re PR middle-end/30322 (((-i-1) + i) +1) is turned into ~i + (i+1) and never into 0 on the tree level)
PR middle-end/30322 * fold-const.c (fold_binary): Fold X + ~X and ~X + X into -1 when we don't care about trapping overflow. Only convert -A - 1 into ~A when we don't care about trapping overflow. * gcc.dg/fold-plusnot-1.c: New test case. From-SVN: r120300
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2006-12-31 Roger Sayle <roger@eyesopen.com>
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PR middle-end/30322
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* fold-const.c (fold_binary): Fold X + ~X and ~X + X into -1 when
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we don't care about trapping overflow. Only convert -A - 1 into ~A
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when we don't care about trapping overflow.
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2006-12-31 Richard Guenther <rguenther@suse.de>
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2006-12-31 Richard Guenther <rguenther@suse.de>
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PR middle-end/30338
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PR middle-end/30338
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@ -8662,6 +8662,26 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
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if (integer_zerop (arg1))
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if (integer_zerop (arg1))
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return non_lvalue (fold_convert (type, arg0));
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return non_lvalue (fold_convert (type, arg0));
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/* ~X + X is -1. */
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if (TREE_CODE (arg0) == BIT_NOT_EXPR
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&& operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)
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&& !TYPE_TRAP_SIGNED (type))
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{
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t1 = build_int_cst (type, -1);
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t1 = force_fit_type (t1, 0, false, false);
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return omit_one_operand (type, t1, arg1);
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}
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/* X + ~X is -1. */
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if (TREE_CODE (arg1) == BIT_NOT_EXPR
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&& operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)
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&& !TYPE_TRAP_SIGNED (type))
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{
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t1 = build_int_cst (type, -1);
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t1 = force_fit_type (t1, 0, false, false);
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return omit_one_operand (type, t1, arg0);
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}
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/* If we are adding two BIT_AND_EXPR's, both of which are and'ing
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/* If we are adding two BIT_AND_EXPR's, both of which are and'ing
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with a constant, and the two constants have no bits in common,
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with a constant, and the two constants have no bits in common,
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we should treat this as a BIT_IOR_EXPR since this may produce more
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we should treat this as a BIT_IOR_EXPR since this may produce more
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@ -9002,7 +9022,8 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
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/* Convert -A - 1 to ~A. */
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/* Convert -A - 1 to ~A. */
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if (INTEGRAL_TYPE_P (type)
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if (INTEGRAL_TYPE_P (type)
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&& TREE_CODE (arg0) == NEGATE_EXPR
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&& TREE_CODE (arg0) == NEGATE_EXPR
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&& integer_onep (arg1))
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&& integer_onep (arg1)
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&& !TYPE_TRAP_SIGNED (type))
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return fold_build1 (BIT_NOT_EXPR, type,
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return fold_build1 (BIT_NOT_EXPR, type,
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fold_convert (type, TREE_OPERAND (arg0, 0)));
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fold_convert (type, TREE_OPERAND (arg0, 0)));
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@ -1,3 +1,8 @@
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2006-12-31 Roger Sayle <roger@eyesopen.com>
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PR middle-end/30322
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* gcc.dg/fold-plusnot-1.c: New test case.
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2006-12-31 Simon Martin <simartin@users.sourceforge.net>
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2006-12-31 Simon Martin <simartin@users.sourceforge.net>
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PR c++/29731
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PR c++/29731
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@ -0,0 +1,30 @@
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/* PR middle-end/30322 */
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/* { dg-do compile } */
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/* { dg-options "-O2 -fdump-tree-original" } */
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int test1(int a)
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{
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return a + ~a;
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}
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int test2(int b)
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{
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return ~b + b;
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}
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unsigned int test3(unsigned int c)
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{
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return c + ~c;
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}
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unsigned int test4(unsigned int d)
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{
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return ~d + d;
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}
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/* { dg-final { scan-tree-dump-times "\\+ a" 0 "original" } } */
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/* { dg-final { scan-tree-dump-times "\\+ b" 0 "original" } } */
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/* { dg-final { scan-tree-dump-times "\\+ c" 0 "original" } } */
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/* { dg-final { scan-tree-dump-times "\\+ d" 0 "original" } } */
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/* { dg-final { cleanup-tree-dump "original" } } */
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