Displaying 3 results from an estimated 3 matches for "dcqdvv".
2020 Feb 03
2
Questions about jump threading optimization and what we can do
I am not convinced this is a jump-threading issue, but in the domain
of ScalarEvolution. ScEv would need to find out which of the exits are
taken or whether it loops infinitely. One can see that it exits after
10000 iterations, but ScalarEvolution cannot tell:
https://godbolt.org/z/dCqdvv
Michael
Am Mo., 3. Feb. 2020 um 11:56 Uhr schrieb Karl Rehm <klrehm123 at gmail.com>:
>
> Well ideally it'd do the same thing as before (with two if statements). Something like:
> ret i64 4
>
> It's not really about needing to be as good as gcc, it's more that I w...
2020 Feb 03
2
Questions about jump threading optimization and what we can do
...fused then; if ScEv is
having troubles but it still gets optimized away somewhere, what do you
think is doing it?
On Mon, Feb 3, 2020 at 2:16 PM Karl Rehm <klrehm123 at gmail.com> wrote:
> Ah, I see. I think there's something else going on here too, though.
> https://godbolt.org/z/dCqdvv is optimized away but ScEv doesn't know
> whether this loop terminates either.
>
> On Mon, Feb 3, 2020 at 1:36 PM Michael Kruse <llvmdev at meinersbur.de>
> wrote:
>
>> I am not convinced this is a jump-threading issue, but in the domain
>> of ScalarEvolution. S...
2020 Feb 03
2
Questions about jump threading optimization and what we can do
How does the code you would like to have look like? I don't see a
relevant difference compared to gcc:
https://godbolt.org/z/F-oah4
(clang unnecessarily introduces another temporary register, but that
seems unrelated)
Michael
Am So., 2. Feb. 2020 um 18:24 Uhr schrieb Karl Rehm via llvm-dev
<llvm-dev at lists.llvm.org>:
>
> Here's a better example. https://godbolt.org/z/fpTyFS