win32/thread_primitives.hpp: (Unneccessary) Warning

[christian.buss@…]

When compiling with the Intel C++ compiler 12.1, I receive an (unneccessary) warning about an uninitialised variable 'ret':

1>thread_primitives.hpp(356): warning #592: variable "ret" is used before its value is set 1> return ret; 1> ^{1> 1>thread_primitives.hpp(377): warning #592: variable "ret" is used before its value is set 1> return ret; 1>}

Suggested fix: See attached file

[christian.buss@…]

Diff for suggested fix.

[viboes]

In order to avoid the unnecessary assignation for all the compilers I think it is better to apply it conditionally. In addition the current code causing the warning was there for Intel compiler, so the attached patch should work.

[viboes]

Committed in trunk at [80203]

[viboes]

Committed in trunk at [80235]

[viboes]

Merged to release [80450]

[gix]

test-case

[gix]

The warning reported by ICL points at a serious bug. Changesets [80203] and [80235] only silence the warning.

ICL seems to only accept newlines as separator between asm instructions and only emits "mov eax,bit", which makes interlocked_bit_test_and_set return an ret uninitialized.

Running the attached test case:

$ icl -nologo -EHsc boost-7272.cpp && boost-7272.exe
boost-7272.cpp
Testing bit 0 of x=3
result: 0 (expected: 1)
x:      3 (expected: 3)
Testing bit 2 of x=3
result: 0 (expected: 0)
x:      3 (expected: 7)

As a comparison, here with MSVC:

D:\>cl -nologo -EHsc boost-7272.cpp && boost-7272.exe
boost-7272.cpp
Testing bit 0 of x=3
result: 1 (expected: 1)
x:      3 (expected: 3)
Testing bit 2 of x=3
result: 0 (expected: 0)
x:      7 (expected: 7)

Putting each instruction on a separate line (with and without trailing ";") fixes this.

[gix]

Proper patch, reformats asm instructions

[viboes]

Committed in trunk revision [80757].

[viboes]

Merged revision 80955.