On Fri, Oct 14, 2011 at 9:43 PM, Kai Tietz <ktiet...@googlemail.com> wrote: > Hello, > > So I committed the gimplify patch separate. And here is the remaining > fold-const patch. > The important tests here are in gcc.dg/tree-ssa/builtin-expect[1-4].c, which > cover the one special-case for branching. Also tree-ssa/20040204-1.c covers > tests for branching code (on targets having high-engough BRANCH_COST and no > special-casing - like MIPS, S/390, and AVR. > > ChangeLog > > 2011-10-14 Kai Tietz <kti...@redhat.com> > > * fold-const.c (simple_operand_p_2): New function. > (fold_truthop): Rename to > (fold_truth_andor_1): function name. > Additionally remove branching creation for logical and/or. > (fold_truth_andor): Handle branching creation for logical and/or here. > > Bootstrapped and regression-tested for all languages plus Ada and > Obj-C++ on x86_64-pc-linux-gnu. > Ok for apply?
Ok with ... > Regards, > Kai > > Index: gcc/gcc/fold-const.c > =================================================================== > --- gcc.orig/gcc/fold-const.c > +++ gcc/gcc/fold-const.c > @@ -112,13 +112,13 @@ static tree decode_field_reference (loca > static int all_ones_mask_p (const_tree, int); > static tree sign_bit_p (tree, const_tree); > static int simple_operand_p (const_tree); > +static bool simple_operand_p_2 (tree); > static tree range_binop (enum tree_code, tree, tree, int, tree, int); > static tree range_predecessor (tree); > static tree range_successor (tree); > static tree fold_range_test (location_t, enum tree_code, tree, tree, tree); > static tree fold_cond_expr_with_comparison (location_t, tree, tree, > tree, tree); > static tree unextend (tree, int, int, tree); > -static tree fold_truthop (location_t, enum tree_code, tree, tree, tree); > static tree optimize_minmax_comparison (location_t, enum tree_code, > tree, tree, tree); > static tree extract_muldiv (tree, tree, enum tree_code, tree, bool *); > @@ -3500,7 +3500,7 @@ optimize_bit_field_compare (location_t l > return lhs; > } > > -/* Subroutine for fold_truthop: decode a field reference. > +/* Subroutine for fold_truth_andor_1: decode a field reference. > > If EXP is a comparison reference, we return the innermost reference. > > @@ -3668,7 +3668,7 @@ sign_bit_p (tree exp, const_tree val) > return NULL_TREE; > } > > -/* Subroutine for fold_truthop: determine if an operand is simple enough > +/* Subroutine for fold_truth_andor_1: determine if an operand is simple > enough > to be evaluated unconditionally. */ > > static int > @@ -3678,7 +3678,7 @@ simple_operand_p (const_tree exp) > STRIP_NOPS (exp); > > return (CONSTANT_CLASS_P (exp) > - || TREE_CODE (exp) == SSA_NAME > + || TREE_CODE (exp) == SSA_NAME > || (DECL_P (exp) > && ! TREE_ADDRESSABLE (exp) > && ! TREE_THIS_VOLATILE (exp) > @@ -3692,6 +3692,46 @@ simple_operand_p (const_tree exp) > registers aren't expensive. */ > && (! TREE_STATIC (exp) || DECL_REGISTER (exp)))); > } > + > +/* Subroutine for fold_truth_andor: determine if an operand is simple enough > + to be evaluated unconditionally. > + I addition to simple_operand_p, we assume that comparisons and logic-not > + operations are simple, if their operands are simple, too. */ > + > +static bool > +simple_operand_p_2 (tree exp) > +{ > + enum tree_code code; > + > + /* Strip any conversions that don't change the machine mode. */ > + STRIP_NOPS (exp); > + > + code = TREE_CODE (exp); > + > + if (TREE_CODE_CLASS (code) == tcc_comparison) > + return (!tree_could_trap_p (exp) > + && simple_operand_p_2 (TREE_OPERAND (exp, 0)) > + && simple_operand_p_2 (TREE_OPERAND (exp, 1))); recurse with simple_operand_p. > + > + if (TREE_SIDE_EFFECTS (exp) > + || tree_could_trap_p (exp)) Move this check before the tcc_comparison check and remove the then redundant tree_could_trap_p check there. > + return false; > + > + switch (code) > + { > + case SSA_NAME: > + return true; Do not handle here, it's handled in simple_operand_p. > + case TRUTH_NOT_EXPR: > + return simple_operand_p_2 (TREE_OPERAND (exp, 0)); > + case BIT_NOT_EXPR: > + if (TREE_CODE (TREE_TYPE (exp)) != BOOLEAN_TYPE) > + return false; Remove the BIT_NOT_EXPR handling. Thus, simply change this switch to if (code == TRUTH_NOT_EXPR) return simple_operand_p_2 (TREE_OPERAND (exp, 0)); return simple_operand_p (exp); > + return simple_operand_p_2 (TREE_OPERAND (exp, 0)); > + default: > + return simple_operand_p (exp); > + } > +} > + > > /* The following functions are subroutines to fold_range_test and allow it to > try to change a logical combination of comparisons into a