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re PR middle-end/71762 (~X & Y to X < Y doesn't work for uninitialized values)

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2016-11-23  Richard Biener  <rguenther@suse.de>

	PR middle-end/71762
	* match.pd ((~X & Y) -> X < Y, (X & ~Y) -> Y < X,
	(~X | Y) -> X <= Y, (X | ~Y) -> Y <= X): Remove.

	* gcc.dg/torture/pr71762-1.c: New testcase.
	* gcc.dg/torture/pr71762-2.c: Likewise.
	* gcc.dg/torture/pr71762-3.c: Likewise.
	* gcc.dg/tree-ssa/forwprop-28.c: XFAIL.

From-SVN: r242747
This commit is contained in:
Richard Biener 2016-11-23 11:33:03 +00:00 committed by Richard Biener
parent efb7123241
commit 0eb078fe20
6 changed files with 71 additions and 27 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2016-11-23 Richard Biener <rguenther@suse.de>
PR middle-end/71762
* match.pd ((~X & Y) -> X < Y, (X & ~Y) -> Y < X,
(~X | Y) -> X <= Y, (X | ~Y) -> Y <= X): Remove.
2016-11-23 Richard Biener <rguenther@suse.de>
PR lto/78472

27
gcc/match.pd
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@ -963,33 +963,6 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(op:c truth_valued_p@0 (logical_inverted_value @0))
{ constant_boolean_node (op == NE_EXPR ? true : false, type); }))
/* If arg1 and arg2 are booleans (or any single bit type)
then try to simplify:
(~X & Y) -> X < Y
(X & ~Y) -> Y < X
(~X | Y) -> X <= Y
(X | ~Y) -> Y <= X
But only do this if our result feeds into a comparison as
this transformation is not always a win, particularly on
targets with and-not instructions.
-> simplify_bitwise_binary_boolean */
(simplify
(ne (bit_and:c (bit_not @0) @1) integer_zerop)
(if (INTEGRAL_TYPE_P (TREE_TYPE (@1))
&& TYPE_PRECISION (TREE_TYPE (@1)) == 1)
(if (TYPE_UNSIGNED (TREE_TYPE (@1)))
(lt @0 @1)
(gt @0 @1))))
(simplify
(ne (bit_ior:c (bit_not @0) @1) integer_zerop)
(if (INTEGRAL_TYPE_P (TREE_TYPE (@1))
&& TYPE_PRECISION (TREE_TYPE (@1)) == 1)
(if (TYPE_UNSIGNED (TREE_TYPE (@1)))
(le @0 @1)
(ge @0 @1))))
/* ~~x -> x */
(simplify
(bit_not (bit_not @0))

8
gcc/testsuite/ChangeLog
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@ -1,3 +1,11 @@
2016-11-23 Richard Biener <rguenther@suse.de>
PR middle-end/71762
* gcc.dg/torture/pr71762-1.c: New testcase.
* gcc.dg/torture/pr71762-2.c: Likewise.
* gcc.dg/torture/pr71762-3.c: Likewise.
* gcc.dg/tree-ssa/forwprop-28.c: XFAIL.
2016-11-23 Richard Biener <rguenther@suse.de>
PR lto/78472

18
gcc/testsuite/gcc.dg/torture/pr71762-1.c Normal file
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@ -0,0 +1,18 @@
/* { dg-do run } */
/* { dg-additional-options "-fdisable-rtl-init-regs" } */
static _Bool
foo (_Bool a, _Bool b)
{
int x = a && ! b;
return x != 0;
}
int y = 1;
int main()
{
_Bool x;
if (foo (x, y))
__builtin_abort ();
return 0;
}

17
gcc/testsuite/gcc.dg/torture/pr71762-2.c Normal file
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@ -0,0 +1,17 @@
/* { dg-do run } */
static _Bool
foo (_Bool a, _Bool b)
{
int x = a && ! b;
return x != 0;
}
int y = 1;
int main()
{
_Bool x[32];
if (foo (x[1], y))
__builtin_abort ();
return 0;
}

22
gcc/testsuite/gcc.dg/torture/pr71762-3.c Normal file
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@ -0,0 +1,22 @@
/* { dg-do run } */
static _Bool
foo (_Bool a, _Bool b)
{
int x = a && ! b;
return x != 0;
}
int y = 1;
int main()
{
register _Bool x
/* Add register spec for the argv parameter to main. */
#if __i386__ || __x86_64__
__asm__("%esi")
#endif
;
if (foo (x, y))
__builtin_abort ();
return 0;
}