive/d/buildbot/worker/package_win64/build/src\interpreter.c:369
eval_value at /cygdrive/d/buildbot/worker/package_win64/build/src\interpreter.c:458
eval_stmt_value at /cygdrive/d/buildbot/worker/package_win64/build/src\interpreter.c:409 [inlined]
eval_body at /cygdrive/d/buildbot/worker/package_win64/build/src\interpreter.c:799
jl_interpret_toplevel_thunk at /cygdrive/d/buildbot/worker/package_win64/build/src\interpreter.c:911
jl_toplevel_eval_flex at /cygdrive/d/buildbot/worker/package_win64/build/src\toplevel.c:814
jl_toplevel_eval_flex at /cygdrive/d/buildbot/worker/package_win64/build/src\toplevel.c:764
jl_toplevel_eval_flex at /cygdrive/d/buildbot/worker/package_win64/build/src\toplevel.c:764
jl_toplevel_eval at /cygdrive/d/buildbot/worker/package_win64/build/src\toplevel.c:823 [inlined]
jl_toplevel_eval_in at /cygdrive/d/buildbot/worker/package_win64/build/src\toplevel.c:843
eval at .\boot.jl:331
exec_options at .\client.jl:264
_start at .\client.jl:484
jfptr__start_2087.clone_1 at C:\Users\jas\AppData\Local\Programs\Julia\Julia-1.4.0\lib\julia\sys.dll (unknown line)
unknown function (ip: 00000000004017E1)
unknown function (ip: 0000000000401BD6)
unknown function (ip: 00000000004013DE)
unknown function (ip: 000000000040151A)
BaseThreadInitThunk at C:\WINDOWS\System32\KERNEL32.DLL (unknown line)
RtlUserThreadStart at C:\WINDOWS\SYSTEM32\ntdll.dll (unknown line)
Allocations: 807581 (Pool: 807371; Big: 210); GC: 1

and again on Julia v1.6-DEV

Please submit a bug report with steps to reproduce this fault, and any error messages that follow (in their entirety). Thanks.
Exception: EXCEPTION_ACCESS_VIOLATION at 0x6144a625 -- _unordtf2 at C:\Users\jas\AppData\Local\Programs\Julia 1.6.0\bin\libgcc_s_seh-1.dll (unknown line)
in expression starting at none:0
_unordtf2 at C:\Users\jas\AppData\Local\Programs\Julia 1.6.0\bin\libgcc_s_seh-1.dll (unknown line)
!= at C:\Users\jas\.julia\packages\BitFloats\qTO7E\src\BitFloats.jl:527 [inlined]
isnan at .\float.jl:536 [inlined]
show at C:\Users\jas\.julia\packages\BitFloats\qTO7E\src\BitFloats.jl:654
show at .\multimedia.jl:47
unknown function (ip: 000000001DEBCACB)
display at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\REPL\src\REPL.jl:214
display at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\REPL\src\REPL.jl:218
display at .\multimedia.jl:328
jl_apply at /cygdrive/d/buildbot/worker/package_win64/build/src\julia.h:1701 [inlined]
do_apply at /cygdrive/d/buildbot/worker/package_win64/build/src\builtins.c:655
jl_f__apply at /cygdrive/d/buildbot/worker/package_win64/build/src\builtins.c:669 [inlined]
jl_f__apply_latest at /cygdrive/d/buildbot/worker/package_win64/build/src\builtins.c:705
#invokelatest#1 at .\essentials.jl:710 [inlined]
invokelatest at .\essentials.jl:709 [inlined]
print_response at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\REPL\src\REPL.jl:238
print_response at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\REPL\src\REPL.jl:223
do_respond at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\REPL\src\REPL.jl:822
jfptr_do_respond_63642.clone_1 at C:\Users\jas\AppData\Local\Programs\Julia 1.6.0\lib\julia\sys.dll (unknown line)
jl_apply at /cygdrive/d/buildbot/worker/package_win64/build/src\julia.h:1701 [inlined]
do_apply at /cygdrive/d/buildbot/worker/package_win64/build/src\builtins.c:655
jl_f__apply at /cygdrive/d/buildbot/worker/package_win64/build/src\builtins.c:669 [inlined]
jl_f__apply_latest at /cygdrive/d/buildbot/worker/package_win64/build/src\builtins.c:705
#invokelatest#1 at .\essentials.jl:710 [inlined]
invokelatest at .\essentials.jl:709 [inlined]
run_interface at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\REPL\src\LineEdit.jl:2354
jfptr_run_interface_62006.clone_1 at C:\Users\jas\AppData\Local\Programs\Julia 1.6.0\lib\julia\sys.dll (unknown line)
run_frontend at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.6\REPL\src\REPL.jl:1143
#38 at .\task.jl:358
unknown function (ip: 000000001DEB20D3)
jl_apply at /cygdrive/d/buildbot/worker/package_win64/build/src\julia.h:1701 [inlined]
start_task at /cygdrive/d/buildbot/worker/package_win64/build/src\task.c:707
Allocations: 6845464 (Pool: 6844410; Big: 1054); GC: 9

[JeffreySarnoff]

I entered an issue with julia on github.

[JeffreySarnoff]

from Yichao's informative comment JuliaLang/julia#36528 (comment) f

Actually according to clang __float128 is just not supported on win64. And LLVM is not even trying to match the GCC ABI of __extenddftf2 and is actually passing everything in registers. Either clang+llvm should be fixed to support __float128 or BitFloats needs to manually call the correct function. The latter is what https://github.com/JuliaMath/Quadmath.jl/blob/master/src/Quadmath.jl#L129 is doing.
I don't think there's anything to be done in julia for this issue...