Ping?
2012/4/5 Kai Tietz <ktiet...@googlemail.com>:
> Hello,
>
> this patch adds some basic folding capabilities to fold-const for
> equal and none-equal comparisons
> on integer typed argument.
>
> ChangeLog
>
> 2012-04-05 Kai Tietz <kti...@redhat.com>
>
> * fold-const.c (fold_comparison_1): New
> function.
> (fold_comparison): Use fold_comparison_1.
>
> 2012-04-05 Kai Tietz <kti...@redhat.com>
>
> * gcc.dg/fold-compare-1.c: Adjust matching rule
> for a == b without argument swap.
> * gcc.dg/fold-compare-7.c: New test.
>
> Regession tested for x86_64-unknown-linux-gnu for all languages
> (including Ada and Obj-C++). Ok for apply?
>
> Regards,
> Kai
>
> Index: gcc/gcc/fold-const.c
> ===================================================================
> --- gcc.orig/gcc/fold-const.c
> +++ gcc/gcc/fold-const.c
> @@ -8739,6 +8739,241 @@ pointer_may_wrap_p (tree base, tree offs
> return total_low > (unsigned HOST_WIDE_INT) size;
> }
>
> +/* Sub-routine of fold_comparison. Folding of EQ_EXPR/NE_EXPR
> + comparisons with integral typed arguments. */
> +
> +static tree
> +fold_comparison_1 (location_t loc, enum tree_code code, tree type,
> + tree arg0, tree arg1)
> +{
> + enum tree_code c1, c2;
> + tree optype, op0, op1, opr0, opr1, tem;
> +
> + if (code != NE_EXPR && code != EQ_EXPR)
> + return NULL_TREE;
> +
> + optype = TREE_TYPE (arg0);
> + if (!INTEGRAL_TYPE_P (optype))
> + return NULL_TREE;
> +
> + c1 = TREE_CODE (arg0);
> + c2 = TREE_CODE (arg1);
> +
> + /* Integer constant is on right-hand side. */
> + if (c1 == INTEGER_CST
> + && c2 != c1)
> + return fold_build2_loc (loc, code, type, arg1, arg0);
> +
> + if (!TREE_SIDE_EFFECTS (arg0)
> + && operand_equal_p (arg0, arg1, 0))
> + {
> + if (code == EQ_EXPR)
> + return build_one_cst (type);
> + return build_zero_cst (type);
> + }
> +
> +
> + if (c1 == NEGATE_EXPR)
> + {
> + op0 = TREE_OPERAND (arg0, 0);
> + /* -X ==/!= -Y -> X ==/!= Y. */
> + if (c2 == c1)
> + return fold_build2_loc (loc, code, type,
> + op0,
> + TREE_OPERAND (arg1, 0));
> + /* -X ==/!= CST -> X ==/!= CST' with CST'= -CST. */
> + else if (c2 == INTEGER_CST)
> + return fold_build2_loc (loc, code, type, op0,
> + fold_build1_loc (loc, NEGATE_EXPR,
> + optype, arg1));
> + }
> + else if (c1 == BIT_NOT_EXPR)
> + {
> + op0 = TREE_OPERAND (arg0, 0);
> + /* ~X ==/!= ~Y -> X ==/!= Y. */
> + if (c2 == c1)
> + return fold_build2_loc (loc, code, type, op0,
> + TREE_OPERAND (arg1, 0));
> + /* ~X ==/!= CST -> X ==/!= CST' with CST'= ~CST. */
> + else if (c2 == INTEGER_CST)
> + return fold_build2_loc (loc, code, type, op0,
> + fold_build1_loc (loc, BIT_NOT_EXPR,
> + optype, arg1));
> + }
> +
