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| author | Kazu Hirata <kazu@cs.umass.edu> | 2003-03-20 16:10:36 +0000 |
|---|---|---|
| committer | Kazu Hirata <kazu@gcc.gnu.org> | 2003-03-20 16:10:36 +0000 |
| commit | 015c318662801cd61e48698362d3d11151fbfdfa (patch) | |
| tree | febe4386bb8881ee4e27be3b484e32721d352557 /gcc | |
| parent | 101cb92aa6a16a51b5011cca84e2d2d1600cad4e (diff) | |
| download | gcc-015c318662801cd61e48698362d3d11151fbfdfa.zip gcc-015c318662801cd61e48698362d3d11151fbfdfa.tar.gz gcc-015c318662801cd61e48698362d3d11151fbfdfa.tar.bz2 | |
* fold-const.c (fold): Fold A - (A & B) into ~B & A.
From-SVN: r64615
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/fold-const.c | 16 |
2 files changed, 20 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 0f58a3f..d20b175 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,7 @@ +2003-03-20 Kazu Hirata <kazu at cs dot umass dot edu> + + * fold-const.c (fold): Fold A - (A & B) into ~B & A. + 2003-03-20 Kazu Hirata <kazu@cs.umass.edu> * config/h8300/h8300.md (a peephole2): New. diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 48c3683..4890c17 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -5560,6 +5560,22 @@ fold (expr) TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0))), TREE_OPERAND (arg0, 1))); + + /* Fold A - (A & B) into ~B & A. */ + if (!TREE_SIDE_EFFECTS (arg0) + && TREE_CODE (arg1) == BIT_AND_EXPR) + { + if (operand_equal_p (arg0, TREE_OPERAND (arg1, 1), 0)) + return fold (build (BIT_AND_EXPR, type, + fold (build1 (BIT_NOT_EXPR, type, + TREE_OPERAND (arg1, 0))), + arg0)); + if (operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) + return fold (build (BIT_AND_EXPR, type, + fold (build1 (BIT_NOT_EXPR, type, + TREE_OPERAND (arg1, 1))), + arg0)); + } } /* See if ARG1 is zero and X - ARG1 reduces to X. */ |