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| author | Richard Guenther <rguenth@gcc.gnu.org> | 2005-04-26 16:35:31 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2005-04-26 16:35:31 +0000 |
| commit | 70a390bbb670c358e1f933ef8e75a3a3d7ca8fa5 (patch) | |
| tree | 75a85c6c78844dca9ea04acfe5326683bc8d8c99 /gcc/fold-const.c | |
| parent | 866af8a90915d8ed191ab7af616b3a186c28cae4 (diff) | |
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re PR tree-optimization/17598 (an extra addition when comparing address of &a->b and &c->b.)
2004-04-26 Richard Guenther <rguenth@gcc.gnu.org>
PR tree-optimization/17598
* fold-const.c (fold_binary): Fold comparisons of addresses
of COMPONENT_REFs which reference the same field to
comparisons of the addresses of the base objects.
* gcc.dg/tree-ssa/pr17598.c: New testcase.
From-SVN: r98775
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 416d89e..9de988c 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -9708,6 +9708,39 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1) return t1; } + /* Fold a comparison of the address of COMPONENT_REFs with the same + type and component to a comparison of the address of the base + object. In short, &x->a OP &y->a to x OP y and + &x->a OP &y.a to x OP &y */ + if (TREE_CODE (arg0) == ADDR_EXPR + && TREE_CODE (TREE_OPERAND (arg0, 0)) == COMPONENT_REF + && TREE_CODE (arg1) == ADDR_EXPR + && TREE_CODE (TREE_OPERAND (arg1, 0)) == COMPONENT_REF) + { + tree cref0 = TREE_OPERAND (arg0, 0); + tree cref1 = TREE_OPERAND (arg1, 0); + if (TREE_OPERAND (cref0, 1) == TREE_OPERAND (cref1, 1)) + { + tree op0 = TREE_OPERAND (cref0, 0); + tree op1 = TREE_OPERAND (cref1, 0); + if (TREE_CODE (op0) == INDIRECT_REF) + op0 = TREE_OPERAND (op0, 0); + else + { + tree ptype = build_pointer_type (TREE_TYPE (op0)); + op0 = build1 (ADDR_EXPR, ptype, op0); + } + if (TREE_CODE (op1) == INDIRECT_REF) + op1 = TREE_OPERAND (op1, 0); + else + { + tree ptype = build_pointer_type (TREE_TYPE (op1)); + op1 = build1 (ADDR_EXPR, ptype, op1); + } + return fold_build2 (code, type, op0, op1); + } + } + /* If this is a comparison of complex values and either or both sides are a COMPLEX_EXPR or COMPLEX_CST, it is best to split up the comparisons and join them with a TRUTH_ANDIF_EXPR or TRUTH_ORIF_EXPR. |