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[Bug c/47977] powerpc (-mcpu=8548) Wrong code for double operations in little endian mode
- From: "froydnj at codesourcery dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Thu, 3 Mar 2011 16:51:39 +0000
- Subject: [Bug c/47977] powerpc (-mcpu=8548) Wrong code for double operations in little endian mode
- Auto-submitted: auto-generated
- References: <bug-47977-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47977
--- Comment #2 from froydnj at codesourcery dot com <froydnj at codesourcery dot com> 2011-03-03 16:51:18 UTC ---
On Thu, Mar 03, 2011 at 04:08:53PM +0000, m.lazzarotto at robox dot it wrote:
> lwz 9,8(1) # What's the purpose ?
> lwz 10,12(1) # What's the purpose ?
> stw 9,8(1) # What's the purpose ?
> stw 10,12(1) # What's the purpose ?
These are an artifact of the lower-subreg pass; the E500 bits contain
some logic to clean up spurious moves introduced by using E500
floating-point, but the lower-subreg pass stymies those bits of logic.
A separate bug for a (sub-)target-specific pass to clean those artifacts
up would be appropriate, but I don't think it's going to happen any time
soon.