On Fri, Apr 29, 2016 at 7:36 PM, Marc Glisse <marc.gli...@inria.fr> wrote:
> On Fri, 29 Apr 2016, Richard Biener wrote:
>
>> Another option is to move the enum declaration from flag-types.h to
>> coretypes.h. I think I like that best.
>
>
> This works.
Ok.
Thanks,
Richard.
> 2016-05-02 Marc Glisse <marc.gli...@inria.fr>
>
> gcc/
> * flag-types.h (enum warn_strict_overflow_code): Move ...
> * coretypes.h: ... here.
> * fold-const.h (fold_overflow_warning): Declare.
> * fold-const.c (fold_overflow_warning): Make non-static.
> (fold_comparison): Move the transformation of X +- C1 CMP C2
> into X CMP C2 -+ C1 ...
> * match.pd: ... here.
> * gimple-fold.c (fold_stmt_1): Protect with
>
> fold_defer_overflow_warnings.
>
> gcc/testsuite/
> * gcc.dg/tree-ssa/20040305-1.c: Adjust.
>
> --
> Marc Glisse
>
> Index: gcc/coretypes.h
> ===================================================================
> --- gcc/coretypes.h (revision 235644)
> +++ gcc/coretypes.h (working copy)
> @@ -215,20 +215,44 @@ enum optimization_type {
> /* Possible initialization status of a variable. When requested
> by the user, this information is tracked and recorded in the DWARF
> debug information, along with the variable's location. */
> enum var_init_status
> {
> VAR_INIT_STATUS_UNKNOWN,
> VAR_INIT_STATUS_UNINITIALIZED,
> VAR_INIT_STATUS_INITIALIZED
> };
>
> +/* Names for the different levels of -Wstrict-overflow=N. The numeric
> + values here correspond to N. */
> +enum warn_strict_overflow_code
> +{
> + /* Overflow warning that should be issued with -Wall: a questionable
> + construct that is easy to avoid even when using macros. Example:
> + folding (x + CONSTANT > x) to 1. */
> + WARN_STRICT_OVERFLOW_ALL = 1,
> + /* Overflow warning about folding a comparison to a constant because
> + of undefined signed overflow, other than cases covered by
> + WARN_STRICT_OVERFLOW_ALL. Example: folding (abs (x) >= 0) to 1
> + (this is false when x == INT_MIN). */
> + WARN_STRICT_OVERFLOW_CONDITIONAL = 2,
> + /* Overflow warning about changes to comparisons other than folding
> + them to a constant. Example: folding (x + 1 > 1) to (x > 0). */
> + WARN_STRICT_OVERFLOW_COMPARISON = 3,
> + /* Overflow warnings not covered by the above cases. Example:
> + folding ((x * 10) / 5) to (x * 2). */
> + WARN_STRICT_OVERFLOW_MISC = 4,
> + /* Overflow warnings about reducing magnitude of constants in
> + comparison. Example: folding (x + 2 > y) to (x + 1 >= y). */
> + WARN_STRICT_OVERFLOW_MAGNITUDE = 5
> +};
> +
> /* The type of an alias set. Code currently assumes that variables of
> this type can take the values 0 (the alias set which aliases
> everything) and -1 (sometimes indicating that the alias set is
> unknown, sometimes indicating a memory barrier) and -2 (indicating
> that the alias set should be set to a unique value but has not been
> set yet). */
> typedef int alias_set_type;
>
> struct edge_def;
> typedef struct edge_def *edge;
> Index: gcc/flag-types.h
> ===================================================================
> --- gcc/flag-types.h (revision 235644)
> +++ gcc/flag-types.h (working copy)
> @@ -171,44 +171,20 @@ enum stack_check_type
> /* Check the stack and rely on the target configuration files to
> check the static frame of functions, i.e. use the generic
> mechanism only for dynamic stack allocations. */
> STATIC_BUILTIN_STACK_CHECK,
>
> /* Check the stack and entirely rely on the target configuration
> files, i.e. do not use the generic mechanism at all. */
> FULL_BUILTIN_STACK_CHECK
> };
>
> -/* Names for the different levels of -Wstrict-overflow=N. The numeric
> - values here correspond to N. */
> -enum warn_strict_overflow_code
