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| author | Xinliang David Li <davidxl@gcc.gnu.org> | 2010-04-20 17:00:37 +0000 |
|---|---|---|
| committer | Xinliang David Li <davidxl@gcc.gnu.org> | 2010-04-20 17:00:37 +0000 |
| commit | 94e85e0ae88fee653abdfe33244da282dd44184d (patch) | |
| tree | cfb7472bcd31a0ac649da7ca0ba1431b1f0ee0ad /gcc/fold-const.c | |
| parent | 54fb1ae03e7eda76d322545955cd128412887d23 (diff) | |
| download | gcc-94e85e0ae88fee653abdfe33244da282dd44184d.zip gcc-94e85e0ae88fee653abdfe33244da282dd44184d.tar.gz gcc-94e85e0ae88fee653abdfe33244da282dd44184d.tar.bz2 | |
new folding rule
From-SVN: r158567
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 28 |
1 files changed, 26 insertions, 2 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 85f9cd1..cdae661 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -8643,9 +8643,33 @@ fold_comparison (location_t loc, enum tree_code code, tree type, offset1 = TREE_OPERAND (arg1, 1); } + /* A local variable can never be pointed to by + the default SSA name of an incoming parameter. */ + if ((TREE_CODE (arg0) == ADDR_EXPR + && indirect_base0 + && TREE_CODE (base0) == VAR_DECL + && auto_var_in_fn_p (base0, current_function_decl) + && !indirect_base1 + && TREE_CODE (base1) == SSA_NAME + && TREE_CODE (SSA_NAME_VAR (base1)) == PARM_DECL + && SSA_NAME_IS_DEFAULT_DEF (base1)) + || (TREE_CODE (arg1) == ADDR_EXPR + && indirect_base1 + && TREE_CODE (base1) == VAR_DECL + && auto_var_in_fn_p (base1, current_function_decl) + && !indirect_base0 + && TREE_CODE (base0) == SSA_NAME + && TREE_CODE (SSA_NAME_VAR (base0)) == PARM_DECL + && SSA_NAME_IS_DEFAULT_DEF (base0))) + { + if (code == NE_EXPR) + return constant_boolean_node (1, type); + else if (code == EQ_EXPR) + return constant_boolean_node (0, type); + } /* If we have equivalent bases we might be able to simplify. */ - if (indirect_base0 == indirect_base1 - && operand_equal_p (base0, base1, 0)) + else if (indirect_base0 == indirect_base1 + && operand_equal_p (base0, base1, 0)) { /* We can fold this expression to a constant if the non-constant offset parts are equal. */ |