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[Bug target/37390] wrong-code on i486-linux-gnu with -O[12], -O0 works
- From: "vincent at vinc17 dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 6 Sep 2008 22:19:21 -0000
- Subject: [Bug target/37390] wrong-code on i486-linux-gnu with -O[12], -O0 works
- References: <bug-37390-11764@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #11 from vincent at vinc17 dot org 2008-09-06 22:19 -------
(In reply to comment #10)
> The funny thing is that this only happens with -O2 or -O1 but not with -O0 ie
> no optimization it is all correct , when we optimize the results start varying.
Because with -O0, some values are stored to memory and re-read from memory,
hence rounded to double precision (53-bit significand), a bit like with
-ffloat-store.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37390