Nathan Boley <npbo...@gmail.com> writes: > In a much larger application, I was getting a weird segfault that an > assignment to a temporary variable fixed. I distilled the example into > the attached "test_case.c". When I run test_case.c under valgrind I > get a memory read error, and it segfaults with electric fence, but I'm > not actually able to get a true segfault. However, I am pretty sure > that the same issue was causing the segfault in my application.
There is nothing wrong if gcc is reading an 8-byte value at an 8-byte aligned address. That can not cause a memory read error. To a program like valgrind it may look like a read of an uninitialized memory location, but because the location is aligned and the values loaded from the uninitialized memory is ignored, everything will work fine. That said, I could not recreate the problem with your test case. I only see 4-byte loads. Ian
