https://gcc.gnu.org/g:8775c986904b3b796dbf292dd8a6d5a1486f1b9c
commit r13-10130-g8775c986904b3b796dbf292dd8a6d5a1486f1b9c Author: Andrew Pinski <[email protected]> Date: Tue Sep 2 13:57:26 2025 -0700 strlen: Fixup load alignment for memcmp Like the previous commit but for strlen copy so we can backport this commit. The loads should have the correct alignment on them so we need to create newly aligned types when the alignment of the pointer is less than the alignment of the current type. Pushed as pre-approved by https://gcc.gnu.org/pipermail/gcc-patches/2025-September/694016.html after a bootstrap/test on x86_64-linux-gnu. PR tree-optimization/121776 gcc/ChangeLog: * tree-ssa-strlen.cc (strlen_pass::handle_builtin_memcmp): Create unaligned types if the alignment of the pointers is less than the alignment of the new type. Signed-off-by: Andrew Pinski <[email protected]> (cherry picked from commit caa1c2f42691d68af4d894a5c3e700ecd2dba080) Diff: --- gcc/tree-ssa-strlen.cc | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/gcc/tree-ssa-strlen.cc b/gcc/tree-ssa-strlen.cc index b911067d009c..6651d5e88552 100644 --- a/gcc/tree-ssa-strlen.cc +++ b/gcc/tree-ssa-strlen.cc @@ -4020,8 +4020,16 @@ strlen_pass::handle_builtin_memcmp () tree ptrtype = build_pointer_type_for_mode (char_type_node, ptr_mode, true); off = build_int_cst (ptrtype, 0); - arg1 = build2_loc (loc, MEM_REF, type, arg1, off); - arg2 = build2_loc (loc, MEM_REF, type, arg2, off); + + /* Create unaligned types if needed. */ + tree type1 = type, type2 = type; + if (TYPE_ALIGN (type1) > align1) + type1 = build_aligned_type (type1, align1); + if (TYPE_ALIGN (type2) > align2) + type2 = build_aligned_type (type2, align2); + + arg1 = build2_loc (loc, MEM_REF, type1, arg1, off); + arg2 = build2_loc (loc, MEM_REF, type2, arg2, off); tree tem1 = fold_const_aggregate_ref (arg1); if (tem1) arg1 = tem1;
