On 01/29/2016 04:41 PM, Jakub Jelinek wrote:
On Fri, Jan 29, 2016 at 02:09:25AM +0100, Bernd Schmidt wrote:
I think a better approach might be to just mark accesses at known locations
in the frame, or arg pushes, as MEM_NOTRAP_P, and consider accesses with
non-constant or calculated offsets as potentially trapping.
I don't see how that would work generally. Sure, if there is e.g. a constant
offset array access, it could be checked easily, but if there is variable offset
array access, that is at some point later on changed into a constant offset
access, you'd need to be conservative, unless you can prove it is in range.
Yes. What is the problem with that? If we have (plus sfp const_int) at
any point before reload, we can check whether that offset is inside
frame_size. If it isn't or if the offset isn't known, it could trap.
Bernd
