On Thu, Jul 7, 2011 at 6:07 PM, Kai Tietz <ktiet...@googlemail.com> wrote:
> Hello,
>
> This patch - third of series - fixes vrp to handle bitwise one-bit
> precision typed operations.
> And it introduces a second - limitted to non-switch-statement range - vrp
> pass.
Err - please split this patch. I agree with Paolo, this 2nd
substitute_and_fold call is bogus. More comments inline.
>
> Bootstrapped and regression tested for all standard-languages (plus
> Ada and Obj-C++) on host x86_64-pc-linux-gnu.
>
> Ok for apply?
>
> Regards,
> Kai
>
> ChangeLog
>
> 2011-07-07 Kai Tietz <kti...@redhat.com>
>
> * tree-vrp.c (in_second_pass): New static variable.
> (extract_range_from_binary_expr): Add handling for
> BIT_IOR_EXPR, BIT_AND_EXPR, and BIT_NOT_EXPR.
> (register_edge_assert_for_1): Add handling for 1-bit
> BIT_IOR_EXPR and BIT_NOT_EXPR.
> (register_edge_assert_for): Add handling for 1-bit
> BIT_IOR_EXPR.
> (ssa_name_get_inner_ssa_name_p): New helper function.
> (ssa_name_get_cast_to_p): New helper function.
> (simplify_truth_ops_using_ranges): Handle prefixed
> cast instruction for result, and add support for one
> bit precision BIT_IOR_EXPR, BIT_AND_EXPR, BIT_XOR_EXPR,
> , and BIT_NOT_EXPR.
> (simplify_stmt_using_ranges): Add handling for one bit
> precision BIT_IOR_EXPR, BIT_AND_EXPR, BIT_XOR_EXPR,
> and BIT_NOT_EXPR.
> (vrp_finalize): Do substitute and fold pass a second
> time for vrp_stmt and preserve switch-edge simplification
> on second run.
> (simplify_switch_using_ranges): Preserve rerun of function
> in second pass.
>
> Index: gcc-head/gcc/tree-vrp.c
> ===================================================================
> --- gcc-head.orig/gcc/tree-vrp.c
> +++ gcc-head/gcc/tree-vrp.c
> @@ -74,6 +74,9 @@ struct value_range_d
>
> typedef struct value_range_d value_range_t;
>
> +/* This flag indicates that we are doing a second pass of VRP. */
> +static bool in_second_pass = false;
> +
> /* Set of SSA names found live during the RPO traversal of the function
> for still active basic-blocks. */
> static sbitmap *live;
> @@ -2232,6 +2235,7 @@ extract_range_from_binary_expr (value_ra
> some cases. */
> if (code != BIT_AND_EXPR
> && code != TRUTH_AND_EXPR
> + && code != BIT_IOR_EXPR
Huh? So how would VARYING | x ever produce something better
than VARYING?
> && code != TRUTH_OR_EXPR
> && code != TRUNC_DIV_EXPR
> && code != FLOOR_DIV_EXPR
> @@ -2291,6 +2295,8 @@ extract_range_from_binary_expr (value_ra
> else
> set_value_range_to_varying (vr);
> }
> + else if (code == BIT_IOR_EXPR)
> + set_value_range_to_varying (vr);
err - BIT_IOR_EXPR on pointers?
> else
> gcc_unreachable ();
>
> @@ -2300,11 +2306,13 @@ extract_range_from_binary_expr (value_ra
> /* For integer ranges, apply the operation to each end of the
> range and see what we end up with. */
> if (code == TRUTH_AND_EXPR
> - || code == TRUTH_OR_EXPR)
> + || code == TRUTH_OR_EXPR
> + || ((code == BIT_AND_EXPR || code == BIT_IOR_EXPR)
> + && TYPE_PRECISION (TREE_TYPE (op1)) == 1))
Rather than adding code to handle BIT_*_EXPR this patch should
transform the TRUTH_*_EXPR handling to appropriate BIT_*_EXPR
handling as we no longer have TRUTH_*_EXPR in our IL.
In fact I would say the existing BIT_*_EXPR handling should already
cover all the TRUTH_*_CASES, so this patch patches the wrong
spot if it is necessary at all.