> -{
> - /* Overflow warning that should be issued with -Wall: a questionable
> - construct that is easy to avoid even when using macros. Example:
> - folding (x + CONSTANT > x) to 1. */
> - WARN_STRICT_OVERFLOW_ALL = 1,
> - /* Overflow warning about folding a comparison to a constant because
> - of undefined signed overflow, other than cases covered by
> - WARN_STRICT_OVERFLOW_ALL. Example: folding (abs (x) >= 0) to 1
> - (this is false when x == INT_MIN). */
> - WARN_STRICT_OVERFLOW_CONDITIONAL = 2,
> - /* Overflow warning about changes to comparisons other than folding
> - them to a constant. Example: folding (x + 1 > 1) to (x > 0). */
> - WARN_STRICT_OVERFLOW_COMPARISON = 3,
> - /* Overflow warnings not covered by the above cases. Example:
> - folding ((x * 10) / 5) to (x * 2). */
> - WARN_STRICT_OVERFLOW_MISC = 4,
> - /* Overflow warnings about reducing magnitude of constants in
> - comparison. Example: folding (x + 2 > y) to (x + 1 >= y). */
> - WARN_STRICT_OVERFLOW_MAGNITUDE = 5
> -};
> -
> /* Floating-point contraction mode. */
> enum fp_contract_mode {
> FP_CONTRACT_OFF = 0,
> FP_CONTRACT_ON = 1,
> FP_CONTRACT_FAST = 2
> };
>
> /* Scalar storage order kind. */
> enum scalar_storage_order_kind {
> SSO_NATIVE = 0,
> Index: gcc/fold-const.c
> ===================================================================
> --- gcc/fold-const.c (revision 235644)
> +++ gcc/fold-const.c (working copy)
> @@ -290,21 +290,21 @@ fold_undefer_and_ignore_overflow_warning
>
> bool
> fold_deferring_overflow_warnings_p (void)
> {
> return fold_deferring_overflow_warnings > 0;
> }
>
> /* This is called when we fold something based on the fact that signed
> overflow is undefined. */
>
> -static void
> +void
> fold_overflow_warning (const char* gmsgid, enum warn_strict_overflow_code
> wc)
> {
> if (fold_deferring_overflow_warnings > 0)
> {
> if (fold_deferred_overflow_warning == NULL
> || wc < fold_deferred_overflow_code)
> {
> fold_deferred_overflow_warning = gmsgid;
> fold_deferred_overflow_code = wc;
> }
> @@ -8388,89 +8388,20 @@ fold_comparison (location_t loc, enum tr
> {
> const bool equality_code = (code == EQ_EXPR || code == NE_EXPR);
> tree arg0, arg1, tem;
>
> arg0 = op0;
> arg1 = op1;
>
> STRIP_SIGN_NOPS (arg0);
> STRIP_SIGN_NOPS (arg1);
>
> - /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 -+ C1.
> */
> - if ((TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
> - && (equality_code
> - || (ANY_INTEGRAL_TYPE_P (TREE_TYPE (arg0))
> - && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (arg0))))
> - && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
> - && !TREE_OVERFLOW (TREE_OPERAND (arg0, 1))
> - && TREE_CODE (arg1) == INTEGER_CST
> - && !TREE_OVERFLOW (arg1))
> - {
> - const enum tree_code
> - reverse_op = TREE_CODE (arg0) == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR;
> - tree const1 = TREE_OPERAND (arg0, 1);
> - tree const2 = fold_convert_loc (loc, TREE_TYPE (const1), arg1);
> - tree variable = TREE_OPERAND (arg0, 0);
> - tree new_const = int_const_binop (reverse_op, const2, const1);
> -
> - /* If the constant operation overflowed this can be
> - simplified as a comparison against INT_MAX/INT_MIN. */
> - if (TREE_OVERFLOW (new_const)
> - && !TYPE_OVERFLOW_WRAPS (TREE_TYPE (arg0)))
> - {
> - int const1_sgn = tree_int_cst_sgn (const1);
> - enum tree_code code2 = code;
> -
> - /* Get the sign of the constant on the lhs if the
> - operation were VARIABLE + CONST1. */
> - if (TREE_CODE (arg0) == MINUS_EXPR)
> - const1_sgn = -const1_sgn;
> -
> - /* The sign of the constant determines if we overflowed
> - INT_MAX (const1_sgn == -1) or INT_MIN (const1_sgn == 1).
