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re PR tree-optimization/71636 (Missed optimization in variable alignment test) 

2016-10-17  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>

	PR tree-optimization/71636
	* match.pd (x & ((1 << b) - 1) -> x & ~(~0 << b)): New pattern.

testsuite/
	* gcc.dg/pr71636-1.c: New test-case.
	* gcc.dg/pr71636-2.c: Likewise.

From-SVN: r241229
This commit is contained in:
Prathamesh Kulkarni 2016-10-17 08:48:43 +00:00 committed by Prathamesh Kulkarni
parent d6b1fea25c
commit 89b80c429a
5 changed files with 37 additions and 0 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2016-10-17 Prathamesh Kulkarni <prathamesh.kulkarni@linaro.org>
PR tree-optimization/71636
* match.pd (x & ((1 << b) - 1) -> x & ~(~0 << b)): New pattern.
2016-10-17 Richard Biener <rguenther@suse.de>
* gimplify.c (gimplify_function_tree): Do not move the outer

6
gcc/match.pd
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@ -513,6 +513,12 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(bit_and:c (convert? @0) (convert? (bit_not @0)))
{ build_zero_cst (type); })
/* PR71636: Transform x & ((1U << b) - 1) -> x & ~(~0U << b); */
(simplify
(bit_and:c @0 (plus:s (lshift:s integer_onep @1) integer_minus_onep))
(if (TYPE_UNSIGNED (type))
(bit_and @0 (bit_not (lshift { build_all_ones_cst (type); } @1)))))
/* Fold (A & ~B) - (A & B) into (A ^ B) - B. */
(simplify
(minus (bit_and:cs @0 (bit_not @1)) (bit_and:cs @0 @1))

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2016-10-17 Prathamesh Kulkarni <prathamesh.kulkarni@linaro.org>
* gcc.dg/pr71636-1.c: New test-case.
* gcc.dg/pr71636-2.c: Likewise.
2016-10-16 Eric Botcazou <ebotcazou@adacore.com>
* gnat.dg/trampoline3.adb: New test.

9
gcc/testsuite/gcc.dg/pr71636-1.c Normal file
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@ -0,0 +1,9 @@
/* { dg-do compile } */
/* { dg-options "-fdump-tree-gimple" } */
unsigned f(unsigned x, unsigned b)
{
return x & ((1U << b) - 1);
}
/* { dg-final { scan-tree-dump-not "1 <<" "gimple" } } */

12
gcc/testsuite/gcc.dg/pr71636-2.c Normal file
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@ -0,0 +1,12 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-forwprop-details" } */
unsigned f(unsigned x, unsigned b)
{
unsigned t1 = 1U << b;
unsigned t2 = t1 - 1;
unsigned t3 = x & t2;
return t3;
}
/* { dg-final { scan-tree-dump "_\[0-9\] = ~_\[0-9\]" "forwprop1" } } */