> {
> /* If one of the operands is zero, we know that the whole
> expression evaluates zero. */
> - if (code == TRUTH_AND_EXPR
> + if ((code == TRUTH_AND_EXPR || code == BIT_AND_EXPR)
> && ((vr0.type == VR_RANGE
> && integer_zerop (vr0.min)
> && integer_zerop (vr0.max))
> @@ -2317,7 +2325,7 @@ extract_range_from_binary_expr (value_ra
> }
> /* If one of the operands is one, we know that the whole
> expression evaluates one. */
> - else if (code == TRUTH_OR_EXPR
> + else if ((code == TRUTH_OR_EXPR || code == BIT_IOR_EXPR)
> && ((vr0.type == VR_RANGE
> && integer_onep (vr0.min)
> && integer_onep (vr0.max))
> @@ -2809,7 +2817,7 @@ extract_range_from_unary_expr (value_ran
> cannot easily determine a resulting range. */
> if (code == FIX_TRUNC_EXPR
> || code == FLOAT_EXPR
> - || code == BIT_NOT_EXPR
> + || (code == BIT_NOT_EXPR && TYPE_PRECISION (type) != 1)
> || code == CONJ_EXPR)
> {
> /* We can still do constant propagation here. */
> @@ -3976,7 +3984,9 @@ build_assert_expr_for (tree cond, tree v
> tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
> assertion = gimple_build_assign (n, a);
> }
> - else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
> + else if (TREE_CODE (cond) == TRUTH_NOT_EXPR
> + || (TREE_CODE (cond) == BIT_NOT_EXPR
> + && TYPE_PRECISION (TREE_TYPE (cond)) == 1))
> {
> /* Given !V, build the assignment N = false. */
> tree op0 = TREE_OPERAND (cond, 0);
> @@ -4531,7 +4541,9 @@ register_edge_assert_for_1 (tree op, enu
> retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
> code, e, bsi);
> }
> - else if (gimple_assign_rhs_code (op_def) == TRUTH_NOT_EXPR)
> + else if (gimple_assign_rhs_code (op_def) == TRUTH_NOT_EXPR
> + || (gimple_assign_rhs_code (op_def) == BIT_NOT_EXPR
> + && TYPE_PRECISION (TREE_TYPE (op)) == 1))
> {
> /* Recurse, flipping CODE. */
> code = invert_tree_comparison (code, false);
> @@ -4617,6 +4629,9 @@ register_edge_assert_for (tree name, edg
>
> if (is_gimple_assign (def_stmt)
> && (gimple_assign_rhs_code (def_stmt) == TRUTH_OR_EXPR
> + || (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR
> + && INTEGRAL_TYPE_P (TREE_TYPE (name))
> + && TYPE_PRECISION (TREE_TYPE (name)) == 1)
> /* For BIT_IOR_EXPR only if NAME == 0 both operands have
> necessarily zero value. */
> || (comp_code == EQ_EXPR
> @@ -6747,19 +6762,96 @@ varying:
> return SSA_PROP_VARYING;
> }
>
> +/* Returns operand1 of ssa-name with SSA_NAME as code, Otherwise it
> + returns NULL_TREE. */
? Why would you want to look through a single copy?
> +static tree
> +ssa_name_get_inner_ssa_name_p (tree op)
> +{
> + gimple stmt;
> +
> + if (TREE_CODE (op) != SSA_NAME
> + || !is_gimple_assign (SSA_NAME_DEF_STMT (op)))
> + return NULL_TREE;
> + stmt = SSA_NAME_DEF_STMT (op);
> + if (gimple_assign_rhs_code (stmt) != SSA_NAME)
> + return NULL_TREE;
> + return gimple_assign_rhs1 (stmt);
> +}
> +
> +/* Returns operand of cast operation, if OP is a type-conversion. Otherwise
> + return NULL_TREE. */
> +static tree
> +ssa_name_get_cast_to_p (tree op)
> +{
> + gimple stmt;
> +
> + if (TREE_CODE (op) != SSA_NAME
> + || !is_gimple_assign (SSA_NAME_DEF_STMT (op)))
> + return NULL_TREE;
> + stmt = SSA_NAME_DEF_STMT (op);
> + if (!CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt)))
> + return NULL_TREE;
> + return gimple_assign_rhs1 (stmt);
> +}
> +
> /* Simplify boolean operations if the source is known
> to be already a boolean. */
> static bool
> simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
> {
> enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
> + gimple stmt2 = stmt;
> tree val = NULL;
> - tree op0, op1;
> + tree op0, op1, cop0, cop1;
> value_range_t *vr;
> bool sop = false;
> bool need_conversion;
> + location_t loc = gimple_location (stmt);
>
> op0 = gimple_assign_rhs1 (stmt);
> + op1 = NULL_TREE;
> +
> + /* Handle cases with prefixed type-cast. */
What cases? This code lacks comments.
