From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
To: Roland Dreier <roland@kernel.org>,
Sean Hefty <sean.hefty@intel.com>,
Hal Rosenstock <hal.rosenstock@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>,
linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 2/2] infiniband: Use unsigned for bit index
Date: Fri, 16 Jan 2015 15:39:56 +0100 [thread overview]
Message-ID: <1421419196-4659-2-git-send-email-linux@rasmusvillemoes.dk> (raw)
In-Reply-To: <1421419196-4659-1-git-send-email-linux@rasmusvillemoes.dk>
In the expressions idx/32 and idx%32, both idx and 32 have signed
type, and unfortunately the C standard prescribes rounding to 0, so
unless gcc can prove that idx is non-negative, these cannot be
implemented as simple shift respectively mask operations. Help gcc by
changing the type of idx to unsigned - this cuts another few
instructions from the generated code.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
drivers/infiniband/hw/ocrdma/ocrdma_verbs.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c b/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c
index eff11e6c6183..61c3047f5170 100644
--- a/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c
+++ b/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c
@@ -1479,10 +1479,10 @@ mbx_err:
return status;
}
-static void ocrdma_srq_toggle_bit(struct ocrdma_srq *srq, int idx)
+static void ocrdma_srq_toggle_bit(struct ocrdma_srq *srq, unsigned int idx)
{
- int i = idx / 32;
- unsigned int mask = (1 << (idx % 32));
+ unsigned int i = idx / 32;
+ u32 mask = (1U << (idx % 32));
srq->idx_bit_fields[i] ^= mask;
}
--
2.1.3
next prev parent reply other threads:[~2015-01-16 14:39 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-16 14:39 [PATCH 1/2] infiniband: Help gcc generate better code for ocrdma_srq_toggle_bit Rasmus Villemoes
2015-01-16 14:39 ` Rasmus Villemoes [this message]
[not found] ` <1421419196-4659-2-git-send-email-linux-qQsb+v5E8BnlAoU/VqSP6n9LOBIZ5rWg@public.gmane.org>
2015-02-02 12:03 ` [PATCH 2/2] infiniband: Use unsigned for bit index Selvin Xavier
[not found] ` <1421419196-4659-1-git-send-email-linux-qQsb+v5E8BnlAoU/VqSP6n9LOBIZ5rWg@public.gmane.org>
2015-01-30 23:00 ` [PATCH 1/2] infiniband: Help gcc generate better code for ocrdma_srq_toggle_bit Rasmus Villemoes
[not found] ` <87twz7ho25.fsf-qQsb+v5E8BnlAoU/VqSP6n9LOBIZ5rWg@public.gmane.org>
2015-01-31 11:07 ` Yann Droneaud
[not found] ` <1422702466.3030.4.camel-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org>
2015-02-02 12:58 ` Selvin Xavier
2015-02-02 12:04 ` Selvin Xavier
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