From 7ddc480e76afa04fbbe106a5df8fe571f04087a2 Mon Sep 17 00:00:00 2001 From: sayle Date: Sun, 26 Feb 2006 16:10:30 +0000 Subject: [PATCH] * fold-const.c (fold_binary) : Fold (X & 1) ^ 1 as (X & 1) == 0. : Fold (X ^ 1) & 1 and ~X & 1 as (X & 1) == 0. * gcc.dg/fold-even-1.c: New test case. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@111454 138bc75d-0d04-0410-961f-82ee72b054a4 --- gcc/ChangeLog | 6 ++++++ gcc/fold-const.c | 29 +++++++++++++++++++++++++++++ gcc/testsuite/ChangeLog | 4 ++++ gcc/testsuite/gcc.dg/fold-even-1.c | 33 +++++++++++++++++++++++++++++++++ 4 files changed, 72 insertions(+) create mode 100644 gcc/testsuite/gcc.dg/fold-even-1.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index ead872d398c..90cff90c880 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,4 +1,10 @@ 2006-02-26 Roger Sayle + + * fold-const.c (fold_binary) : Fold (X & 1) ^ 1 as + (X & 1) == 0. + : Fold (X ^ 1) & 1 and ~X & 1 as (X & 1) == 0. + +2006-02-26 Roger Sayle James A. Morrison PR middle-end/21137 diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 7eb4d914e92..e85534ab2e1 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -8740,6 +8740,13 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1) fold_convert (type, TREE_OPERAND (arg0, 0)), fold_convert (type, TREE_OPERAND (arg1, 0))); + /* Fold (X & 1) ^ 1 as (X & 1) == 0. */ + if (TREE_CODE (arg0) == BIT_AND_EXPR + && integer_onep (TREE_OPERAND (arg0, 1)) + && integer_onep (arg1)) + return fold_build2 (EQ_EXPR, type, arg0, + build_int_cst (TREE_TYPE (arg0), 0)); + /* See if this can be simplified into a rotate first. If that is unsuccessful continue in the association code. */ goto bit_rotate; @@ -8792,6 +8799,28 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1) && reorder_operands_p (arg0, TREE_OPERAND (arg1, 0))) return omit_one_operand (type, arg0, TREE_OPERAND (arg1, 0)); + /* Fold (X ^ 1) & 1 as (X & 1) == 0. */ + if (TREE_CODE (arg0) == BIT_XOR_EXPR + && integer_onep (TREE_OPERAND (arg0, 1)) + && integer_onep (arg1)) + { + tem = TREE_OPERAND (arg0, 0); + return fold_build2 (EQ_EXPR, type, + fold_build2 (BIT_AND_EXPR, TREE_TYPE (tem), tem, + build_int_cst (TREE_TYPE (tem), 1)), + build_int_cst (TREE_TYPE (tem), 0)); + } + /* Fold ~X & 1 as (X & 1) == 0. */ + if (TREE_CODE (arg0) == BIT_NOT_EXPR + && integer_onep (arg1)) + { + tem = TREE_OPERAND (arg0, 0); + return fold_build2 (EQ_EXPR, type, + fold_build2 (BIT_AND_EXPR, TREE_TYPE (tem), tem, + build_int_cst (TREE_TYPE (tem), 1)), + build_int_cst (TREE_TYPE (tem), 0)); + } + t1 = distribute_bit_expr (code, type, arg0, arg1); if (t1 != NULL_TREE) return t1; diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index deb3000d167..a93b73c6637 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,5 +1,9 @@ 2006-02-26 Roger Sayle + * gcc.dg/fold-even-1.c: New test case. + +2006-02-26 Roger Sayle + PR middle-end/21137 * gcc.dg/fold-eqandshift-1.c: New test case. diff --git a/gcc/testsuite/gcc.dg/fold-even-1.c b/gcc/testsuite/gcc.dg/fold-even-1.c new file mode 100644 index 00000000000..8e6539c924d --- /dev/null +++ b/gcc/testsuite/gcc.dg/fold-even-1.c @@ -0,0 +1,33 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-original" } */ +int test1(int a) +{ + return !(a & 1); +} + +int test2(int b) +{ + return (b & 1) == 0; +} + +int test3(int c) +{ + return (c & 1) ^ 1; +} + +int test4(int d) +{ + return (d ^ 1) & 1; +} + +int test5(int e) +{ + return ~e & 1; +} + +/* { dg-final { scan-tree-dump-times "\\(a \& 1\\) == 0" 1 "original" } } */ +/* { dg-final { scan-tree-dump-times "\\(b \& 1\\) == 0" 1 "original" } } */ +/* { dg-final { scan-tree-dump-times "\\(c \& 1\\) == 0" 1 "original" } } */ +/* { dg-final { scan-tree-dump-times "\\(d \& 1\\) == 0" 1 "original" } } */ +/* { dg-final { scan-tree-dump-times "\\(e \& 1\\) == 0" 1 "original" } } */ +/* { dg-final { cleanup-tree-dump "original" } } */ -- 2.11.0