https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127185
--- Comment #3 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Kyrylo Tkachov <[email protected]>: https://gcc.gnu.org/g:dbda2911da5be5e11b7c776893fbc96938acf3ce commit r17-4245-gdbda2911da5be5e11b7c776893fbc96938acf3ce Author: Kyrylo Tkachov <[email protected]> Date: Mon Sep 14 11:56:09 2026 +0200 middle-end: Restore MEM_NOTRAP for memory-only loads [PR127185] EXPAND_MEMORY requires a MEM result but does not state whether the access is a load or a store. Its conservative store semantics avoid unsafe MEM_NOTRAP claims, but two known load callers lose valid nontrapping information. On this patch's parent, a memory-only inline asm input is: (mem/u:SI (...) [ input+0 ]) Restore its load semantics: (mem/u/c:SI (...) [ input+0 ]) The partial-load expander has the same problem. It uses EXPAND_WRITE even though its MEM is the source of a masked or length-limited load. Its source MEM changes from: (mem/u:V4SI (...)) to: (mem/u/c:V4SI (...)) Use EXPAND_MEMORY for partial loads because they require a MEM, then set MEM_NOTRAP from tree_could_trap_p at both caller sites. Bootstrapped and tested on aarch64-unknown-linux-gnu. Tested on x86_64-pc-linux-gnu. PR middle-end/127185 gcc/ChangeLog: * cfgexpand.cc (expand_asm_stmt): Restore load MEM_NOTRAP for memory inputs. * internal-fn.cc: Include tree-eh.h. (expand_partial_load_optab_fn): Expand the source as memory and restore load MEM_NOTRAP. gcc/testsuite/ChangeLog: * g++.dg/opt/mem-notrap-load-asm.C: New test. * gcc.target/i386/mem-notrap-mask-load.c: New test. Signed-off-by: Kyrylo Tkachov <[email protected]>
