[Bug tree-optimization/56902] Fails to SLP with mismatched +/- and negatable constants
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56902 Richard Biener changed: What|Removed |Added Status|UNCONFIRMED |RESOLVED Known to work||6.0 Resolution|--- |FIXED --- Comment #4 from Richard Biener --- This is now fixed. Note + 3. vs. - 3. should be handled more optimally (PR68050)
[Bug tree-optimization/56902] Fails to SLP with mismatched +/- and negatable constants
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56902 --- Comment #3 from Cong Hou --- How do you generate the final operations in vectorized code? I just submitted a patch on this issue. The patch supports non-isomorphic operations with the restriction that all operations on even/odd elements still be isomorphic. Please give me the comment on this patch. Thank you! Cong
[Bug tree-optimization/56902] Fails to SLP with mismatched +/- and negatable constants
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56902 --- Comment #2 from Richard Biener --- Created attachment 31209 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=31209&action=edit hack Btw, I also had a patch^Whack, see attached. Also further patches that didn't get merged to take care of vectorizing PR37021 better.
[Bug tree-optimization/56902] Fails to SLP with mismatched +/- and negatable constants
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56902 Cong Hou changed: What|Removed |Added CC||congh at google dot com --- Comment #1 from Cong Hou --- I just made a patch which supports limited non-isomorphic operations (operations on even/odd elements are still isomorphic) for SLP. Then the three loops you listed can be vectorized using SLP by using new VEC_ADDSUB_EXPR or VEC_SUBADD_EXPR. For x86, SSE3 provides ADDSUBPD/ADDSUBPS instructions which can do the job, but I also emulated them for SSE (use mask to negate the even/odd elements and then add). I think we will need to support more general non-isomorphic operations, which is more difficult and challenging. But I think the limited support in this patch is also useful at this time. I will send the patch later.
