Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1737567

[PATCH] lib: zstd: make const array rtbTable static, reduces object code size

Show all headers | View raw

From: Colin Ian King <colin.king@canonical.com>

Don't populate const array rtbTable on the stack, instead make it
static. Also split overly long line to clean a chechkpach warning.
Makes the object code smaller by nearly 500 bytes:

Before:
   text	   data	    bss	    dec	    hex	filename
  13297	    104	      0	  13401	   3459	lib/zstd/fse_compress.o

After:
   text	   data	    bss	    dec	    hex	filename
  12742	    160	      0	  12902	   3266	lib/zstd/fse_compress.o

(gcc 6.3.0, x86-64)

Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 lib/zstd/fse_compress.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/zstd/fse_compress.c b/lib/zstd/fse_compress.c
index ef3d1741d532..f41c13128ed2 100644
--- a/lib/zstd/fse_compress.c
+++ b/lib/zstd/fse_compress.c
@@ -618,7 +618,10 @@ size_t FSE_normalizeCount(short *normalizedCounter, unsigned tableLog, const uns
 		return ERROR(GENERIC); /* Too small tableLog, compression potentially impossible */
 
 	{
-		U32 const rtbTable[] = {0, 473195, 504333, 520860, 550000, 700000, 750000, 830000};
+		U32 static const rtbTable[] = {
+			0, 473195, 504333, 520860,
+			550000, 700000, 750000, 830000
+		};
 		U64 const scale = 62 - tableLog;
 		U64 const step = div_u64((U64)1 << 62, (U32)total); /* <== here, one division ! */
 		U64 const vStep = 1ULL << (scale - 20);
-- 
2.14.1

Back to linux.kernel | Previous | Next — Next in thread | Find similar | Unroll thread

Thread

[PATCH] lib: zstd: make const array rtbTable static, reduces object code size Colin King <colin.king@canonical.com> - 2017-09-22 17:00 +0200
  Re: [PATCH] lib: zstd: make const array rtbTable static, reduces  object code size Nick Terrell <terrelln@fb.com> - 2017-09-22 21:20 +0200
    Re: [PATCH] lib: zstd: make const array rtbTable static, reduces  object code size Colin Ian King <colin.king@canonical.com> - 2017-09-22 23:40 +0200

csiph-web