http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46172
--- Comment #5 from Ira Rosen <irar at il dot ibm.com> 2010-11-02 13:28:14 UTC --- (In reply to comment #4) > Ah, if this is in dead code created by vectorizer that really shouldn't be > ever > expanded, Yes, in this case it's dead code created by the vectorizer that shouldn't be expanded. But there is also always scalar code that we do not remove except for stores. > then either we need to arrange for DCE to be performed after > vectorizer even if flag_tree_vectorize && !flag_tree_dce (e.g. by using a > different pass structure e.g. instead of pass_dce_loop and use a different > gate > for it right after vectorizer), Yes, this is what I meant. > or vectorizer shouldn't create garbage. > > -fno-tree-dce is sometimes useful for compiler testing to write testcases e.g. > for expansion and RTL passes bugs, so making it unconditional is not a good > idea.
