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8148328: aarch64: redundant lsr instructions in stub code.
authorfyang
Wed, 27 Jan 2016 12:20:53 +0800
changeset 35752 16265e7c7a53
parent 35751 6a057f120b11
child 35753 ee7921f045d2
8148328: aarch64: redundant lsr instructions in stub code. Summary: avoid redundant lsr instructions in jbyte_arraycopy and jbyte_disjoint_arraycopy. Reviewed-by: aph Contributed-by: felix.yang@linaro.org
hotspot/src/cpu/aarch64/vm/stubGenerator_aarch64.cpp file | annotate | diff | comparison | revisions 
--- a/hotspot/src/cpu/aarch64/vm/stubGenerator_aarch64.cpp	Thu Jan 28 08:33:45 2016 +0100
+++ b/hotspot/src/cpu/aarch64/vm/stubGenerator_aarch64.cpp	Wed Jan 27 12:20:53 2016 +0800
@@ -962,7 +962,7 @@
       __ lea(d, Address(d, count, Address::lsl(exact_log2(-step))));
     }
 
-    Label done, tail;
+    Label tail;
 
     __ cmp(count, 16/granularity);
     __ br(Assembler::LO, tail);
@@ -987,7 +987,8 @@
       }
       // rscratch2 is the byte adjustment needed to align s.
       __ cbz(rscratch2, aligned);
-      __ lsr(rscratch2, rscratch2, exact_log2(granularity));
+      int shift = exact_log2(granularity);
+      if (shift)  __ lsr(rscratch2, rscratch2, shift);
       __ sub(count, count, rscratch2);
 
 #if 0
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