The repeated checks for MEM_REF made this code hard to convert to poly_ints as-is. Hopefully the new structure also makes it clearer at a glance what the two cases are.
2017-10-23 Richard Sandiford <richard.sandif...@linaro.org> Alan Hayward <alan.hayw...@arm.com> David Sherwood <david.sherw...@arm.com> gcc/ * tree-ssa-sccvn.c (vn_reference_lookup_3): Avoid repeated checks for MEM_REF. Index: gcc/tree-ssa-sccvn.c =================================================================== --- gcc/tree-ssa-sccvn.c 2017-10-23 11:47:03.852769480 +0100 +++ gcc/tree-ssa-sccvn.c 2017-10-23 11:47:44.596155858 +0100 @@ -2234,6 +2234,7 @@ vn_reference_lookup_3 (ao_ref *ref, tree || offset % BITS_PER_UNIT != 0 || ref->size % BITS_PER_UNIT != 0) return (void *)-1; + at = offset / BITS_PER_UNIT; /* Extract a pointer base and an offset for the destination. */ lhs = gimple_call_arg (def_stmt, 0); @@ -2301,19 +2302,18 @@ vn_reference_lookup_3 (ao_ref *ref, tree copy_size = tree_to_uhwi (gimple_call_arg (def_stmt, 2)); /* The bases of the destination and the references have to agree. */ - if ((TREE_CODE (base) != MEM_REF - && !DECL_P (base)) - || (TREE_CODE (base) == MEM_REF - && (TREE_OPERAND (base, 0) != lhs - || !tree_fits_uhwi_p (TREE_OPERAND (base, 1)))) - || (DECL_P (base) - && (TREE_CODE (lhs) != ADDR_EXPR - || TREE_OPERAND (lhs, 0) != base))) + if (TREE_CODE (base) == MEM_REF) + { + if (TREE_OPERAND (base, 0) != lhs + || !tree_fits_uhwi_p (TREE_OPERAND (base, 1))) + return (void *) -1; + at += tree_to_uhwi (TREE_OPERAND (base, 1)); + } + else if (!DECL_P (base) + || TREE_CODE (lhs) != ADDR_EXPR + || TREE_OPERAND (lhs, 0) != base) return (void *)-1; - at = offset / BITS_PER_UNIT; - if (TREE_CODE (base) == MEM_REF) - at += tree_to_uhwi (TREE_OPERAND (base, 1)); /* If the access is completely outside of the memcpy destination area there is no aliasing. */ if (lhs_offset >= at + maxsize / BITS_PER_UNIT