> + /* See if we can simplify case X == (Y +|-|^ Z). */
> + if (c1 != PLUS_EXPR && c1 != MINUS_EXPR && c1 != BIT_XOR_EXPR)
> + {
> + if ((c2 != PLUS_EXPR && c2 != MINUS_EXPR
> + && c2 != BIT_XOR_EXPR)
> + || TREE_SIDE_EFFECTS (arg0))
> + return NULL_TREE;
> +
> + op0 = TREE_OPERAND (arg1, 0);
> + op1 = TREE_OPERAND (arg1, 1);
> +
> + /* Convert temporary X - Y to X + (-Y). */
> + if (c2 == MINUS_EXPR)
> + op1 = fold_build1_loc (loc, NEGATE_EXPR, optype, op1);
> +
> + /* Check if we can simplify X ==/!= (X ^ Y) to Y ==/!= 0,
> + or X ==/!= (X +|- Y) to Y ==/!= 0. */
> + tem = fold_build2_loc (loc, (c2 == BIT_XOR_EXPR ? c2 : MINUS_EXPR),
> + optype, arg0, op0);
> + if (TREE_CODE (tem) == INTEGER_CST
> + && (integer_zerop (tem) || TYPE_UNSIGNED (optype)
> + || c2 == BIT_XOR_EXPR))
> + return fold_build2_loc (loc, code, type, op1, tem);
> +
> + /* Check if we can simplify X ==/!= (Y ^ X) to Y ==/!= 0,
> + or X ==/!= (Y + X) to Y ==/!= 0. */
> + tem = fold_build2_loc (loc, (c2 == BIT_XOR_EXPR ? c2 : MINUS_EXPR),
> + optype, arg0, op1);
> + if (TREE_CODE (tem) == INTEGER_CST
> + && (integer_zerop (tem) || TYPE_UNSIGNED (optype)
> + || c2 == BIT_XOR_EXPR))
> + return fold_build2_loc (loc, code, type, op0, tem);
> + }
> + else if (c2 != PLUS_EXPR && c2 != MINUS_EXPR && c2 != BIT_XOR_EXPR)
> + {
> + if ((c1 != PLUS_EXPR && c1 != MINUS_EXPR
> + && c1 != BIT_XOR_EXPR)
> + || TREE_SIDE_EFFECTS (arg1))
> + return NULL_TREE;
> +
> + op0 = TREE_OPERAND (arg0, 0);
> + op1 = TREE_OPERAND (arg0, 1);
> +
> + /* Convert temporary X - Y to X + (-Y). */
> + if (c1 == MINUS_EXPR)
> + op1 = fold_build1_loc (loc, NEGATE_EXPR, optype, op1);
> +
> + /* Check if we can simplify X ==/!= (X ^ Y) to Y ==/!= 0,
> + or X ==/!= (X +|- Y) to Y ==/!= 0. */
> + tem = fold_build2_loc (loc, (c1 == BIT_XOR_EXPR ? c1 : MINUS_EXPR),
> + optype, arg1, op0);
> + if (TREE_CODE (tem) == INTEGER_CST
> + && (integer_zerop (tem) || TYPE_UNSIGNED (optype)
> + || c1 == BIT_XOR_EXPR))
> + return fold_build2_loc (loc, code, type, op1, tem);
> +
> + /* Check if we can simplify X ==/!= (Y ^ X) to Y ==/!= 0,
> + or X ==/!= (Y + X) to Y ==/!= 0. */
> + tem = fold_build2_loc (loc, (c1 == BIT_XOR_EXPR ? c1 : MINUS_EXPR),
> + optype, arg1, op1);
> + if (TREE_CODE (tem) == INTEGER_CST
> + && (integer_zerop (tem) || TYPE_UNSIGNED (optype)
> + || c1 == BIT_XOR_EXPR))
> + return fold_build2_loc (loc, code, type, op0, tem);
> + }
> +
> + /* We check if arg1 and arg2 are matching one of the patterns
> + (V + W) ==/!= (X + Y), (V + W) ==/!= (X - Y), (V - W) ==/!= (X + Y),
> + (V - W) ==/!= (X - Y), or (V ^ W) ==/!= (X ^ Y). */
> +
> + if ((c1 != PLUS_EXPR && c1 != MINUS_EXPR && c1 != BIT_XOR_EXPR)
