From: Nathan Moinvaziri <nathan@nathanm.com>
Date: Sun, 13 Jun 2021 22:57:28 +0000 (-0700)
Subject: Reduce number of branches in partial chunk copy based on chunk size.
X-Git-Tag: 2.1.0-beta1~565
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=815faea92c3d32c71fb68d08e8cb227ed3364357;p=thirdparty%2Fzlib-ng.git

Reduce number of branches in partial chunk copy based on chunk size.
---

diff --git a/arch/arm/chunkset_neon.c b/arch/arm/chunkset_neon.c
index b15329827..22c3785c1 100644
--- a/arch/arm/chunkset_neon.c
+++ b/arch/arm/chunkset_neon.c
@@ -13,6 +13,8 @@
 
 typedef uint8x16_t chunk_t;
 
+#define CHUNK_SIZE 16
+
 #define HAVE_CHUNKMEMSET_1
 #define HAVE_CHUNKMEMSET_2
 #define HAVE_CHUNKMEMSET_4
diff --git a/arch/x86/chunkset_avx.c b/arch/x86/chunkset_avx.c
index eb76c0db9..7a9a56a09 100644
--- a/arch/x86/chunkset_avx.c
+++ b/arch/x86/chunkset_avx.c
@@ -9,6 +9,8 @@
 
 typedef __m256i chunk_t;
 
+#define CHUNK_SIZE 32
+
 #define HAVE_CHUNKMEMSET_1
 #define HAVE_CHUNKMEMSET_2
 #define HAVE_CHUNKMEMSET_4
diff --git a/arch/x86/chunkset_sse.c b/arch/x86/chunkset_sse.c
index 1d5a0faa9..d38e99dad 100644
--- a/arch/x86/chunkset_sse.c
+++ b/arch/x86/chunkset_sse.c
@@ -10,6 +10,8 @@
 
 typedef __m128i chunk_t;
 
+#define CHUNK_SIZE 16
+
 #define HAVE_CHUNKMEMSET_1
 #define HAVE_CHUNKMEMSET_2
 #define HAVE_CHUNKMEMSET_4
diff --git a/chunkset.c b/chunkset.c
index 2aa8d4e47..b07e6f482 100644
--- a/chunkset.c
+++ b/chunkset.c
@@ -14,6 +14,8 @@ typedef struct chunk_t { uint32_t u32[2]; } chunk_t;
 typedef struct chunk_t { uint8_t u8[8]; } chunk_t;
 #endif
 
+#define CHUNK_SIZE 8
+
 #define HAVE_CHUNKMEMSET_1
 #define HAVE_CHUNKMEMSET_4
 #define HAVE_CHUNKMEMSET_8
diff --git a/chunkset_tpl.h b/chunkset_tpl.h
index 62cd4aa78..2026ff37c 100644
--- a/chunkset_tpl.h
+++ b/chunkset_tpl.h
@@ -40,17 +40,20 @@ Z_INTERNAL uint8_t* CHUNKCOPY(uint8_t *out, uint8_t const *from, unsigned len) {
 Z_INTERNAL uint8_t* CHUNKCOPY_SAFE(uint8_t *out, uint8_t const *from, unsigned len, uint8_t *safe) {
     len = MIN(len, safe - out + 1);
     if (len < sizeof(chunk_t)) {
-        int32_t use_chunk16 = sizeof(chunk_t) > 16 && (len & 16);
-        if (use_chunk16) {
+#if CHUNK_SIZE > 16
+        if (len & 16) {
             memcpy(out, from, 16);
             out += 16;
             from += 16;
         }
+#endif
+#if CHUNK_SIZE > 8
         if (len & 8) {
             memcpy(out, from, 8);
             out += 8;
             from += 8;
         }
+#endif
         if (len & 4) {
             memcpy(out, from, 4);
             out += 4;