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author | Richard Guenther <rguenther@suse.de> | 2009-05-03 19:55:55 +0000 |
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committer | Richard Biener <rguenth@gcc.gnu.org> | 2009-05-03 19:55:55 +0000 |
commit | 16c337707b0c71829fcad74fdc82d85b1f103eaf (patch) | |
tree | c994ca1477a25fea22b8bbec8ca9896c6a292728 /gcc | |
parent | 62a67c94b776e5d07acd247e8a68f60f2a824024 (diff) | |
download | gcc-16c337707b0c71829fcad74fdc82d85b1f103eaf.zip gcc-16c337707b0c71829fcad74fdc82d85b1f103eaf.tar.gz gcc-16c337707b0c71829fcad74fdc82d85b1f103eaf.tar.bz2 |
re PR tree-optimization/23329 (hack in may_propagate_copy should be able to removed)
2009-05-03 Richard Guenther <rguenther@suse.de>
PR middle-end/23329
* tree-ssa.c (useless_type_conversion_p_1): Use get_deref_alias_set.
Do not lose casts from array types with unknown extent to array
types with known extent.
* tree-ssa-copy.c (may_propagate_copy): Remove hack checking for
alias set compatibility.
From-SVN: r147082
Diffstat (limited to 'gcc')
-rw-r--r-- | gcc/ChangeLog | 9 | ||||
-rw-r--r-- | gcc/tree-ssa-copy.c | 49 | ||||
-rw-r--r-- | gcc/tree-ssa.c | 16 |
3 files changed, 19 insertions, 55 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 6c0bd51..581b3b5 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,12 @@ +2009-05-03 Richard Guenther <rguenther@suse.de> + + PR middle-end/23329 + * tree-ssa.c (useless_type_conversion_p_1): Use get_deref_alias_set. + Do not lose casts from array types with unknown extent to array + types with known extent. + * tree-ssa-copy.c (may_propagate_copy): Remove hack checking for + alias set compatibility. + 2009-05-03 Manuel López-Ibáñez <manu@gcc.gnu.org> * flags.h (extra_warnings): Delete. diff --git a/gcc/tree-ssa-copy.c b/gcc/tree-ssa-copy.c index f582ed0..9dad1cd 100644 --- a/gcc/tree-ssa-copy.c +++ b/gcc/tree-ssa-copy.c @@ -78,55 +78,6 @@ may_propagate_copy (tree dest, tree orig) if (!useless_type_conversion_p (type_d, type_o)) return false; - /* FIXME. GIMPLE is allowing pointer assignments and comparisons of - pointers that have different alias sets. This means that these - pointers will have different memory tags associated to them. - - If we allow copy propagation in these cases, statements de-referencing - the new pointer will now have a reference to a different memory tag - with potentially incorrect SSA information. - - This was showing up in libjava/java/util/zip/ZipFile.java with code - like: - - struct java.io.BufferedInputStream *T.660; - struct java.io.BufferedInputStream *T.647; - struct java.io.InputStream *is; - struct java.io.InputStream *is.662; - [ ... ] - T.660 = T.647; - is = T.660; <-- This ought to be type-casted - is.662 = is; - - Also, f/name.c exposed a similar problem with a COND_EXPR predicate - that was causing DOM to generate and equivalence with two pointers of - alias-incompatible types: - - struct _ffename_space *n; - struct _ffename *ns; - [ ... ] - if (n == ns) - goto lab; - ... - lab: - return n; - - I think that GIMPLE should emit the appropriate type-casts. For the - time being, blocking copy-propagation in these cases is the safe thing - to do. */ - if (TREE_CODE (dest) == SSA_NAME - && TREE_CODE (orig) == SSA_NAME - && POINTER_TYPE_P (type_d) - && POINTER_TYPE_P (type_o)) - { - if (get_alias_set (TREE_TYPE (type_d)) - != get_alias_set (TREE_TYPE (type_o))) - return false; - else if (DECL_NO_TBAA_P (SSA_NAME_VAR (dest)) - != DECL_NO_TBAA_P (SSA_NAME_VAR (orig))) - return false; - } - /* Propagating virtual operands is always ok. */ if (TREE_CODE (dest) == SSA_NAME && !is_gimple_reg (dest)) { diff --git a/gcc/tree-ssa.c b/gcc/tree-ssa.c index edbae39..10ec35b 100644 --- a/gcc/tree-ssa.c +++ b/gcc/tree-ssa.c @@ -961,12 +961,9 @@ useless_type_conversion_p_1 (tree outer_type, tree inner_type) && TYPE_VOLATILE (TREE_TYPE (outer_type))) return false; - /* Do not lose casts between pointers with different - TYPE_REF_CAN_ALIAS_ALL setting or alias sets. */ - if ((TYPE_REF_CAN_ALIAS_ALL (inner_type) - != TYPE_REF_CAN_ALIAS_ALL (outer_type)) - || (get_alias_set (TREE_TYPE (inner_type)) - != get_alias_set (TREE_TYPE (outer_type)))) + /* Do not lose casts between pointers that when dereferenced access + memory with different alias sets. */ + if (get_deref_alias_set (inner_type) != get_deref_alias_set (outer_type)) return false; /* We do not care for const qualification of the pointed-to types @@ -1002,6 +999,13 @@ useless_type_conversion_p_1 (tree outer_type, tree inner_type) if (TREE_CODE (inner_type) != TREE_CODE (outer_type)) return false; + /* Conversions from array types with unknown extent to + array types with known extent are not useless. */ + if (TREE_CODE (inner_type) == ARRAY_TYPE + && !TYPE_DOMAIN (inner_type) + && TYPE_DOMAIN (outer_type)) + return false; + /* ??? This seems to be necessary even for aggregates that don't have TYPE_STRUCTURAL_EQUALITY_P set. */ |