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| author | Richard Guenther <rguenther@suse.de> | 2012-03-13 13:47:35 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2012-03-13 13:47:35 +0000 |
| commit | 0c12cd5e90c8582adc5ed452d9eaa910f682b94b (patch) | |
| tree | a723864fdb306ca7d449b2c1a29153a13668ea83 /gcc/fold-const.c | |
| parent | 2895dfa4176e7739f5c5469a526d62696dc327f2 (diff) | |
| download | gcc-0c12cd5e90c8582adc5ed452d9eaa910f682b94b.zip gcc-0c12cd5e90c8582adc5ed452d9eaa910f682b94b.tar.gz gcc-0c12cd5e90c8582adc5ed452d9eaa910f682b94b.tar.bz2 | |
re PR middle-end/52134 (Does not fold (x * 4) & -4)
2012-03-13 Richard Guenther <rguenther@suse.de>
PR middle-end/52134
* fold-const.c (fold_binary_loc): Fold (X * Y) & -(1 << CST) to X * Y
if Y is a constant multiple of 1 << CST.
* gcc.dg/pr52134.c: New testcase.
From-SVN: r185334
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 0f80675..ab653ea 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -11398,6 +11398,20 @@ fold_binary_loc (location_t loc, fold_convert_loc (loc, type, arg0)); } + /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant + multiple of 1 << CST. */ + if (TREE_CODE (arg1) == INTEGER_CST) + { + double_int cst1 = tree_to_double_int (arg1); + double_int ncst1 = double_int_ext (double_int_neg (cst1), + TYPE_PRECISION (TREE_TYPE (arg1)), + TYPE_UNSIGNED (TREE_TYPE (arg1))); + if (double_int_equal_p (double_int_and (cst1, ncst1), ncst1) + && multiple_of_p (type, arg0, + double_int_to_tree (TREE_TYPE (arg1), ncst1))) + return fold_convert_loc (loc, type, arg0); + } + /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M, ((A & N) + B) & M -> (A + B) & M Similarly if (N & M) == 0, |