FreeChainXenon/gcc
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

x & C -> x if we know that x & ~C == 0

Browse source 
2016-05-17  Marc Glisse  <marc.glisse@inria.fr>

gcc/
	* match.pd (X & C): New transformation.

gcc/testsuite/
	* gcc.dg/tree-ssa/and-1.c: New testcase.

From-SVN: r236338
This commit is contained in:
Marc Glisse 2016-05-17 19:57:27 +02:00 • committed by Marc Glisse
parent d982c5b7b7
commit c7986356a1
4 changed files with 28 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
gcc/ChangeLog
View file

@ -1,3 +1,7 @@
2016-05-17 Marc Glisse <marc.glisse@inria.fr>
* match.pd (X & C): New transformation.
2016-05-17 Marc Glisse <marc.glisse@inria.fr>
* match.pd (~X & Y): New transformation.

9
gcc/match.pd
View file

@ -563,6 +563,15 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(bitop @0 @0)
(non_lvalue @0)))
/* x & C -> x if we know that x & ~C == 0. */
#if GIMPLE
(simplify
(bit_and SSA_NAME@0 INTEGER_CST@1)
(if (INTEGRAL_TYPE_P (TREE_TYPE (@0))
&& (get_nonzero_bits (@0) & wi::bit_not (@1)) == 0)
@0))
#endif
/* x + (x & 1) -> (x + 1) & ~1 */
(simplify
(plus:c @0 (bit_and:s @0 integer_onep@1))

4
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,7 @@
2016-05-17 Marc Glisse <marc.glisse@inria.fr>
* gcc.dg/tree-ssa/and-1.c: New testcase.
2016-05-17 Marc Glisse <marc.glisse@inria.fr>
* gcc.dg/tree-ssa/pr69270.c: Adjust.

11
gcc/testsuite/gcc.dg/tree-ssa/and-1.c Normal file
View file

@ -0,0 +1,11 @@
/* { dg-do compile } */
/* { dg-options "-O -fdump-tree-optimized-raw" } */
int f(int in) {
in = in | 3;
in = in ^ 1;
in = (in & ~(unsigned long)1);
return in;
}
/* { dg-final { scan-tree-dump-not "bit_and_expr" "optimized" } } */