range test. > @@ -4888,7 +4928,7 @@ fold_range_test (location_t loc, enum tr > return 0; > } > > -/* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P > +/* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P > bit value. Arrange things so the extra bits will be set to zero if and > only if C is signed-extended to its full width. If MASK is nonzero, > it is an INTEGER_CST that should be AND'ed with the extra bits. */ > @@ -5025,8 +5065,8 @@ merge_truthop_with_opposite_arm (locatio > We return the simplified tree or 0 if no optimization is possible. */ > > static tree > -fold_truthop (location_t loc, enum tree_code code, tree truth_type, > - tree lhs, tree rhs) > +fold_truth_andor_1 (location_t loc, enum tree_code code, tree truth_type, > + tree lhs, tree rhs) > { > /* If this is the "or" of two comparisons, we can do something if > the comparisons are NE_EXPR. If this is the "and", we can do something > @@ -5054,8 +5094,6 @@ fold_truthop (location_t loc, enum tree_ > tree lntype, rntype, result; > HOST_WIDE_INT first_bit, end_bit; > int volatilep; > - tree orig_lhs = lhs, orig_rhs = rhs; > - enum tree_code orig_code = code; > > /* Start by getting the comparison codes. Fail if anything is volatile. > If one operand is a BIT_AND_EXPR with the constant one, treat it as if > @@ -5119,8 +5157,7 @@ fold_truthop (location_t loc, enum tree_ > /* If the RHS can be evaluated unconditionally and its operands are > simple, it wins to evaluate the RHS unconditionally on machines > with expensive branches. In this case, this isn't a comparison > - that can be merged. Avoid doing this if the RHS is a floating-point > - comparison since those can trap. */ > + that can be merged. */ > > if (BRANCH_COST (optimize_function_for_speed_p (cfun), > false) >= 2 > @@ -5149,13 +5186,6 @@ fold_truthop (location_t loc, enum tree_ > build2 (BIT_IOR_EXPR, TREE_TYPE (ll_arg), > ll_arg, rl_arg), > build_int_cst (TREE_TYPE (ll_arg), 0)); > - > - if (LOGICAL_OP_NON_SHORT_CIRCUIT) > - { > - if (code != orig_code || lhs != orig_lhs || rhs != orig_rhs) > - return build2_loc (loc, code, truth_type, lhs, rhs); > - return NULL_TREE; > - } > } > > /* See if the comparisons can be merged. Then get all the parameters for > @@ -8380,13 +8410,49 @@ fold_truth_andor (location_t loc, enum t > lhs is another similar operation, try to merge its rhs with our > rhs. Then try to merge our lhs and rhs. */ > if (TREE_CODE (arg0) == code > - && 0 != (tem = fold_truthop (loc, code, type, > - TREE_OPERAND (arg0, 1), arg1))) > + && 0 != (tem = fold_truth_andor_1 (loc, code, type, > + TREE_OPERAND (arg0, 1), arg1))) > return fold_build2_loc (loc, code, type, TREE_OPERAND (arg0, 0), tem); > > - if ((tem = fold_truthop (loc, code, type, arg0, arg1)) != 0) > + if ((tem = fold_truth_andor_1 (loc, code, type, arg0, arg1)) != 0) > return tem; > > + if ((code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR) > + && (BRANCH_COST (optimize_function_for_speed_p (cfun), > + false) >= 2) > + && LOGICAL_OP_NON_SHORT_CIRCUIT > + && simple_operand_p_2 (arg1)) > + { > + enum tree_code ncode = (code == TRUTH_ANDIF_EXPR ? TRUTH_AND_EXPR > + : TRUTH_OR_EXPR); > + > + /* Transform ((A AND-IF B) AND-IF C) into (A AND-IF (B AND C)), > + or ((A OR-IF B) OR-IF C) into (A OR-IF (B OR C)) > + We don't want to pack more than two leafs to a non-IF AND/OR > + expression. > + If tree-code of left-hand operand isn't an AND/OR-IF code and not > + equal to CODE, then we don't want to add right-hand operand. > + If the inner right-hand side of left-hand operand has side-effects, > + or isn't simple, then we can't add to it, as otherwise we might > + destroy if-sequence. */ > + if (TREE_CODE (arg0) == code > + /* Needed for sequence points to handle trappings, and > + side-effects. */ > + && simple_operand_p_2 (TREE_OPERAND (arg0, 1))) > + { > + tem = fold_build2_loc (loc, ncode, type, TREE_OPERAND (arg0, 1), > + arg1); > + return fold_build2_loc (loc, code, type, TREE_OPERAND (arg0, 0), > + tem); > + } I see you insist on this change. Let me explain again. You do this for ((A AND-IF B) AND-IF C) but you don't do this for ((A AND-IF B) AND C). Why? That is what doesn't make sense ot me. Thus omit this hunk. Ok with the above changes. Thanks, Richard. > + /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B) > + into (A OR B). > + For sequence point consistancy, we need to check for trapping, and > + side-effects. */ > + else if (simple_operand_p_2 (arg0)) > + return fold_build2_loc (loc, ncode, type, arg0, arg1); > + } > + > return NULL_TREE; > } >