> + || (c2 != PLUS_EXPR && c2 != MINUS_EXPR && c2 != BIT_XOR_EXPR))
> + return NULL_TREE;
> + if (c1 != c2 && (c1 == BIT_XOR_EXPR || c2 == BIT_XOR_EXPR))
> + return NULL_TREE;
> +
> + op0 = TREE_OPERAND (arg0, 0);
> + op1 = TREE_OPERAND (arg0, 1);
> + opr0 = TREE_OPERAND (arg1, 0);
> + opr1 = TREE_OPERAND (arg1, 1);
> +
> + /* Convert temporary (X - Y) to (X + (-Y)). */
> + if (c1 == MINUS_EXPR)
> + {
> + op1 = fold_build1_loc (loc, NEGATE_EXPR, optype, op1);
> + c1 = PLUS_EXPR;
> + }
> +
> + /* Convert temporary (X - Y) to (X + (-Y)). */
> + if (c2 == MINUS_EXPR)
> + {
> + opr1 = fold_build1_loc (loc, NEGATE_EXPR, optype, opr1);
> + c2 = PLUS_EXPR;
> + }
> +
> + if (c1 != c2)
> + return NULL_TREE;
> +
> + /* If OP0 has no side-effects, we might be able to optimize
> + (OP0 + OP1) ==/!= (OP0 + OPR1) to OP1 ==/!= OPR1,
> + (OP0 + OP1) ==/!= (OPR0 + OP0) to OP1 ==/!= OPR0,
> + (OP0 ^ OP1) ==/!= (OP0 ^ OPR1) to OP1 ==/!= OPR1,
> + or (OP0 ^ OP1) ==/!= (OPR0 ^ OP0) to OP1 ==/!= OPR0.. */
> + if (!TREE_SIDE_EFFECTS (op0))
> + {
> + tem = fold_build2_loc (loc, (c1 == PLUS_EXPR ? MINUS_EXPR : c1),
> + optype, op0, opr0);
> + if (TREE_CODE (tem) == INTEGER_CST
> + && !TREE_SIDE_EFFECTS (opr0)
> + && (integer_zerop (tem) || TYPE_UNSIGNED (optype)
> + || c1 == BIT_XOR_EXPR))
> + {
> + if (!integer_zerop (tem))
> + tem = fold_build2_loc (loc, c1, optype, op1, tem);
> + else
> + tem = op1;
> +
> + return fold_build2_loc (loc, code, type, tem, opr1);
> + }
> + tem = fold_build2_loc (loc, (c1 == PLUS_EXPR ? MINUS_EXPR : c1),
> + optype, op0, opr1);
> + if (TREE_CODE (tem) == INTEGER_CST
> + && !TREE_SIDE_EFFECTS (opr1)
> + && (integer_zerop (tem) || TYPE_UNSIGNED (optype)
> + || c1 == BIT_XOR_EXPR))
> + {
> + if (!integer_zerop (tem))
> + tem = fold_build2_loc (loc, c1, optype, op1, tem);
> + else
> + tem = op1;
> + return fold_build2_loc (loc, code, type, tem, opr0);
> + }
> + }
> +
> + /* If OP1 has no side-effects, we might be able to optimize
> + (OP0 + OP1) ==/!= (OP1 + OPR1) to OP0 ==/!= OPR1,
> + (OP0 + OP1) ==/!= (OPR0 + OP1) to OP0 ==/!= OPR0,
> + (OP0 ^ OP1) ==/!= (OP1 ^ OPR1) to OP0 ==/!= OPR1,
> + or (OP0 ^ OP1) ==/!= (OPR0 ^ OP1) to OP0 ==/!= OPR0.. */
> + if (!TREE_SIDE_EFFECTS (op1))
> + {
> + tem = fold_build2_loc (loc, (c1 == PLUS_EXPR ? MINUS_EXPR : c1),
> + optype, op1, opr0);
> + if (TREE_CODE (tem) == INTEGER_CST
> + && !TREE_SIDE_EFFECTS (opr0)
> + && (integer_zerop (tem) || TYPE_UNSIGNED (optype)
> + || c1 == BIT_XOR_EXPR))
> + {
> + if (!integer_zerop (tem))
> + tem = fold_build2_loc (loc, c1, optype, op0, tem);
> + else
> + tem = op0;
> + return fold_build2_loc (loc, code, type, tem, opr1);
> + }
> +
