Merge pull request #1226 from Nicoshev/reduce_cpy_variable_usage

Reduce usage of variable cpy on decompression

GitOrigin-RevId: 76106cba6fbbf8efb63d9fa90f052d384d212c56
Change-Id: I32f37a2de82af922df98f942355a74bee0587918

lib/lz4.c

diff --git a/lib/lz4.c b/lib/lz4.c
index 0982f95..ff5c8f9 100644
--- a/lib/lz4.c
+++ b/lib/lz4.c
@@ -2025,19 +2025,18 @@
                 if (unlikely((uptrval)(ip)+length<(uptrval)(ip))) { goto _output_error; } /* overflow detection */
 
                 /* copy literals */
-                cpy = op+length;
                 LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH);
-                if ((cpy>oend-32) || (ip+length>iend-32)) { goto safe_literal_copy; }
-                LZ4_wildCopy32(op, ip, cpy);
-                ip += length; op = cpy;
-            } else {
-                cpy = op+length;
-                DEBUGLOG(7, "copy %u bytes in a 16-bytes stripe", (unsigned)length);
+                if ((op+length>oend-32) || (ip+length>iend-32)) { goto safe_literal_copy; }
+                LZ4_wildCopy32(op, ip, op+length);
+                ip += length; op += length;
+            } else if (ip <= iend-(16 + 1/*max lit + offset + nextToken*/)) {
                 /* We don't need to check oend, since we check it once for each loop below */
-                if (ip > iend-(16 + 1/*max lit + offset + nextToken*/)) { goto safe_literal_copy; }
+                DEBUGLOG(7, "copy %u bytes in a 16-bytes stripe", (unsigned)length);
                 /* Literals can only be <= 14, but hope compilers optimize better when copy by a register size */
                 LZ4_memcpy(op, ip, 16);
-                ip += length; op = cpy;
+                ip += length; op += length;
+            } else {
+                goto safe_literal_copy;
             }
 
             /* get offset */
@@ -2194,11 +2193,12 @@
                 if (unlikely((uptrval)(ip)+length<(uptrval)(ip))) { goto _output_error; } /* overflow detection */
             }
 
-            /* copy literals */
-            cpy = op+length;
 #if LZ4_FAST_DEC_LOOP
         safe_literal_copy:
 #endif
+            /* copy literals */
+            cpy = op+length;
+
             LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH);
             if ((cpy>oend-MFLIMIT) || (ip+length>iend-(2+1+LASTLITERALS))) {
                 /* We've either hit the input parsing restriction or the output parsing restriction.