From 2d9474dfd2b300d6a10b541ef5a282759a1ca190 Mon Sep 17 00:00:00 2001 From: "James A. Morrison" Date: Sat, 18 Jun 2005 19:57:12 +0000 Subject: [PATCH] fold_const (fold_binary): Fold X % (2**N) to X & (2**N - 1) for nonnegative values of X. 2005-06-18 James A. Morrison * fold_const (fold_binary): Fold X % (2**N) to X & (2**N - 1) for nonnegative values of X. From-SVN: r101163 --- gcc/ChangeLog | 5 +++++ gcc/fold-const.c | 10 +++++----- gcc/testsuite/ChangeLog | 4 ++++ gcc/testsuite/gcc.dg/fold-mod-1.c | 25 +++++++++++++++++++++++++ 4 files changed, 39 insertions(+), 5 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/fold-mod-1.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 2fefbb6f94e..52c3a968689 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2005-06-18 James A. Morrison + + * fold_const (fold_binary): Fold X % (2**N) to X & (2**N - 1) for + nonnegative values of X. + 2005-06-18 Uros Bizjak * doc/md.texi (Standard Names): Change insn pattern name diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 8433d1dfd98..335e556f5e9 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -8337,11 +8337,11 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1) && TREE_INT_CST_HIGH (arg1) == -1) return omit_one_operand (type, integer_zero_node, arg0); - /* Optimize unsigned TRUNC_MOD_EXPR by a power of two into a - BIT_AND_EXPR, i.e. "X % C" into "X & C2". */ - if (code == TRUNC_MOD_EXPR - && TYPE_UNSIGNED (type) - && integer_pow2p (arg1)) + /* Optimize TRUNC_MOD_EXPR by a power of two into a BIT_AND_EXPR, + i.e. "X % C" into "X & C2", if X and C are positive. */ + if ((code == TRUNC_MOD_EXPR || code == FLOOR_MOD_EXPR) + && (TYPE_UNSIGNED (type) || tree_expr_nonnegative_p (arg0)) + && integer_pow2p (arg1) && tree_int_cst_sgn (arg1) >= 0) { unsigned HOST_WIDE_INT high, low; tree mask; diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 2b7719cf1c6..31c4c10b262 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2005-06-18 James A Morrison + + * gcc.dg/fold-mod-1.c: New test. + 2005-06-18 Steven G. Kargl PR fortran/19926 diff --git a/gcc/testsuite/gcc.dg/fold-mod-1.c b/gcc/testsuite/gcc.dg/fold-mod-1.c new file mode 100644 index 00000000000..1b312ea8c27 --- /dev/null +++ b/gcc/testsuite/gcc.dg/fold-mod-1.c @@ -0,0 +1,25 @@ +/* { dg-do compile } */ +/* { dg-options "-fdump-tree-gimple" } */ + +#define ABS(x) (x > 0 ? x : -x) + +unsigned int f (unsigned int a) { + /* (unsigned)-8 is not a power of 2. */ + return a % -8; +} + +int g (int b) { + return ABS (b) % -8; +} + +int h (int c) { + return ABS (c) % 8; +} + +unsigned int k (unsigned int d) { + return d % 8; +} + +/* { dg-final { scan-tree-dump "a % 4294967288" "gimple" } } */ +/* { dg-final { scan-tree-dump-times " & 7" 3 "gimple" } } */ +/* { dg-final { cleanup-tree-dump "gimple" } } */ -- 2.30.2