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| author | James A. Morrison <phython@gcc.gnu.org> | 2005-06-18 19:57:12 +0000 |
|---|---|---|
| committer | James A. Morrison <phython@gcc.gnu.org> | 2005-06-18 19:57:12 +0000 |
| commit | 2d9474dfd2b300d6a10b541ef5a282759a1ca190 (patch) | |
| tree | 9030eac2ba4b6f77300c26c535cf1365cacfaf7f /gcc | |
| parent | 5190a458bbace7bd99887361bc7e9f05112908dd (diff) | |
| download | gcc-2d9474dfd2b300d6a10b541ef5a282759a1ca190.zip gcc-2d9474dfd2b300d6a10b541ef5a282759a1ca190.tar.gz gcc-2d9474dfd2b300d6a10b541ef5a282759a1ca190.tar.bz2 | |
fold_const (fold_binary): Fold X % (2**N) to X & (2**N - 1) for nonnegative values of X.
2005-06-18 James A. Morrison <phython@gcc.gnu.org>
* fold_const (fold_binary): Fold X % (2**N) to X & (2**N - 1) for
nonnegative values of X.
From-SVN: r101163
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/fold-const.c | 10 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/fold-mod-1.c | 25 |
4 files changed, 39 insertions, 5 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 2fefbb6..52c3a96 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2005-06-18 James A. Morrison <phython@gcc.gnu.org> + + * fold_const (fold_binary): Fold X % (2**N) to X & (2**N - 1) for + nonnegative values of X. + 2005-06-18 Uros Bizjak <uros@kss-loka.si> * doc/md.texi (Standard Names): Change insn pattern name diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 8433d1d..335e556 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 2b7719c..31c4c10 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2005-06-18 James A Morrison <phython@gcc.gnu.org> + + * gcc.dg/fold-mod-1.c: New test. + 2005-06-18 Steven G. Kargl <kargls@comcast.net> 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 0000000..1b312ea --- /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" } } */ |