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[Bug tree-optimization/34027] [4.3 regression] -Os code size nearly doubled
- From: "jakub at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 9 Nov 2007 12:30:37 -0000
- Subject: [Bug tree-optimization/34027] [4.3 regression] -Os code size nearly doubled
- References: <bug-34027-9876@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #4 from jakub at gcc dot gnu dot org 2007-11-09 12:30 -------
So then shouldn't this bug be about:
unsigned long long
foo (unsigned long long ns)
{
return ns % 1000000000L;
}
unsigned long long
bar (unsigned long long ns)
{
return ns - (ns / 1000000000L) * 1000000000L;
}
not compiling the same code at -Os? On x86_64 with -O2 it actually produces
identical code with the subtraction, supposedly that's faster. Guess even
(ns / 1000000000L) * 1000000000L should be folded into
ns - (ns % 1000000000L).
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34027