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4fa26a6079
* flags.h (flag_wrapv): New flag controlling overflow semantics. * toplev.c (flag_wrapv): Declare the variable with default false. (lang_independent_options): New option "-fwrapv" to set the above. * fold-const.c (extract_muldiv_1): Disable optimization of (2*x)/2 as x, when signed arithmetic overflow wraps around. (fold): Optimize "-A - B" as "-B - A" if overflow wraps around. * loop.c (basic_induction_var): Ignore BIVs that rely on undefined overflow when flag_wrapv is true. * java/lang.c (java_init_options): Prescribe wrap-around two's complement arithmetic overflow by setting flag_wrapv. * doc/invoke.texi: Document new -fwrapv command line option. * doc/c-tree.texi: Mention that the overflow semantics of NEGATE_EXPR, PLUS_EXPR, MINUS_EXPR and MULT_EXPR is dependent upon both flag_wrapv and flag_trapv. * gcc.dg/fwrapv-1.c: New test case. * gcc.dg/fwrapv-2.c: New test case. * libjava.lang/Overflow.java: New test. * libjava.lang/Overflow.out: New file. From-SVN: r67270
17 lines
214 B
Java
17 lines
214 B
Java
class Overflow
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{
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static int test(int x)
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{
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return (2*x)/2;
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}
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public static void main(String argv[])
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{
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int x = Integer.MAX_VALUE;
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if (test(x) == x)
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throw new RuntimeException ();
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}
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}
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