Re: Unaligned access trade-offs for SFrame FRE layout
Segher Boessenkool <[email protected]> Mon, 15 Sep 2025 04:08:29 -0500
| Newsgroups | org.kernel.vger.linux-toolchains |
|---|---|
| Message-ID | <aMfXjVw2ijr7u-Al@gate> |
On 14.09.2025 16:39, Rainer Orth wrote: >> On 12.09.2025 19:34, Indu Bhagat via Binutils wrote: > look for STRICT_ALIGNMENT in the GCC sources in gcc/config. While > several are embedded targets, there's also sparc in that list. > > But is this setting a good reference for the purpose here. It is not a setting usually, also not for you, it is a command-line option. Often it is good (for performance) to only do naturally aligned accesses. For some (sub-)archs it simply is impossible to even try to do misaligned accesses OTOH. > It's okay for gcc to make assumptions (assuming they're properly > documented), Only some implementation decisions have to be documented. And assumptions are almost never okay. Typically we depend on the user promising they do not do X (via a -mno-X flag, say) before we assume they do not do X. Segher