From 9dc405d410a60ed06715c321f418041608c0ef45 Mon Sep 17 00:00:00 2001 From: Kyrylo Tkachov Date: Wed, 9 Oct 2024 09:39:55 -0700 Subject: [PATCH 1/2] PR 117048: simplify-rtx: Extend (x << C1) | (X >> C2) --> ROTATE transformation to vector operands In the testcase from patch [2/2] we want to match a vector rotate operate from an IOR of left and right shifts by immediate. simplify-rtx has code for just that but it looks like it's prepared to do handle only scalar operands. In practice most of the code works for vector modes as well except the shift amounts are checked to be CONST_INT rather than vector constants that we have here. This is easily extended by using unwrap_const_vec_duplicate to extract the repeating constant shift amount. With this change combine now tries matching the simpler and expected: (set (reg:V2DI 119 [ _14 ]) (rotate:V2DI (xor:V2DI (reg:V2DI 114 [ vect__1.12_16 ]) (reg:V2DI 116 [ *m1_01_8(D) ])) (const_vector:V2DI [ (const_int 32 [0x20]) repeated x2 ]))) instead of the previous: (set (reg:V2DI 119 [ _14 ]) (ior:V2DI (ashift:V2DI (xor:V2DI (reg:V2DI 114 [ vect__1.12_16 ]) (reg:V2DI 116 [ *m1_01_8(D) ])) (const_vector:V2DI [ (const_int 32 [0x20]) repeated x2 ])) (lshiftrt:V2DI (xor:V2DI (reg:V2DI 114 [ vect__1.12_16 ]) (reg:V2DI 116 [ *m1_01_8(D) ])) (const_vector:V2DI [ (const_int 32 [0x20]) repeated x2 ])))) To actually fix the PR the aarch64 backend needs some adjustment as well which is done in patch [2/2], which adds the testcase as well. Bootstrapped and tested on aarch64-none-linux-gnu. Signed-off-by: Kyrylo Tkachov PR target/117048 * simplify-rtx.cc (simplify_context::simplify_binary_operation_1): Handle vector constants in (x << C1) | (x >> C2) -> ROTATE simplification. --- gcc/simplify-rtx.cc | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc index e8e60404ef6..7ff14594daa 100644 --- a/gcc/simplify-rtx.cc +++ b/gcc/simplify-rtx.cc @@ -3477,12 +3477,16 @@ simplify_context::simplify_binary_operation_1 (rtx_code code, } if (GET_CODE (opleft) == ASHIFT && GET_CODE (opright) == LSHIFTRT - && rtx_equal_p (XEXP (opleft, 0), XEXP (opright, 0)) - && CONST_INT_P (XEXP (opleft, 1)) - && CONST_INT_P (XEXP (opright, 1)) - && (INTVAL (XEXP (opleft, 1)) + INTVAL (XEXP (opright, 1)) + && rtx_equal_p (XEXP (opleft, 0), XEXP (opright, 0))) + { + rtx leftcst = unwrap_const_vec_duplicate (XEXP (opleft, 1)); + rtx rightcst = unwrap_const_vec_duplicate (XEXP (opright, 1)); + + if (CONST_INT_P (leftcst) && CONST_INT_P (rightcst) + && (INTVAL (leftcst) + INTVAL (rightcst) == GET_MODE_UNIT_PRECISION (mode))) - return gen_rtx_ROTATE (mode, XEXP (opright, 0), XEXP (opleft, 1)); + return gen_rtx_ROTATE (mode, XEXP (opright, 0), XEXP (opleft, 1)); + } /* Same, but for ashift that has been "simplified" to a wider mode by simplify_shift_const. */ -- 2.44.0