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| author | Richard Guenther <rguenther@suse.de> | 2011-05-30 11:15:20 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2011-05-30 11:15:20 +0000 |
| commit | f33211587118865c4f26f3806355441c4dfdb8b8 (patch) | |
| tree | 461b8951a8882fd9c13e1232291f8e317d76f105 /gcc/tree-vrp.c | |
| parent | d12d8efea8fcb3122b78b3eafb7e35fe7ec2f4bd (diff) | |
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re PR tree-optimization/49218 (Incorrect optimization of a 'for' loop creates an infinite loop)
2011-05-30 Richard Guenther <rguenther@suse.de>
PR tree-optimization/49218
* tree-vrp.c (adjust_range_with_scev): Properly check whether
overflow occured.
* gcc.c-torture/execute/pr49218.c: New testcase.
From-SVN: r174429
Diffstat (limited to 'gcc/tree-vrp.c')
| -rw-r--r-- | gcc/tree-vrp.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c index 8fcf629..f40d0d4 100644 --- a/gcc/tree-vrp.c +++ b/gcc/tree-vrp.c @@ -3423,11 +3423,17 @@ adjust_range_with_scev (value_range_t *vr, struct loop *loop, loop->nb_iterations_upper_bound, double_int_one), unsigned_p, &overflow); - tem = double_int_to_tree (TREE_TYPE (init), dtmp); /* If the multiplication overflowed we can't do a meaningful - adjustment. */ - if (!overflow && double_int_equal_p (dtmp, tree_to_double_int (tem))) - { + adjustment. Likewise if the result doesn't fit in the type + of the induction variable. For a signed type we have to + check whether the result has the expected signedness which + is that of the step as nb_iterations_upper_bound is unsigned. */ + if (!overflow + && double_int_fits_to_tree_p (TREE_TYPE (init), dtmp) + && (unsigned_p + || ((dtmp.high ^ TREE_INT_CST_HIGH (step)) >= 0))) + { + tem = double_int_to_tree (TREE_TYPE (init), dtmp); extract_range_from_binary_expr (&maxvr, PLUS_EXPR, TREE_TYPE (init), init, tem); /* Likewise if the addition did. */ |