diff options
Diffstat (limited to 'gcc/tree-switch-conversion.c')
| -rw-r--r-- | gcc/tree-switch-conversion.c | 56 |
1 files changed, 38 insertions, 18 deletions
diff --git a/gcc/tree-switch-conversion.c b/gcc/tree-switch-conversion.c index 09c668e..ae5853b 100644 --- a/gcc/tree-switch-conversion.c +++ b/gcc/tree-switch-conversion.c @@ -246,8 +246,7 @@ This transformation was contributed by Roger Sayle, see this e-mail: struct case_bit_test { - HOST_WIDE_INT hi; - HOST_WIDE_INT lo; + wide_int mask; edge target_edge; tree label; int bits; @@ -294,13 +293,14 @@ case_bit_test_cmp (const void *p1, const void *p2) are not guaranteed to be of the same type as INDEX_EXPR (the gimplifier doesn't change the type of case label values, and MINVAL and RANGE are derived from those values). + MAXVAL is MINVAL + RANGE. There *MUST* be MAX_CASE_BIT_TESTS or less unique case node targets. */ static void emit_case_bit_tests (gimple swtch, tree index_expr, - tree minval, tree range) + tree minval, tree range, tree maxval) { struct case_bit_test test[MAX_CASE_BIT_TESTS]; unsigned int i, j, k; @@ -324,6 +324,8 @@ emit_case_bit_tests (gimple swtch, tree index_expr, tree word_type_node = lang_hooks.types.type_for_mode (word_mode, 1); tree word_mode_zero = fold_convert (word_type_node, integer_zero_node); tree word_mode_one = fold_convert (word_type_node, integer_one_node); + int prec = TYPE_PRECISION (word_type_node); + wide_int wone = wi::one (prec); memset (&test, 0, sizeof (test)); @@ -348,8 +350,7 @@ emit_case_bit_tests (gimple swtch, tree index_expr, if (k == count) { gcc_checking_assert (count < MAX_CASE_BIT_TESTS); - test[k].hi = 0; - test[k].lo = 0; + test[k].mask = wi::zero (prec); test[k].target_edge = e; test[k].label = label; test[k].bits = 1; @@ -367,14 +368,39 @@ emit_case_bit_tests (gimple swtch, tree index_expr, CASE_HIGH (cs), minval)); for (j = lo; j <= hi; j++) - if (j >= HOST_BITS_PER_WIDE_INT) - test[k].hi |= (HOST_WIDE_INT) 1 << (j - HOST_BITS_PER_INT); - else - test[k].lo |= (HOST_WIDE_INT) 1 << j; + test[k].mask |= wi::lshift (wone, j); } qsort (test, count, sizeof (*test), case_bit_test_cmp); + /* If all values are in the 0 .. BITS_PER_WORD-1 range, we can get rid of + the minval subtractions, but it might make the mask constants more + expensive. So, compare the costs. */ + if (compare_tree_int (minval, 0) > 0 + && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0) + { + int cost_diff; + HOST_WIDE_INT m = tree_to_uhwi (minval); + rtx reg = gen_raw_REG (word_mode, 10000); + bool speed_p = optimize_bb_for_speed_p (gimple_bb (swtch)); + cost_diff = set_rtx_cost (gen_rtx_PLUS (word_mode, reg, + GEN_INT (-m)), speed_p); + for (i = 0; i < count; i++) + { + rtx r = immed_wide_int_const (test[i].mask, word_mode); + cost_diff += set_src_cost (gen_rtx_AND (word_mode, reg, r), speed_p); + r = immed_wide_int_const (wi::lshift (test[i].mask, m), word_mode); + cost_diff -= set_src_cost (gen_rtx_AND (word_mode, reg, r), speed_p); + } + if (cost_diff > 0) + { + for (i = 0; i < count; i++) + test[i].mask = wi::lshift (test[i].mask, m); + minval = build_zero_cst (TREE_TYPE (minval)); + range = maxval; + } + } + /* We generate two jumps to the default case label. Split the default edge, so that we don't have to do any PHI node updating. */ @@ -446,13 +472,7 @@ emit_case_bit_tests (gimple swtch, tree index_expr, if (const & csui) goto target */ for (k = 0; k < count; k++) { - HOST_WIDE_INT a[2]; - - a[0] = test[k].lo; - a[1] = test[k].hi; - tmp = wide_int_to_tree (word_type_node, - wide_int::from_array (a, 2, - TYPE_PRECISION (word_type_node))); + tmp = wide_int_to_tree (word_type_node, test[k].mask); tmp = fold_build2 (BIT_AND_EXPR, word_type_node, csui, tmp); tmp = force_gimple_operand_gsi (&gsi, tmp, /*simple=*/true, NULL_TREE, @@ -1369,8 +1389,8 @@ process_switch (gimple swtch) { if (dump_file) fputs (" expanding as bit test is preferable\n", dump_file); - emit_case_bit_tests (swtch, info.index_expr, - info.range_min, info.range_size); + emit_case_bit_tests (swtch, info.index_expr, info.range_min, + info.range_size, info.range_max); loops_state_set (LOOPS_NEED_FIXUP); return NULL; } |