[Bug tree-optimization/33565] [4.3 regression] spurious warning: assuming signed overflow does not occur when assuming that (X + c) >= X is always true

[ian at gcc dot gnu dot org]

------- Comment #3 from ian at gcc dot gnu dot org  2007-09-27 17:31 -------
Subject: Bug 33565

Author: ian
Date: Thu Sep 27 17:31:34 2007
New Revision: 128840

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=128840
Log:
./:
        PR tree-optimization/33565
        * tree-ssa-loop-ch.c (copy_loop_headers): Set TREE_NO_WARNING on
        assignments of comparisons.
        * tree-ssa-sccvn.c (simplify_binary_expression): Add stmt
        parameter.  Change caller.  Defer overflow warnings around call to
        fold_binary.
        * fold-const.c (fold_undefer_overflow_warnings): Don't warn if
        TREE_NO_WARNING is set on the statement.
        * tree-ssa-forwprop.c
        (tree_ssa_forward_propagate_single_use_vars): Don't test
        TREE_NO_WARNING when calling fold_undefer_overflow_warnings.
        * tree-cfg.c (fold_cond_expr_cond): Likewise.
testsuite/:
        PR tree-optimization/33565
        * gcc.dg/Wstrict-overflow-20.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/Wstrict-overflow-20.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/fold-const.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-cfg.c
    trunk/gcc/tree-ssa-forwprop.c
    trunk/gcc/tree-ssa-loop-ch.c
    trunk/gcc/tree-ssa-sccvn.c


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33565