Hi, On 2026-02-03 12:24:39 +0700, John Naylor wrote: > On Tue, Feb 3, 2026 at 7:33 AM Andres Freund <[email protected]> wrote: > > It's somewhat scary to see this level of code size increase in a case where > > the compiler really has no information to think vectorizing really is > > beneficial... > > I tried building on gcc 15.2 with -fno-tree-loop-vectorize, and the > server .text segment was only 5kB smaller, but that may understate the > impact on the decisions that get made.
5kB of instructions isn't nothing. But I guess the fact that most of our loops are too complicated might be protecting us :) > Maybe it's better to opt in for unrolling and vectorization? I think I'd go for opting out. There's too many cases where it's going to be hard to see the optimization potential, e.g. due to inlining etc. I do think we probably should add an evolved version of those pragma macros I showed (including perhaps also ones hinting the other way), and use them in the places we manually analyzed... Greetings, Andres Freund