> - Canonicalize to the INT_MIN overflow by swapping the comparison
> - if necessary. */
> - if (const1_sgn == -1)
> - code2 = swap_tree_comparison (code);
> -
> - /* We now can look at the canonicalized case
> - VARIABLE + 1 CODE2 INT_MIN
> - and decide on the result. */
> - switch (code2)
> - {
> - case EQ_EXPR:
> - case LT_EXPR:
> - case LE_EXPR:
> - return
> - omit_one_operand_loc (loc, type, boolean_false_node,
> variable);
> -
> - case NE_EXPR:
> - case GE_EXPR:
> - case GT_EXPR:
> - return
> - omit_one_operand_loc (loc, type, boolean_true_node,
> variable);
> -
> - default:
> - gcc_unreachable ();
> - }
> - }
> - else
> - {
> - if (!equality_code)
> - fold_overflow_warning ("assuming signed overflow does not occur
> "
> - "when changing X +- C1 cmp C2 to "
> - "X cmp C2 -+ C1",
> - WARN_STRICT_OVERFLOW_COMPARISON);
> - return fold_build2_loc (loc, code, type, variable, new_const);
> - }
> - }
> -
> /* For comparisons of pointers we can decompose it to a compile time
> comparison of the base objects and the offsets into the object.
> This requires at least one operand being an ADDR_EXPR or a
> POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
> if (POINTER_TYPE_P (TREE_TYPE (arg0))
> && (TREE_CODE (arg0) == ADDR_EXPR
> || TREE_CODE (arg1) == ADDR_EXPR
> || TREE_CODE (arg0) == POINTER_PLUS_EXPR
> || TREE_CODE (arg1) == POINTER_PLUS_EXPR))
> {
> Index: gcc/fold-const.h
> ===================================================================
> --- gcc/fold-const.h (revision 235644)
> +++ gcc/fold-const.h (working copy)
> @@ -79,20 +79,21 @@ extern bool fold_convertible_p (const_tr
> fold_convert_loc (UNKNOWN_LOCATION, T1, T2)
> extern tree fold_convert_loc (location_t, tree, tree);
> extern tree fold_single_bit_test (location_t, enum tree_code, tree, tree,
> tree);
> extern tree fold_ignored_result (tree);
> extern tree fold_abs_const (tree, tree);
> extern tree fold_indirect_ref_1 (location_t, tree, tree);
> extern void fold_defer_overflow_warnings (void);
> extern void fold_undefer_overflow_warnings (bool, const gimple *, int);
> extern void fold_undefer_and_ignore_overflow_warnings (void);
> extern bool fold_deferring_overflow_warnings_p (void);
> +extern void fold_overflow_warning (const char*, enum
> warn_strict_overflow_code);
> extern int operand_equal_p (const_tree, const_tree, unsigned int);
> extern int multiple_of_p (tree, const_tree, const_tree);
> #define omit_one_operand(T1,T2,T3)\
> omit_one_operand_loc (UNKNOWN_LOCATION, T1, T2, T3)
> extern tree omit_one_operand_loc (location_t, tree, tree, tree);
> #define omit_two_operands(T1,T2,T3,T4)\
> omit_two_operands_loc (UNKNOWN_LOCATION, T1, T2, T3, T4)
> extern tree omit_two_operands_loc (location_t, tree, tree, tree, tree);
> #define invert_truthvalue(T)\
> invert_truthvalue_loc (UNKNOWN_LOCATION, T)
> Index: gcc/gimple-fold.c
> ===================================================================
> --- gcc/gimple-fold.c (revision 235644)
> +++ gcc/gimple-fold.c (working copy)
> @@ -3518,21 +3518,23 @@ maybe_canonicalize_mem_ref_addr (tree *t
> }
>
> /* Worker for both fold_stmt and fold_stmt_inplace. The INPLACE argument
> distinguishes both cases. */
>
> static bool
> fold_stmt_1 (gimple_stmt_iterator *gsi, bool inplace, tree (*valueize)
> (tree))
> {
> bool changed = false;
> gimple *stmt = gsi_stmt (*gsi);
> + bool nowarning = gimple_no_warning_p (stmt);
> unsigned i;
> + fold_defer_overflow_warnings ();
>
> /* First do required canonicalization of [TARGET_]MEM_REF addresses
> after propagation.
> ??? This shouldn't be done in generic folding but in the
> propagation helpers which also know whether an address was
> propagated.
