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| author | Aldy Hernandez <aldyh@redhat.com> | 2020-06-02 11:57:18 +0200 |
|---|---|---|
| committer | Aldy Hernandez <aldyh@redhat.com> | 2020-06-02 14:02:35 +0200 |
| commit | f5372d34d4467ec2c63d212b1f6ee8e302c08b0c (patch) | |
| tree | b212b83300aba06742a9994849c424805937725a | |
| parent | 455c0b2c72dfc6eb3bc753e8e1f54906c1ada484 (diff) | |
| download | gcc-f5372d34d4467ec2c63d212b1f6ee8e302c08b0c.zip gcc-f5372d34d4467ec2c63d212b1f6ee8e302c08b0c.tar.gz gcc-f5372d34d4467ec2c63d212b1f6ee8e302c08b0c.tar.bz2 | |
Fix operator_bitwise_and::remove_impossible_ranges so that masks wider than 32-bit work.
| -rw-r--r-- | gcc/range-op.cc | 33 |
1 files changed, 26 insertions, 7 deletions
diff --git a/gcc/range-op.cc b/gcc/range-op.cc index 3676dc8..434fc92 100644 --- a/gcc/range-op.cc +++ b/gcc/range-op.cc @@ -1966,7 +1966,7 @@ operator_bitwise_and::remove_impossible_ranges (irange &r, tree tree_mask; mask.singleton_p (&tree_mask); - if (!tree_fits_uhwi_p (tree_mask)) // ?? Rewrite with wide_int's. + if (!tree_fits_uhwi_p (tree_mask)) // FIXME: Rewrite with wide_int's. return; unsigned HOST_WIDE_INT int_mask = tree_to_uhwi (tree_mask); @@ -1976,17 +1976,18 @@ operator_bitwise_and::remove_impossible_ranges (irange &r, widest_irange impossible_ranges; /* We know that starting at the most significant bit, any 0 in the - mask is impossible, so the following ranges are impossible: + mask means the resulting range cannot contain a 1 in that same + position. This means the following ranges are impossible: x & 0b1001 1010 IMPOSSIBLE RANGES - 0b01xx xxxx [0100 0000, 0111 1111] - 0b001x xxxx [0010 0000, 0011 1111] - 0b0000 01xx [0000 0100, 0000 0111] - 0b0000 0001 [0000 0001, 0000 0001] + 01xx xxxx [0100 0000, 0111 1111] + 001x xxxx [0010 0000, 0011 1111] + 0000 01xx [0000 0100, 0000 0111] + 0000 0001 [0000 0001, 0000 0001] */ for (int i = 0; i < prec - leading_zeros - 1; ++i) - if ((int_mask & (1 << i)) == 0) + if ((int_mask & ((unsigned HOST_WIDE_INT)1 << i)) == 0) { tree lb = fold_build2 (LSHIFT_EXPR, type, build_one_cst (type), @@ -3464,6 +3465,24 @@ operator_tests () i1 = int_range<1> (integer_type_node); op_bitwise_and.op1_range (res, integer_type_node, i1, i2); ASSERT_TRUE (res == int_range<1> (integer_type_node)); + + // Test that 0x808.... & 0x8.... still contains 0x8.... + // for a large set of numbers. + { + tree big_type = long_long_unsigned_type_node; + // big_num = 0x808,0000,0000,0000 + tree big_num = fold_build2 (LSHIFT_EXPR, big_type, + build_int_cst (big_type, 0x808), + build_int_cst (big_type, 48)); + op_bitwise_and.fold_range (res, big_type, + int_range <1> (big_type), + int_range <1> (big_num, big_num)); + // val = 0x8,0000,0000,0000 + tree val = fold_build2 (LSHIFT_EXPR, big_type, + build_int_cst (big_type, 0x8), + build_int_cst (big_type, 48)); + ASSERT_TRUE (res.contains_p (val)); + } } // Run all of the selftests within this file. |