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re PR tree-optimization/20130 (Fold a * -1 - 1 into ~a;)

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2005-03-11  James A. Morrison  <phython@gcc.gnu.org>

       PR tree-optimization/20130
       * fold-const.c (fold): Fold x * -1 into -x.

From-SVN: r96283
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James A. Morrison 2005-03-11 03:18:56 +00:00
parent 550b7784c6
commit 694d73e165
4 changed files with 27 additions and 0 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2005-03-11 James A. Morrison <phython@gcc.gnu.org>
PR tree-optimization/20130
* fold-const.c (fold): Fold x * -1 into -x.
2005-03-11 Kaz Kojima <kkojima@gcc.gnu.org>
PR rtl-optimization/20331

3
gcc/fold-const.c
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@ -7785,6 +7785,9 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
return omit_one_operand (type, arg1, arg0);
if (integer_onep (arg1))
return non_lvalue (fold_convert (type, arg0));
/* Transform x * -1 into -x. */
if (integer_all_onesp (arg1))
return fold_convert (type, negate_expr (arg0));
/* (a * (1 << b)) is (a << b) */
if (TREE_CODE (arg1) == LSHIFT_EXPR

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2005-03-10 James A. Morrison <phython@gcc.gnu.org>
PR tree-optimization/20130
* gcc.dg/pr20130-1.c: New test.
2005-03-10 Steve Ellcey <sje@cup.hp.com>
PR target/20095

14
gcc/testsuite/gcc.dg/pr20130-1.c Normal file
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@ -0,0 +1,14 @@
/* { dg-do compile } */
/* { dg-options "-fdump-tree-generic" } */
int z (int a) {
return a * -1;
}
int x (int a) {
return -1 * a;
}
int y (int a) {
return -(-1 * -a);
}
/* { dg-final { scan-tree-dump-times "-a" 3 "generic" } } */