[Bug c++/66573] Unexpected change in static, branch-prediction cost from O1 to O2.

[jmcguiness at liquidcapital dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66573

--- Comment #1 from Jason McG <jmcguiness at liquidcapital dot com> ---
Note that clang++ for all tested versions (3.0, 3.2, 3.3, 3.4.1, 3.5, 3.5.1,
3.6 (rc2), 3.7 (experimental)) produce the same assembler output for -O1, -O2 &
-O3:

foo(bool):                                # @foo(bool)
        testb   %dil, %dil
        je      .LBB0_2
        jmp     bar1()                # TAILCALL
.LBB0_2:
        jmp     bar2()                # TAILCALL

With bar1() being the statically-predicted branch, as per icc and Intel's own
documentation (as referenced in the link in the initial comment).