From 0c586913e61021681e3221e8760cd87b24142aea Mon Sep 17 00:00:00 2001 From: Roger Sayle Date: Wed, 24 Jun 2020 19:18:03 +0000 Subject: [PATCH] simplify-rtx: Simplify rotates by zero 2020-06-24 Roger Sayle Segher Boessenkool * simplify-rtx.c (simplify_unary_operation_1): Simplify rotates by 0. --- gcc/simplify-rtx.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c index 65008eaab45..3e913b5dd4f 100644 --- a/gcc/simplify-rtx.c +++ b/gcc/simplify-rtx.c @@ -3645,6 +3645,8 @@ simplify_binary_operation_1 (enum rtx_code code, machine_mode mode, case ROTATERT: case ROTATE: + if (trueop1 == CONST0_RTX (mode)) + return op0; /* Canonicalize rotates by constant amount. If op1 is bitsize / 2, prefer left rotation, if op1 is from bitsize / 2 + 1 to bitsize - 1, use other direction of rotate with 1 .. bitsize / 2 - 1 -- 2.30.2