> + if (CONVERT_EXPR_CODE_P (rhs_code)
So this simplifies conversions, not truth ops.
> + && INTEGRAL_TYPE_P (TREE_TYPE (op0))
> + && TREE_CODE (op0) == SSA_NAME
> + && is_gimple_assign (SSA_NAME_DEF_STMT (op0))
> + && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_lhs (stmt))))
> + {
> + stmt2 = SSA_NAME_DEF_STMT (op0);
> + op0 = gimple_assign_rhs1 (stmt2);
> + if (!INTEGRAL_TYPE_P (TREE_TYPE (op0)))
> + return false;
> + rhs_code = gimple_assign_rhs_code (stmt2);
> + if (rhs_code != BIT_NOT_EXPR && rhs_code != TRUTH_NOT_EXPR
> + && rhs_code != TRUTH_AND_EXPR && rhs_code != BIT_AND_EXPR
> + && rhs_code != TRUTH_OR_EXPR && rhs_code != BIT_IOR_EXPR
> + && rhs_code != TRUTH_XOR_EXPR && rhs_code != BIT_XOR_EXPR
> + && rhs_code != NE_EXPR && rhs_code != EQ_EXPR)
> + return false;
> + if (rhs_code == BIT_AND_EXPR || rhs_code == BIT_IOR_EXPR
> + || rhs_code == BIT_XOR_EXPR || rhs_code == TRUTH_AND_EXPR
> + || rhs_code == TRUTH_OR_EXPR || rhs_code == TRUTH_XOR_EXPR
> + || rhs_code == NE_EXPR || rhs_code == EQ_EXPR)
> + op1 = gimple_assign_rhs2 (stmt2);
> + if (gimple_has_location (stmt2))
> + loc = gimple_location (stmt2);
> + }
> + else if (CONVERT_EXPR_CODE_P (rhs_code))
> + return false;
That's funny control flow.
> + else if (rhs_code == BIT_AND_EXPR || rhs_code == BIT_IOR_EXPR
> + || rhs_code == BIT_XOR_EXPR || rhs_code == TRUTH_AND_EXPR
> + || rhs_code == TRUTH_OR_EXPR || rhs_code == TRUTH_XOR_EXPR
> + || rhs_code == NE_EXPR || rhs_code == EQ_EXPR)
> + op1 = gimple_assign_rhs2 (stmt);
> +
> + /* ~X is only equivalent of !X, if type-precision is one and X has
> + an integral type. */
> + if (rhs_code == BIT_NOT_EXPR
> + && (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
> + || TYPE_PRECISION (TREE_TYPE (op0)) != 1))
> + return false;
> +
> if (TYPE_PRECISION (TREE_TYPE (op0)) != 1)
> {
> if (TREE_CODE (op0) != SSA_NAME)
> @@ -6775,22 +6867,100 @@ simplify_truth_ops_using_ranges (gimple_
> return false;
> }
>
> - if (rhs_code == TRUTH_NOT_EXPR)
> + if (op1 && TREE_CODE (op1) != INTEGER_CST
> + && TYPE_PRECISION (TREE_TYPE (op1)) != 1)
> + {
> + vr = get_value_range (op1);
> + val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
> + if (!val || !integer_onep (val))
> + return false;
> +
> + val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
> + if (!val || !integer_onep (val))
> + return false;
> + }
> +
> + need_conversion =
> + !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt)),
> + TREE_TYPE (op0));
> +
> + /* As comparisons X != 0 getting folded by prior pass to (bool) X,
> + but X == 0 might be not folded for none boolean type of X
> + to (bool) (X ^ 1).
