Mercurial > hg > truffle

diff src/share/vm/opto/vectornode.cpp @ 6893:b2c669fd8114

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
8001183: incorrect results of char vectors right shift operaiton Summary: do vector right shift operation for small int types only after loads Reviewed-by: jrose, dlong
author kvn
date Tue, 23 Oct 2012 13:06:37 -0700
parents aaeb9add1ab3
children
line wrap: on
line diff
--- a/src/share/vm/opto/vectornode.cpp	Mon Oct 22 16:56:03 2012 -0700
+++ b/src/share/vm/opto/vectornode.cpp	Tue Oct 23 13:06:37 2012 -0700
@@ -103,9 +103,9 @@
     return Op_LShiftVL;
   case Op_RShiftI:
     switch (bt) {
-    case T_BOOLEAN:
+    case T_BOOLEAN:return Op_URShiftVB; // boolean is unsigned value
+    case T_CHAR:   return Op_URShiftVS; // char is unsigned value
     case T_BYTE:   return Op_RShiftVB;
-    case T_CHAR:
     case T_SHORT:  return Op_RShiftVS;
     case T_INT:    return Op_RShiftVI;
     }
@@ -115,10 +115,14 @@
     return Op_RShiftVL;
   case Op_URShiftI:
     switch (bt) {
-    case T_BOOLEAN:
-    case T_BYTE:   return Op_URShiftVB;
-    case T_CHAR:
-    case T_SHORT:  return Op_URShiftVS;
+    case T_BOOLEAN:return Op_URShiftVB;
+    case T_CHAR:   return Op_URShiftVS;
+    case T_BYTE:
+    case T_SHORT:  return 0; // Vector logical right shift for signed short
+                             // values produces incorrect Java result for
+                             // negative data because java code should convert
+                             // a short value into int value with sign
+                             // extension before a shift.
     case T_INT:    return Op_URShiftVI;
     }
     ShouldNotReachHere();