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MATCH: Move (x | y) & (~x ^ y) over to use bitwise_inverted_equal_p

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This moves the match pattern `(x | y) & (~x ^ y)` over to use bitwise_inverted_equal_p.
This now also allows to optmize comparisons and also catches the missed `(~x | y) & (x ^ y)`
transformation into `~x & y`.

OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

gcc/ChangeLog:

	PR tree-optimization/111147
	* match.pd (`(x | y) & (~x ^ y)`) Use bitwise_inverted_equal_p
	instead of matching bit_not.

gcc/testsuite/ChangeLog:

	PR tree-optimization/111147
	* gcc.dg/tree-ssa/cmpbit-4.c: New test.
This commit is contained in:
Andrew Pinski 2023-08-28 10:04:00 -07:00
parent 97aafa9cbb
commit 7c04da768c
2 changed files with 52 additions and 2 deletions
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7
gcc/match.pd
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@ -1616,8 +1616,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
/* (x | y) & (~x ^ y) -> x & y */
(simplify
(bit_and:c (bit_ior:c @0 @1) (bit_xor:c @1 (bit_not @0)))
(bit_and @0 @1))
(bit_and:c (bit_ior:c @0 @1) (bit_xor:c @1 @2))
(with { bool wascmp; }
(if (bitwise_inverted_equal_p (@0, @2, wascmp)
&& (!wascmp || element_precision (type) == 1))
(bit_and @0 @1))))
/* (~x | y) & (x | ~y) -> ~(x ^ y) */
(simplify

47
gcc/testsuite/gcc.dg/tree-ssa/cmpbit-4.c Normal file
View file

@ -0,0 +1,47 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-optimized-raw" } */
int g(int x, int y)
{
int xp = ~x;
return (x | y) & (xp ^ y); // x & y
}
int g0(int x, int y)
{
int xp = ~x;
return (xp | y) & (x ^ y); // ~x & y
}
_Bool gb(_Bool x, _Bool y)
{
_Bool xp = !x;
return (x | y) & (xp ^ y); // x & y
}
_Bool gb0(_Bool x, _Bool y)
{
_Bool xp = !x;
return (xp | y) & (x ^ y); // !x & y
}
_Bool gbi(int a, int b)
{
_Bool x = a < 2;
_Bool y = b < 3;
_Bool xp = !x;
return (x | y) & (xp ^ y); // x & y
}
_Bool gbi0(int a, int b)
{
_Bool x = a < 2;
_Bool y = b < 3;
_Bool xp = !x;
return (xp | y) & (x ^ y); // !x & y
}
/* All of these should be optimized to `x & y` or `~x & y` */
/* { dg-final { scan-tree-dump-times "le_expr, " 3 "optimized" } } */
/* { dg-final { scan-tree-dump-times "gt_expr, " 1 "optimized" } } */
/* { dg-final { scan-tree-dump-not "bit_xor_expr, " "optimized" } } */
/* { dg-final { scan-tree-dump-times "bit_and_expr, " 6 "optimized" } } */
/* { dg-final { scan-tree-dump-times "bit_not_expr, " 2 "optimized" } } */