> + So for bitwise-binary operations we have three cases to handle:
> + a) ((bool) X) op ((bool) Y)
> + b) ((bool) X) op (Y == 0) OR (X == 0) op ((bool) Y)
> + c) (X == 0) op (Y == 0)
> + The later two cases can't be handled for now, as vr tables
> + would need to be adjusted. */
> + if (need_conversion
> + && (rhs_code == BIT_XOR_EXPR
> + || rhs_code == BIT_AND_EXPR
> + || rhs_code == BIT_IOR_EXPR)
> + && TREE_CODE (op1) == SSA_NAME && TREE_CODE (op0) == SSA_NAME)
> + {
> + cop0 = ssa_name_get_cast_to_p (op0);
> + cop1 = ssa_name_get_cast_to_p (op1);
> + if (!cop0 || !cop1)
> + /* We would need an new statment for cases b and c, and we can't
> + due vr table, so bail out. */
> + return false;
> +
> + if (!INTEGRAL_TYPE_P (TREE_TYPE (cop0))
> + || !types_compatible_p (TREE_TYPE (cop0), TREE_TYPE (cop1)))
> + return false;
> + need_conversion =
> + !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt)),
> + TREE_TYPE (cop0));
> + if (need_conversion)
> + return false;
> + op0 = cop0;
> + op1 = cop1;
> +
> + /* We need to re-check if value ranges for new operands
> + for 1-bit precision/range. */
> + if (TYPE_PRECISION (TREE_TYPE (op0)) != 1)
> + {
> + if (TREE_CODE (op0) != SSA_NAME)
> + return false;
> + vr = get_value_range (op0);
> +
> + val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
> &sop);
> + if (!val || !integer_onep (val))
> + return false;
> +
> + val = compare_range_with_value (LE_EXPR, vr, integer_one_node,
> &sop);
> + if (!val || !integer_onep (val))
> + return false;
> + }
> +
> + if (op1 && TYPE_PRECISION (TREE_TYPE (op1)) != 1)
> + {
> + vr = get_value_range (op1);
> + val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
> &sop);
> + if (!val || !integer_onep (val))
> + return false;
> +
> + val = compare_range_with_value (LE_EXPR, vr, integer_one_node,
> &sop);
> + if (!val || !integer_onep (val))
> + return false;
> + }
> + }
> + else if (rhs_code == TRUTH_NOT_EXPR || rhs_code == BIT_NOT_EXPR)
> {
> rhs_code = NE_EXPR;
> op1 = build_int_cst (TREE_TYPE (op0), 1);
> }
> else
> {
> - op1 = gimple_assign_rhs2 (stmt);
> -
> /* Reduce number of cases to handle. */
> if (is_gimple_min_invariant (op1))
> {
> /* Exclude anything that should have been already folded. */
> if (rhs_code != EQ_EXPR
> && rhs_code != NE_EXPR
> - && rhs_code != TRUTH_XOR_EXPR)
> + && rhs_code != TRUTH_XOR_EXPR
> + && rhs_code != BIT_XOR_EXPR)
> return false;
>
> if (!integer_zerop (op1)
> @@ -6810,18 +6980,6 @@ simplify_truth_ops_using_ranges (gimple_
> /* Punt on A == B as there is no BIT_XNOR_EXPR. */
> if (rhs_code == EQ_EXPR)
> return false;
> -
> - if (TYPE_PRECISION (TREE_TYPE (op1)) != 1)
> - {
> - vr = get_value_range (op1);
> - val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
> &sop);
> - if (!val || !integer_onep (val))
> - return false;
> -
> - val = compare_range_with_value (LE_EXPR, vr, integer_one_node,
> &sop);
> - if (!val || !integer_onep (val))
> - return false;
> - }
> }
> }
>
> @@ -6838,7 +6996,8 @@ simplify_truth_ops_using_ranges (gimple_
> warning_at (location, OPT_Wstrict_overflow,
> _("assuming signed overflow does not occur when "
> "simplifying && or || to & or |"));
> - else