> + tem = fold_build2_loc (loc, (c1 == PLUS_EXPR ? MINUS_EXPR : c1),
> + optype, op1, opr1);
> + if (TREE_CODE (tem) == INTEGER_CST
> + && !TREE_SIDE_EFFECTS (opr1)
> + && (integer_zerop (tem) || TYPE_UNSIGNED (optype)
> + || c1 == BIT_XOR_EXPR))
> + {
> + if (!integer_zerop (tem))
> + tem = fold_build2_loc (loc, c1, optype, op0, tem);
> + else
> + tem = op0;
> + return fold_build2_loc (loc, code, type, tem, opr0);
> + }
> + }
> +
> + return NULL_TREE;
> +}
> +
> /* Subroutine of fold_binary. This routine performs all of the
> transformations that are common to the equality/inequality
> operators (EQ_EXPR and NE_EXPR) and the ordering operators
> @@ -8767,6 +9002,10 @@ fold_comparison (location_t loc, enum tr
> if (tree_swap_operands_p (arg0, arg1, true))
> return fold_build2_loc (loc, swap_tree_comparison (code), type, op1, op0);
>
> + tem = fold_comparison_1 (loc, code, type, arg0, arg1);
> + if (tem != NULL_TREE)
> + return tem;
> +
> /* 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)
> && (TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
> Index: gcc/gcc/testsuite/gcc.dg/fold-compare-1.c
> ===================================================================
> --- gcc.orig/gcc/testsuite/gcc.dg/fold-compare-1.c
> +++ gcc/gcc/testsuite/gcc.dg/fold-compare-1.c
> @@ -41,7 +41,7 @@ int test8(int l)
> return ~l >= 2;
> }
>
> -/* { dg-final { scan-tree-dump-times "b == a" 1 "original" } } */
> +/* { dg-final { scan-tree-dump-times "b == a|a == b" 1 "original" } } */
> /* { dg-final { scan-tree-dump-times "c == d" 1 "original" } } */
> /* { dg-final { scan-tree-dump-times "e == -5" 1 "original" } } */
> /* { dg-final { scan-tree-dump-times "f == -6" 1 "original" } } */
> Index: gcc/gcc/testsuite/gcc.dg/fold-compare-7.c
> ===================================================================
> --- /dev/null
> +++ gcc/gcc/testsuite/gcc.dg/fold-compare-7.c
> @@ -0,0 +1,36 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-original" } */
> +
> +int test1(int a, int elim)
> +{
> + return ~elim == (elim ^ a);
> +}
> +
> +int test2(int elim, int b)
> +{
> + return -elim == (b - elim);
> +}
> +
> +int test3(int c, int elim, int d)
> +{
> + return (c + elim) != (elim + d);
> +}
> +
> +int test4(int e, int f, int elim)
> +{
> + return (e - elim) != (-elim + f);
> +}
> +
> +int test5(int g, int h, int elim)
> +{
> + return (elim ^ g) == (h ^ elim);
> +}
> +
> +int test6(int i, int j, int elim)
> +{
> + return (elim ^ i) == (j ^ ~elim);
> +}
> +
> +/* { dg-final { scan-tree-dump-times "elim" 0 "original" } } */
> +/* { dg-final { cleanup-tree-dump "original" } } */
> +
--
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