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long comparisons. As of this date, this change hasn't made it into the development sources. We must consider this when it comes time to integrate a newer gcc release. Thu Mar 7 01:16:23 1996 J"orn Rennecke (amylaar@meolyon.hanse.de) * expmed.c (negate_rtx): Don't negate LONG_MIN if mode is wider than HOST_WIDE_INT. gcc now produces worse code for this test case than gcc 2.5.8 when invoked with -O , but it will optimize as good as gcc 2.5.8 (i.e. all comparisons vanish) when invoked with -O2 , thus I think it doesn't matter. If anyone is interested in looking into this, the code in expr.c, function expand_expr, case MINUS_EXPR, if-clause for if (TREE_UNSIGNED (type) || TREE_OVERFLOW (negated)), will refuse to convert the subtraction into an addition if there is an overflow in the conversion or negation of the constant. If both host and target machine are binary computers with 2-complement representation, the overflow should not matter. |
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