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[Bug middle-end/18908] Missed folding opportunities with bools
- From: "rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 19 Jul 2011 08:34:01 +0000
- Subject: [Bug middle-end/18908] Missed folding opportunities with bools
- Auto-submitted: auto-generated
- References: <bug-18908-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18908
--- Comment #15 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-07-19 08:33:23 UTC ---
On x86_64 we have
f3:
.LFB2:
.cfi_startproc
xorb $1, (%rdi)
andb $1, (%rdi)
ret
already, thus only a truncation to bitfield precision is left.
As we expand ~*p as *p ^ 1 folding on the tree level isn't strictly necessary
so this is a missed opt on RTL or expand.