linux-kernel - [PATCH] drm: sti: remove redundant sign extensions

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Message-Id: <1445001296-23029-1-git-send-email-linux@rasmusvillemoes.dk>
Date:	Fri, 16 Oct 2015 15:14:55 +0200
From:	Rasmus Villemoes <linux@...musvillemoes.dk>
To:	Benjamin Gaignard <benjamin.gaignard@...aro.org>,
	Vincent Abriou <vincent.abriou@...com>,
	David Airlie <airlied@...ux.ie>
Cc:	Rasmus Villemoes <linux@...musvillemoes.dk>,
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: [PATCH] drm: sti: remove redundant sign extensions

arg is long int, so arg = (arg << 22) >> 22 makes the upper 22 bits of
arg equal to bit 9 (or bit 41). But we then mask away all but bits 0-9, so
this is entirely redundant.

Signed-off-by: Rasmus Villemoes <linux@...musvillemoes.dk>
---
gcc seems to be smart enough to realize this - the generated code is
the same. This is thus just a tiny cleanup.

 drivers/gpu/drm/sti/sti_awg_utils.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/gpu/drm/sti/sti_awg_utils.c b/drivers/gpu/drm/sti/sti_awg_utils.c
index 6029a2e3db1d..00d0698be9d3 100644
--- a/drivers/gpu/drm/sti/sti_awg_utils.c
+++ b/drivers/gpu/drm/sti/sti_awg_utils.c
@@ -65,7 +65,6 @@ static int awg_generate_instr(enum opcode opcode,
 
 			mux = 0;
 			data_enable = 0;
-			arg = (arg << 22) >> 22;
 			arg &= (0x3ff);
 			break;
 		case REPEAT:
@@ -77,14 +76,12 @@ static int awg_generate_instr(enum opcode opcode,
 
 			mux = 0;
 			data_enable = 0;
-			arg = (arg << 22) >> 22;
 			arg &= (0x3ff);
 			break;
 		case JUMP:
 			mux = 0;
 			data_enable = 0;
 			arg |= 0x40; /* for jump instruction 7th bit is 1 */
-			arg = (arg << 22) >> 22;
 			arg &= 0x3ff;
 			break;
 		case STOP:
@@ -94,7 +91,6 @@ static int awg_generate_instr(enum opcode opcode,
 		case RPTSET:
 		case RPLSET:
 		case HOLD:
-			arg = (arg << 24) >> 24;
 			arg &= (0x0ff);
 			break;
 		default:
-- 
2.6.1

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