[Bug middle-end/29749] [4.0/4.1/4.2/4.3 regression] Missing byte swap optimizations

[jakub at gcc dot gnu dot org]

------- Comment #15 from jakub at gcc dot gnu dot org  2007-12-03 22:38 -------
Subject: Bug 29749

Author: jakub
Date: Mon Dec  3 22:38:28 2007
New Revision: 130589

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=130589
Log:
        PR middle-end/29749
        * fold-const.c (fold_binary) <case BIT_AND_EXPR>: Optimize
        (X << C1) & C2 into (X << C1) & (C2 | ((1 << C1) - 1))
        and (X >> C1) & C2 into (X >> C1) & (C2 | ~((type) -1 >> C1)).
        (fold_binary) <case LSHIFT_EXPR, case RSHIFT_EXPR>: Optimize
        (X & C2) << C1 into (X << C1) & (C2 << C1) and
        (X & C2) >> C1 into (X >> C1) & (C2 >> C1) if that allows further
        optimizations.

        * gcc.dg/fold-rotate-1.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/fold-rotate-1.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/fold-const.c
    trunk/gcc/testsuite/ChangeLog


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29749