-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 04/03/11 19:44, Nathan Froyd wrote: > The patch below converts gcse.c:canon_modify_mem_list to hold VECs > instead of EXPR_LIST rtxes. I am ambivalent about the use of VECs in > canon_modify_mem_list; they will waste some memory compared to the > linked list scheme present before, though I'm not sure how much. It > would depend on the average chain length, etc. I'm happy to use an > linked list datastructure instead, allocated out of an > alloc_pool (better statistics!) or even gcse's private obstack if folks > think that would be better. Moving things out of GC memory and > eliminating a use of EXPR_LIST has to be considered a good thing, > though... I've got no strong opinions on all this stuff -- except that blindly moving stuff out of GC memory isn't necessarily a good thing. It really depends on the lifetime of the objects.
Assuming the memory list stuff in gcse doesn't have a lifetime outside of GCSE and is thus easily tracked, then I've got no fundamental objection to the change. > > Doing this required addressing an odd little comment in > record_last_mem_set_info: > > if (CALL_P (insn)) > { > /* Note that traversals of this loop (other than for free-ing) > will break after encountering a CALL_INSN. So, there's no > need to insert a pair of items, as canon_list_insert does. */ > canon_modify_mem_list[bb] = > alloc_INSN_LIST (insn, canon_modify_mem_list[bb]); > bitmap_set_bit (blocks_with_calls, bb); > } > > This is all well and good, except that the only real traversal of > canon_modify_mem_list (compute_transp) doesn't check for CALL_INSNs. It's possible (likely?) the implementation changed over time and the comment wasn't properly updated. Unfortunate, but it does happen. > + canon_modify_mem_list = GCNEWVEC (VEC(modify_pair,heap) *, > + last_basic_block); nit; You're missing some whitespace here (after the VEC). OK. Please install, Thanks, Jeff -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJNmgdkAAoJEBRtltQi2kC7QagH/AkchggJ4C7SU2AasolDyQqn tcQowd5zBmiYFujY9+UgIL6Wh6AVU/Ls452c96MVKKWcDi8kIW0y3tzlls5yYbKW /XtvuzPU9zhya672mjTNktD3mPFj4qKtAO7PsjCh375uvkSknSXCAP9B5O9nQPbR BdaaAHv4gLgrpIokFTxk5455/7BGMCNJ0/O91PR4Jyithc2wZsz6Me4AFg+aMZG/ t+Vq7+6D5kALiXrrn2UNzrGefE6i6HdbacP6drOaDI1XNmI8Se4NgiE/JQfkvKty 1i4MVGW2IJrMax7fCKLhIRErQxEgfGQVfOLk5WkQXSzxfvILLu1bkdTTLKTr6t0= =tTk7 -----END PGP SIGNATURE-----