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| author | rth <rth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2003-04-07 22:57:41 +0000 |
|---|---|---|
| committer | rth <rth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2003-04-07 22:57:41 +0000 |
| commit | a86696c32abbde9a61f5bb9af8e19b5ad80e3bc8 (patch) | |
| tree | 5c9af0f6f2b13994e8a18e00191c5bf0c49f5ad6 /gcc/explow.c | |
| parent | 930f9e9226cc2fcb3ea841193b3b41e056ee61c5 (diff) | |
| download | gcc-a86696c32abbde9a61f5bb9af8e19b5ad80e3bc8.tar.gz | |
PR opt/8634
* explow.c (maybe_set_unchanging): Don't flag non-static const
aggregate type initializers with RTX_UNCHANGING_P.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@65352 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/explow.c')
| -rw-r--r-- | gcc/explow.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/gcc/explow.c b/gcc/explow.c index 50556e8d6bf..9ed034eb1a9 100644 --- a/gcc/explow.c +++ b/gcc/explow.c @@ -657,8 +657,18 @@ maybe_set_unchanging (ref, t) /* We can set RTX_UNCHANGING_P from TREE_READONLY for decls whose initialization is only executed once, or whose initializer always has the same value. Currently we simplify this to PARM_DECLs in the - first case, and decls with TREE_CONSTANT initializers in the second. */ + first case, and decls with TREE_CONSTANT initializers in the second. + + We cannot do this for non-static aggregates, because of the double + writes that can be generated by store_constructor, depending on the + contents of the initializer. Yes, this does eliminate a good fraction + of the number of uses of RTX_UNCHANGING_P for a language like Ada. + It also eliminates a good quantity of bugs. Let this be incentive to + eliminate RTX_UNCHANGING_P entirely in favour of a more reliable + solution, perhaps based on alias sets. */ + if ((TREE_READONLY (t) && DECL_P (t) + && (TREE_STATIC (t) || ! AGGREGATE_TYPE_P (TREE_TYPE (t))) && (TREE_CODE (t) == PARM_DECL || (DECL_INITIAL (t) && TREE_CONSTANT (DECL_INITIAL (t))))) || TREE_CODE_CLASS (TREE_CODE (t)) == 'c') |