The existing transform
(and X (ior (not X) Y) -> (and X Y)
has two shortcomings: it only handles identical RTX for X, i.e. registers,
not e.g. subregs of registers; and it only handles the case where the NOT
is the first arm of the IOR (it can be the second arm e.g. if the first
arm is a NOT as well). Fix both. This fixes gcc.dg/and-1.c on powerpc64.
Bootstrapped and tested on powerpc64-linux; okay for mainline?
Segher
2014-12-24 Segher Boessenkool <seg...@kernel.crashing.org>
gcc/
* simplify-rtx.c (simplify_binary_operation_1): Handle more cases
for the "(and X (ior (not X) Y) -> (and X Y)" transform.
---
gcc/simplify-rtx.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index 277288a..ae0b49d 100644
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -2933,15 +2933,27 @@ simplify_binary_operation_1 (enum rtx_code code,
machine_mode mode,
/* (and X (ior (not X) Y) -> (and X Y) */
if (GET_CODE (op1) == IOR
&& GET_CODE (XEXP (op1, 0)) == NOT
- && op0 == XEXP (XEXP (op1, 0), 0))
+ && rtx_equal_p (op0, XEXP (XEXP (op1, 0), 0)))
return simplify_gen_binary (AND, mode, op0, XEXP (op1, 1));
/* (and (ior (not X) Y) X) -> (and X Y) */
if (GET_CODE (op0) == IOR
&& GET_CODE (XEXP (op0, 0)) == NOT
- && op1 == XEXP (XEXP (op0, 0), 0))
+ && rtx_equal_p (op1, XEXP (XEXP (op0, 0), 0)))
return simplify_gen_binary (AND, mode, op1, XEXP (op0, 1));
+ /* (and X (ior Y (not X)) -> (and X Y) */
+ if (GET_CODE (op1) == IOR
+ && GET_CODE (XEXP (op1, 1)) == NOT
+ && rtx_equal_p (op0, XEXP (XEXP (op1, 1), 0)))
+ return simplify_gen_binary (AND, mode, op0, XEXP (op1, 0));
+
+ /* (and (ior Y (not X)) X) -> (and X Y) */
+ if (GET_CODE (op0) == IOR
+ && GET_CODE (XEXP (op0, 1)) == NOT
+ && rtx_equal_p (op1, XEXP (XEXP (op0, 1), 0)))
+ return simplify_gen_binary (AND, mode, op1, XEXP (op0, 0));
+
tem = simplify_byte_swapping_operation (code, mode, op0, op1);
if (tem)
return tem;
--
1.8.1.4