> + else if (rhs_code != BIT_AND_EXPR && rhs_code != BIT_IOR_EXPR
> + && rhs_code != BIT_XOR_EXPR)
> warning_at (location, OPT_Wstrict_overflow,
> _("assuming signed overflow does not occur when "
> "simplifying ==, != or ! to identity or ^"));
> @@ -6859,16 +7018,21 @@ simplify_truth_ops_using_ranges (gimple_
> case TRUTH_AND_EXPR:
> rhs_code = BIT_AND_EXPR;
> break;
> + case BIT_AND_EXPR:
> + break;
> case TRUTH_OR_EXPR:
> rhs_code = BIT_IOR_EXPR;
> + case BIT_IOR_EXPR:
> break;
> case TRUTH_XOR_EXPR:
> + case BIT_XOR_EXPR:
> case NE_EXPR:
> if (integer_zerop (op1))
> {
> gimple_assign_set_rhs_with_ops (gsi,
> need_conversion ? NOP_EXPR :
> SSA_NAME,
> op0, NULL);
> + gimple_set_location (stmt, loc);
> update_stmt (gsi_stmt (*gsi));
> return true;
> }
> @@ -6879,10 +7043,20 @@ simplify_truth_ops_using_ranges (gimple_
> gcc_unreachable ();
> }
>
> + /* We can't insert here new expression as otherwise
> + tracked vr tables getting out of bounds. */
> if (need_conversion)
> return false;
>
> + /* Reduce here SSA_NAME -> SSA_NAME. */
> + while ((cop0 = ssa_name_get_inner_ssa_name_p (op0)) != NULL_TREE)
> + op0 = cop0;
> +
> + while ((cop1 = ssa_name_get_inner_ssa_name_p (op1)) != NULL_TREE)
> + op1 = cop1;
> +
> gimple_assign_set_rhs_with_ops (gsi, rhs_code, op0, op1);
> + gimple_set_location (stmt, loc);
> update_stmt (gsi_stmt (*gsi));
> return true;
> }
> @@ -7263,6 +7437,9 @@ simplify_switch_using_ranges (gimple stm
> tree vec2;
> switch_update su;
>
> + if (in_second_pass)
> + return false;
> +
> if (TREE_CODE (op) == SSA_NAME)
> {
> vr = get_value_range (op);
> @@ -7390,6 +7567,7 @@ simplify_stmt_using_ranges (gimple_stmt_
> {
> case EQ_EXPR:
> case NE_EXPR:
> + case BIT_NOT_EXPR:
> case TRUTH_NOT_EXPR:
> case TRUTH_AND_EXPR:
> case TRUTH_OR_EXPR:
> @@ -7425,13 +7603,21 @@ simplify_stmt_using_ranges (gimple_stmt_
> if all the bits being cleared are already cleared or
> all the bits being set are already set. */
> if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
> - return simplify_bit_ops_using_ranges (gsi, stmt);
> + {
> + if (simplify_truth_ops_using_ranges (gsi, stmt))
> + return true;
> + return simplify_bit_ops_using_ranges (gsi, stmt);
> + }
> break;
>
> CASE_CONVERT:
> if (TREE_CODE (rhs1) == SSA_NAME
> && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
> - return simplify_conversion_using_ranges (stmt);
> + {
> + if (simplify_truth_ops_using_ranges (gsi, stmt))
> + return true;
> + return simplify_conversion_using_ranges (stmt);
> + }
> break;
>
> default:
> @@ -7685,8 +7870,16 @@ vrp_finalize (void)
> fprintf (dump_file, "\n");
> }
>
> + /* We redo folding here one time for allowing to inspect more
> + complex reductions. */
> + substitute_and_fold (op_with_constant_singleton_value_range,
> + vrp_fold_stmt, false);
> + /* We need to mark this second pass to avoid re-entering of same
> + edges for switch statments. */
> + in_second_pass = true;
> substitute_and_fold (op_with_constant_singleton_value_range,
> vrp_fold_stmt, false);
> + in_second_pass = false;
If at all you only want to re-call vrp_fold_stmt on all stmts in the
function, not do a full-blown substitute_and_fold.
Richard.
> if (warn_array_bounds)
> check_all_array_refs ();
>
