Comment 6 for bug 1743765

Hi Jamie,

It is very common for new compiler versions to expose bug in projects due to being more aggressive at optimizing based on undefined behavior. Clearly it could also be a bug in the compiler, impossible to know without a full analysis.

To do this, we usually expect a minimal reproducer testcase with a clear explanation of what is going wrong. Ie. we would need a smaller example and an explanation of the form "function foo is not called" or "line X does not seem to be executed" or even better "problem happens in this instruction". As it stands we cannot investigate this issue you are facing.

One way to reduce the testcase would be to compile only one file using the newer toolchain and the other using the old toolchain and see if it still works. If yes, repeat on another file until you have isolated the file that has the bug. Then try to isolate the function (you can split the file into several and put each function in a different file so you can reuse the method I've just described). Once that's done, you can compare the assembly and see if you can spot what's wrong. If not, at least try to make a testcase with just that function, such that we have only a single file to look at. Use -save-temps when compiling that testcase, which will give a .i file with all preprocessing done (ie. we don't need special header to compile that file).

Hope this help.

Best regards.