Hi, in order to speed up astar, I had to persuade the function that decides whether a statement potentially modifies the dynamic type of an object by storing a new value to the VMT pointer to consider the following statement harmless (all types are integers of some sort):
MEM[(i32 *)b2arp_3(D) + 8B] = 0; I'd like to experiment with this routine a bit more once I have some other IPA-CP infrastructure in place but at the moment I opted for a simple solution: All scalar non-pointer stores are deemed safe. VMT pointer is a compiler generated field which is a pointer so legal user code is not able to store stuff there through some fancy type casts and compiler generated code should have no reason whatsoever to that either. Therefore I believe this change is safe and useful. I have bootstrapped and tested the patch on x886_64-linux. OK for trunk? Thanks, Martin 2011-04-14 Martin Jambor <mjam...@suse.cz> * ipa-prop.c (stmt_may_be_vtbl_ptr_store): Return false for scalar non-pointer assignments. Index: src/gcc/ipa-prop.c =================================================================== --- src.orig/gcc/ipa-prop.c +++ src/gcc/ipa-prop.c @@ -405,13 +405,18 @@ stmt_may_be_vtbl_ptr_store (gimple stmt) { tree lhs = gimple_assign_lhs (stmt); - if (TREE_CODE (lhs) == COMPONENT_REF - && !DECL_VIRTUAL_P (TREE_OPERAND (lhs, 1)) - && !AGGREGATE_TYPE_P (TREE_TYPE (lhs))) + if (!AGGREGATE_TYPE_P (TREE_TYPE (lhs))) + { + if (!POINTER_TYPE_P (TREE_TYPE (lhs))) return false; - /* In the future we might want to use get_base_ref_and_offset to find - if there is a field corresponding to the offset and if so, proceed - almost like if it was a component ref. */ + + if (TREE_CODE (lhs) == COMPONENT_REF + && !DECL_VIRTUAL_P (TREE_OPERAND (lhs, 1))) + return false; + /* In the future we might want to use get_base_ref_and_offset to find + if there is a field corresponding to the offset and if so, proceed + almost like if it was a component ref. */ + } } return true; }