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| author | Jakub Jelinek <jakub@redhat.com> | 2015-01-12 21:44:32 +0100 |
|---|---|---|
| committer | Jakub Jelinek <jakub@gcc.gnu.org> | 2015-01-12 21:44:32 +0100 |
| commit | f51286f21f3b69878d9b5d55041089aba79c82a6 (patch) | |
| tree | 0217d8864283be08a04517b8666b0763b5234f11 /gcc/tree-vrp.c | |
| parent | 01991953449246570f85f30b7b37e29a7e5b2cc1 (diff) | |
| download | gcc-f51286f21f3b69878d9b5d55041089aba79c82a6.zip gcc-f51286f21f3b69878d9b5d55041089aba79c82a6.tar.gz gcc-f51286f21f3b69878d9b5d55041089aba79c82a6.tar.bz2 | |
re PR tree-optimization/64454 (optimize (x%5)%5)
PR tree-optimization/64454
* tree-vrp.c (simplify_div_or_mod_using_ranges): Optimize
op0 % op1 into op0 if op0 is in range [-op1 + 1, op1 - 1]
for signed or [0, op1 - 1] for unsigned modulo.
(simplify_stmt_using_ranges): Call simplify_div_or_mod_using_ranges
even if op1 does not satisfy integer_pow2p.
* gcc.dg/pr64454.c: New test.
From-SVN: r219491
Diffstat (limited to 'gcc/tree-vrp.c')
| -rw-r--r-- | gcc/tree-vrp.c | 40 |
1 files changed, 35 insertions, 5 deletions
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c index ae1da46..ecf86c3 100644 --- a/gcc/tree-vrp.c +++ b/gcc/tree-vrp.c @@ -8998,7 +8998,11 @@ simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt) /* Simplify a division or modulo operator to a right shift or bitwise and if the first operand is unsigned or is greater - than zero and the second operand is an exact power of two. */ + than zero and the second operand is an exact power of two. + For TRUNC_MOD_EXPR op0 % op1 with constant op1, optimize it + into just op0 if op0's range is known to be a subset of + [-op1 + 1, op1 - 1] for signed and [0, op1 - 1] for unsigned + modulo. */ static bool simplify_div_or_mod_using_ranges (gimple stmt) @@ -9007,7 +9011,30 @@ simplify_div_or_mod_using_ranges (gimple stmt) tree val = NULL; tree op0 = gimple_assign_rhs1 (stmt); tree op1 = gimple_assign_rhs2 (stmt); - value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt)); + value_range_t *vr = get_value_range (op0); + + if (rhs_code == TRUNC_MOD_EXPR + && TREE_CODE (op1) == INTEGER_CST + && tree_int_cst_sgn (op1) == 1 + && range_int_cst_p (vr) + && tree_int_cst_lt (vr->max, op1)) + { + if (TYPE_UNSIGNED (TREE_TYPE (op0)) + || tree_int_cst_sgn (vr->min) >= 0 + || tree_int_cst_lt (fold_unary (NEGATE_EXPR, TREE_TYPE (op1), op1), + vr->min)) + { + /* If op0 already has the range op0 % op1 has, + then TRUNC_MOD_EXPR won't change anything. */ + gimple_stmt_iterator gsi = gsi_for_stmt (stmt); + gimple_assign_set_rhs_from_tree (&gsi, op0); + update_stmt (stmt); + return true; + } + } + + if (!integer_pow2p (op1)) + return false; if (TYPE_UNSIGNED (TREE_TYPE (op0))) { @@ -9880,11 +9907,14 @@ simplify_stmt_using_ranges (gimple_stmt_iterator *gsi) /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR and BIT_AND_EXPR respectively if the first operand is greater - than zero and the second operand is an exact power of two. */ + than zero and the second operand is an exact power of two. + Also optimize TRUNC_MOD_EXPR away if the second operand is + constant and the first operand already has the right value + range. */ case TRUNC_DIV_EXPR: case TRUNC_MOD_EXPR: - if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) - && integer_pow2p (gimple_assign_rhs2 (stmt))) + if (TREE_CODE (rhs1) == SSA_NAME + && INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) return simplify_div_or_mod_using_ranges (stmt); break; |