On Thu, Nov 26, 2020 at 9:21 PM Alex Markin via Gcc-help <gcc-help@xxxxxxxxxxx> wrote: > > Hello. > > I don't know if it is a gcc or binutils problem. I have different results > for `expl' function depending on the argument was variable or literal: > > long double c, r1, r2; > r1 = expl(-1); > > c = -1; > r2 = expl(c); > > In this example r1 and r2 differ in the lower bits. The entire example is > here: https://godbolt.org/z/xqn4bd. The llvm does not have such a problem. The reason is that the Intel-specific 80 bit long double format is used. So the first 80 bits of r1 and r2 contain the value, and the rest remains uninitialized. You could memset both to 0 first, then the comparison would check out. I'm sure there is a good reason for sizeof producing 16, not 10.
