------- Additional Comments From kazu at cs dot umass dot edu 2005-04-28 19:33 ------- Diego,
I think it's OK to have contradictory information from an ASSERT_EXPR and SCEV. Let's say we have a loop counting from i = 0 upward. It's possible that we "if (i < 0)" in the loop and see something like i_10 = ASSERT_EXPR <i_1, i_1 < 0>; on the "then" arm of the conditional. In this case, we know we are counting upward, so SCEV tells us that the minimum value of i_10 should be 0, but the ASSERT_EXPR tells us that the range should be [-INF, -1]. They are completely disjoint! This weird situation comes from the fact that the "then" branch of the conditional is dead. In this case, probably the safest and simplest thing to do is to ignoring what SCEV says. Kazu Hirata -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21030
