hotspot/src/cpu/x86/vm/stubGenerator_x86_32.cpp

rev 7347 : 8078113: 8011102 changes may cause incorrect results
Summary: replace Vzeroupper instruction in stubs with zeroing only used ymm registers.
Reviewed-by: kvn
Contributed-by: sandhya.viswanathan@intel.com

@@ -835,11 +835,12 @@
     __ subl(qword_count, 8);
     __ jcc(Assembler::greaterEqual, L_copy_64_bytes_loop);
 
     if (UseUnalignedLoadStores && (UseAVX >= 2)) {
       // clean upper bits of YMM registers
-      __ vzeroupper();
+      __ vpxor(xmm0, xmm0);
+      __ vpxor(xmm1, xmm1);
     }
     __ addl(qword_count, 8);
     __ jccb(Assembler::zero, L_exit);
     //
     // length is too short, just copy qwords