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re PR tree-optimization/34027 (-Os code size nearly doubled)

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2007-11-12  Richard Guenther  <rguenther@suse.de>

	PR middle-end/34027
	* fold-const.c (fold_binary): Fold n - (n / m) * m to n % m.
	(fold_binary): Fold unsinged FLOOR_DIV_EXPR to TRUNC_DIV_EXPR.

	* gcc.dg/pr34027-1.c: New testcase.
	* gcc.dg/pr34027-2.c: Likewise.

From-SVN: r130097
This commit is contained in:
Richard Guenther 2007-11-12 13:24:06 +00:00 • committed by Richard Biener
parent 50d76c246f
commit 65648dd47e
5 changed files with 73 additions and 0 deletions
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9
gcc/ChangeLog
View file

@ -1,3 +1,12 @@
2007-11-12 Richard Guenther <rguenther@suse.de>
PR middle-end/34027
* fold-const.c (fold_binary): Fold n - (n / m) * m to n % m.
(fold_binary): Fold unsinged FLOOR_DIV_EXPR to TRUNC_DIV_EXPR.
* gcc.dg/pr34027-1.c: New testcase.
* gcc.dg/pr34027-2.c: Likewise.
2007-11-12 Ira Rosen <irar@il.ibm.com>
PR tree-optimization/33953

36
gcc/fold-const.c
View file

@ -9653,6 +9653,21 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
return omit_one_operand (type, t1, arg0);
}
}
/* X + (X / CST) * -CST is X % CST. */
if (TREE_CODE (arg1) == MULT_EXPR
&& TREE_CODE (TREE_OPERAND (arg1, 0)) == TRUNC_DIV_EXPR
&& operand_equal_p (arg0,
TREE_OPERAND (TREE_OPERAND (arg1, 0), 0), 0))
{
tree cst0 = TREE_OPERAND (TREE_OPERAND (arg1, 0), 1);
tree cst1 = TREE_OPERAND (arg1, 1);
tree sum = fold_binary (PLUS_EXPR, TREE_TYPE (cst1), cst1, cst0);
if (sum && integer_zerop (sum))
return fold_convert (type,
fold_build2 (TRUNC_MOD_EXPR,
TREE_TYPE (arg0), arg0, cst0));
}
}
/* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the
@ -10061,6 +10076,19 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
&& integer_all_onesp (arg0))
return fold_build1 (BIT_NOT_EXPR, type, op1);
/* X - (X / CST) * CST is X % CST. */
if (INTEGRAL_TYPE_P (type)
&& TREE_CODE (arg1) == MULT_EXPR
&& TREE_CODE (TREE_OPERAND (arg1, 0)) == TRUNC_DIV_EXPR
&& operand_equal_p (arg0,
TREE_OPERAND (TREE_OPERAND (arg1, 0), 0), 0)
&& operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg1, 0), 1),
TREE_OPERAND (arg1, 1), 0))
return fold_convert (type,
fold_build2 (TRUNC_MOD_EXPR, TREE_TYPE (arg0),
arg0, TREE_OPERAND (arg1, 1)));
if (! FLOAT_TYPE_P (type))
{
if (integer_zerop (arg0))
@ -11221,6 +11249,14 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
fold_convert (type, arg0), sh_cnt);
}
}
/* For unsigned integral types, FLOOR_DIV_EXPR is the same as
TRUNC_DIV_EXPR. Rewrite into the latter in this case. */
if (INTEGRAL_TYPE_P (type)
&& TYPE_UNSIGNED (type)
&& code == FLOOR_DIV_EXPR)
return fold_build2 (TRUNC_DIV_EXPR, type, op0, op1);
/* Fall thru */
case ROUND_DIV_EXPR:

6
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,9 @@
2007-11-12 Richard Guenther <rguenther@suse.de>
PR middle-end/34027
* gcc.dg/pr34027-1.c: New testcase.
* gcc.dg/pr34027-2.c: Likewise.
2007-11-12 Ira Rosen <irar@il.ibm.com>
PR tree-optimization/33953

12
gcc/testsuite/gcc.dg/pr34027-1.c Normal file
View file

@ -0,0 +1,12 @@
/* { dg-do compile } */
/* { dg-options "-Os -fdump-tree-optimized" } */
unsigned long foobar(unsigned long ns)
{
while(ns >= 10000L)
ns -= 10000L;
return ns;
}
/* { dg-final { scan-tree-dump "ns % 10000" "optimized" } } */
/* { dg-final { cleanup-tree-dump "optimized" } } */

10
gcc/testsuite/gcc.dg/pr34027-2.c Normal file
View file

@ -0,0 +1,10 @@
/* { dg-do compile } */
/* { dg-options "-fdump-tree-gimple" } */
long foo(long n, long m)
{
return n - (n / m) * m;
}
/* { dg-final { scan-tree-dump "n % m" "gimple" } } */
/* { dg-final { cleanup-tree-dump "gimple" } } */