[Bug tree-optimization/28230] [4.2 Regression] -O2 -fwrapv miscompiles gcc, binutils, gzip.

steven at gcc dot gnu dot org gcc-bugzilla@gcc.gnu.org
Sun Sep 24 10:08:00 GMT 2006



------- Comment #15 from steven at gcc dot gnu dot org  2006-09-24 10:08 -------
Significant difference:

n_15: [0, +INF]  EQUIVALENCES: { } (0 elements)  without -fwrapv
n_15: [1, 65534]  EQUIVALENCES: { } (0 elements) with -fwrapv

With -fwrapv this results in:

Folding predicate n_15 != 0 to 1
Folded statement: if (n_15 != 0) goto <L7>; else goto <L6>;
            into: if (1) goto <L7>; else goto <L6>;

which is the infinite loop here.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28230



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