diff options
| -rw-r--r-- | gcc/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/simplify-rtx.c | 31 |
2 files changed, 38 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index edf734f..c9034e8d 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2016-11-09 Segher Boessenkool <segher@kernel.crashing.org> + + * simplify-rtx.c (simplify_binary_operation_1): Simplify + (xor (and (xor A B) C) B) to (ior (and A C) (and B ~C)) and + (xor (and (xor A B) C) A) to (ior (and A ~C) (and B C)) if C + is a const_int. + 2016-11-09 David Malcolm <dmalcolm@redhat.com> * print-rtl-function.c: Include varasm.h. diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c index 5c3dea1..11a2e02 100644 --- a/gcc/simplify-rtx.c +++ b/gcc/simplify-rtx.c @@ -2886,6 +2886,37 @@ simplify_binary_operation_1 (enum rtx_code code, machine_mode mode, } } + /* If we have (xor (and (xor A B) C) A) with C a constant we can instead + do (ior (and A ~C) (and B C)) which is a machine instruction on some + machines, and also has shorter instruction path length. */ + if (GET_CODE (op0) == AND + && GET_CODE (XEXP (op0, 0)) == XOR + && CONST_INT_P (XEXP (op0, 1)) + && rtx_equal_p (XEXP (XEXP (op0, 0), 0), trueop1)) + { + rtx a = trueop1; + rtx b = XEXP (XEXP (op0, 0), 1); + rtx c = XEXP (op0, 1); + rtx nc = simplify_gen_unary (NOT, mode, c, mode); + rtx a_nc = simplify_gen_binary (AND, mode, a, nc); + rtx bc = simplify_gen_binary (AND, mode, b, c); + return simplify_gen_binary (IOR, mode, a_nc, bc); + } + /* Similarly, (xor (and (xor A B) C) B) as (ior (and A C) (and B ~C)) */ + else if (GET_CODE (op0) == AND + && GET_CODE (XEXP (op0, 0)) == XOR + && CONST_INT_P (XEXP (op0, 1)) + && rtx_equal_p (XEXP (XEXP (op0, 0), 1), trueop1)) + { + rtx a = XEXP (XEXP (op0, 0), 0); + rtx b = trueop1; + rtx c = XEXP (op0, 1); + rtx nc = simplify_gen_unary (NOT, mode, c, mode); + rtx b_nc = simplify_gen_binary (AND, mode, b, nc); + rtx ac = simplify_gen_binary (AND, mode, a, c); + return simplify_gen_binary (IOR, mode, ac, b_nc); + } + /* (xor (comparison foo bar) (const_int 1)) can become the reversed comparison if STORE_FLAG_VALUE is 1. */ if (STORE_FLAG_VALUE == 1 |