Strange issues with bit operations

[schmee]

I've run in to a strange issue in a project I've been working on. Basically, this line causes a change of behavior in --release-safe and --release-fast modes. Here's what it looks like running the tests:

With the line uncommented, the tests pass in debug, release-safe and release-fast:

➜  test git:(master) zig test des_test.zig
Test 1/7 test vectors ECB encrypt...OK
Test 2/7 test vectors ECB decrypt...OK
Test 3/7 encrypt random data with ECB...OK
Test 4/7 decrypt random data with ECB...OK
Test 5/7 3DES ECB crypt...OK
Test 6/7 DES CBC crypt...OK
Test 7/7 3DES CBC crypt...OK
All tests passed.

With the line commented, the follow happens:

• debug - tests pass

➜  test git:(master) ✗ zig test des_test.zig
Test 1/7 test vectors ECB encrypt...OK
Test 2/7 test vectors ECB decrypt...OK
Test 3/7 encrypt random data with ECB...OK
Test 4/7 decrypt random data with ECB...OK
Test 5/7 3DES ECB crypt...OK
Test 6/7 DES CBC crypt...OK
Test 7/7 3DES CBC crypt...OK
All tests passed.

• --release-safe - tests fail because they produce incorrect output, but no crash:

➜  test git:(master) ✗ zig test --release-safe des_test.zig
Test 1/7 test vectors ECB encrypt...expected 10137153925907983143, found 10784105874870413645

Tests failed. Use the following command to reproduce the failure:
/Users/john.schmidt/personal_programming/zig/des/test/zig-cache/test

• --release-fast - the compiler hangs

➜  test git:(master) ✗ zig test --release-fast des_test.zig
(nothing happens)

All of these issues might be a symptom of #1932, but since I'm not sure I thought I'd open a separate issue to track it somewhere.

Versions:

➜  des git:(master) zig version
0.3.0+c58b8020

macOS Mojave 10.14.3

[schmee]

Closing this in favor of #3980 since it's the same issue with a better repro.