> Also canonicalize operand order. */
> switch (gimple_code (stmt))
> {
> case GIMPLE_ASSIGN:
> @@ -3811,20 +3813,21 @@ fold_stmt_1 (gimple_stmt_iterator *gsi,
> {
> tree new_lhs = maybe_fold_reference (lhs, true);
> if (new_lhs)
> {
> gimple_set_lhs (stmt, new_lhs);
> changed = true;
> }
> }
> }
>
> + fold_undefer_overflow_warnings (changed && !nowarning, stmt, 0);
> return changed;
> }
>
> /* Valueziation callback that ends up not following SSA edges. */
>
> tree
> no_follow_ssa_edges (tree)
> {
> return NULL_TREE;
> }
> Index: gcc/match.pd
> ===================================================================
> --- gcc/match.pd (revision 235644)
> +++ gcc/match.pd (working copy)
> @@ -3179,10 +3179,54 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> (simplify
> /* signbit(x) -> 0 if x is nonnegative. */
> (SIGNBIT tree_expr_nonnegative_p@0)
> { integer_zero_node; })
>
> (simplify
> /* signbit(x) -> x<0 if x doesn't have signed zeros. */
> (SIGNBIT @0)
> (if (!HONOR_SIGNED_ZEROS (@0))
> (convert (lt @0 { build_real (TREE_TYPE (@0), dconst0); }))))
> +
> +/* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 -+ C1. */
> +(for cmp (eq ne)
> + (for op (plus minus)
> + rop (minus plus)
> + (simplify
> + (cmp (op@3 @0 INTEGER_CST@1) INTEGER_CST@2)
> + (if (!TREE_OVERFLOW (@1) && !TREE_OVERFLOW (@2)
> + && !TYPE_OVERFLOW_SANITIZED (TREE_TYPE (@0))
> + && !TYPE_OVERFLOW_TRAPS (TREE_TYPE (@0))
> + && !TYPE_SATURATING (TREE_TYPE (@0)))
> + (with { tree res = int_const_binop (rop, @2, @1); }
> + (if (TREE_OVERFLOW (res))
> + { constant_boolean_node (cmp == NE_EXPR, type); }
> + (if (single_use (@3))
> + (cmp @0 { res; }))))))))
> +(for cmp (lt le gt ge)
> + (for op (plus minus)
> + rop (minus plus)
> + (simplify
> + (cmp (op@3 @0 INTEGER_CST@1) INTEGER_CST@2)
> + (if (!TREE_OVERFLOW (@1) && !TREE_OVERFLOW (@2)
> + && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@0)))
> + (with { tree res = int_const_binop (rop, @2, @1); }
> + (if (TREE_OVERFLOW (res))
> + {
> + fold_overflow_warning (("assuming signed overflow does not occur "
> + "when simplifying conditional to constant"),
> + WARN_STRICT_OVERFLOW_CONDITIONAL);
> + bool less = cmp == LE_EXPR || cmp == LT_EXPR;
> + /* wi::ges_p (@2, 0) should be sufficient for a signed type. */
> + bool ovf_high = wi::lt_p (@1, 0, TYPE_SIGN (TREE_TYPE (@1)))
> + != (op == MINUS_EXPR);
> + constant_boolean_node (less == ovf_high, type);
> + }
> + (if (single_use (@3))
> + (with
> + {
> + fold_overflow_warning (("assuming signed overflow does not occur "
> + "when changing X +- C1 cmp C2 to "
> + "X cmp C2 -+ C1"),
> + WARN_STRICT_OVERFLOW_COMPARISON);
> + }
> + (cmp @0 { res; })))))))))
> Index: gcc/testsuite/gcc.dg/tree-ssa/20040305-1.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/tree-ssa/20040305-1.c (revision 235644)
> +++ gcc/testsuite/gcc.dg/tree-ssa/20040305-1.c (working copy)
> @@ -16,15 +16,15 @@ void foo(int edx, int eax)
> }
> if (eax == 100)
> {
> if (-- edx == 0)
> afred[0] = 2;
> }
> }
>
>
> /* Verify that we did a forward propagation. */
> -/* { dg-final { scan-tree-dump-times "Replaced" 1 "forwprop1"} } */
> +/* { dg-final { scan-tree-dump-times "gimple_simplified" 1 "forwprop1"} }
> */
>
> /* After cddce we should have two IF statements remaining as the other
> two tests can be threaded. */
> /* { dg-final { scan-tree-dump-times "if " 2 "cddce2"} } */
>
