diff options
| author | rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2011-05-20 15:02:49 +0000 |
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| committer | rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2011-05-20 15:02:49 +0000 |
| commit | 06ec5ac445869acdd61d1e7cd686d1dbed81f4d5 (patch) | |
| tree | 0f88181acea8ab0fc265d45d99e9be13fd4739e8 /gcc/tree-dfa.c | |
| parent | 6ae2c05184201f8301277f98f0ab314c63ede0c5 (diff) | |
| download | gcc-06ec5ac445869acdd61d1e7cd686d1dbed81f4d5.tar.gz | |
2011-05-20 Richard Guenther <rguenther@suse.de>
PR tree-optimization/49079
* tree-dfa.c (get_ref_base_and_extent): Handle view-converting
MEM_REFs correctly for the trailing array access detection.
Special case constants the same way as decls for overall size
constraining.
* gcc.dg/torture/pr49079.c: New testcase.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@173954 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/tree-dfa.c')
| -rw-r--r-- | gcc/tree-dfa.c | 28 |
1 files changed, 20 insertions, 8 deletions
diff --git a/gcc/tree-dfa.c b/gcc/tree-dfa.c index 70e3c1d35cd..9791bccecae 100644 --- a/gcc/tree-dfa.c +++ b/gcc/tree-dfa.c @@ -714,6 +714,7 @@ get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset, tree size_tree = NULL_TREE; HOST_WIDE_INT bit_offset = 0; bool seen_variable_array_ref = false; + tree base_type; /* First get the final access size from just the outermost expression. */ if (TREE_CODE (exp) == COMPONENT_REF) @@ -744,6 +745,8 @@ get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset, and find the ultimate containing object. */ while (1) { + base_type = TREE_TYPE (exp); + switch (TREE_CODE (exp)) { case BIT_FIELD_REF: @@ -931,9 +934,16 @@ get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset, the array. The simplest way to conservatively deal with this is to punt in the case that offset + maxsize reaches the base type boundary. This needs to include possible trailing padding - that is there for alignment purposes. + that is there for alignment purposes. */ + + if (seen_variable_array_ref + && maxsize != -1 + && (!host_integerp (TYPE_SIZE (base_type), 1) + || (bit_offset + maxsize + == (signed) TREE_INT_CST_LOW (TYPE_SIZE (base_type))))) + maxsize = -1; - That is of course only true if the base object is not a decl. */ + /* In case of a decl or constant base object we can do better. */ if (DECL_P (exp)) { @@ -943,12 +953,14 @@ get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset, && host_integerp (DECL_SIZE (exp), 1)) maxsize = TREE_INT_CST_LOW (DECL_SIZE (exp)) - bit_offset; } - else if (seen_variable_array_ref - && maxsize != -1 - && (!host_integerp (TYPE_SIZE (TREE_TYPE (exp)), 1) - || (bit_offset + maxsize - == (signed) TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (exp)))))) - maxsize = -1; + else if (CONSTANT_CLASS_P (exp)) + { + /* If maxsize is unknown adjust it according to the size of the + base type constant. */ + if (maxsize == -1 + && host_integerp (TYPE_SIZE (TREE_TYPE (exp)), 1)) + maxsize = TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (exp))) - bit_offset; + } /* ??? Due to negative offsets in ARRAY_REF we can end up with negative bit_offset here. We might want to store a zero offset |