[llvm-dev] x86: How to Force 2-byte `jmp` instruction in lowering

Dean Michael Berris via llvm-dev llvm-dev at lists.llvm.org
Wed Jun 29 17:19:39 PDT 2016

On Thu, Jun 30, 2016 at 3:19 AM Reid Kleckner via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> On Wed, Jun 29, 2016 at 10:05 AM, Craig Topper <craig.topper at gmail.com>
> wrote:
>> I thought jumps start short and relaxation widens them as needed until
>> fixpoint. So relax-all causes them all to be widened unconditionally.
> My mistake, you're right.
> I've been reading that code for years and assuming that it goes
> large-to-small, but I guess the process is the same regardless of which
> direction you go. :)

Okay, so then removing -mrelax-all should make this widening/shortening
work more effectively? i.e. we wouldn't be unconditionally widening short
jumps and allowing the instruction layout process "work as intended"?
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