[Bug tree-optimization/15791] fold misses that two ADDR_EXPR of an arrary obvious not equal

[rguenth at tat dot physik dot uni-tuebingen dot de]

------- Additional Comments From rguenth at tat dot physik dot uni-tuebingen dot de  2005-01-26 16:16 -------
Umm, no.  We fold the ARRAY_REF comparison to

PLUS_EXPR(ADDR_EXPR, INTEGER_CST) == PLUS_EXPR(ADDR_EXPR, INTEGER_CST)

oh well ;)  So I guess transforming &a + i truth_op &a + j to i truth_op j
is always correct, as &a - &a == 0.

For &b[1] == b though, we'll have to do more checks for this.

Patch attached, bootstrap and testing in progress.

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15791