8316125: Windows call_stub unnecessarily saves xmm16-31 when UseAVX>=3

Reviewed-by: jvernee, kvn, sviswanathan

Author: djelinski

src/hotspot/cpu/x86/frame_x86.hpp

@@ -82,7 +82,7 @@
     // Entry frames
 #ifdef AMD64
 #ifdef _WIN64
-    entry_frame_after_call_words                     =  60,
+    entry_frame_after_call_words                     =  28,
     entry_frame_call_wrapper_offset                  =  2,
 
     arg_reg_save_area_bytes                          = 32, // Register argument save area

src/hotspot/cpu/x86/stubGenerator_x86_64.cpp

@@ -106,10 +106,8 @@
 //     [ return_from_Java     ] <--- rsp
 //     [ argument word n      ]
 //      ...
-// -60 [ argument word 1      ]
-// -59 [ saved xmm31          ] <--- rsp after_call
-//     [ saved xmm16-xmm30    ] (EVEX enabled, else the space is blank)
-// -27 [ saved xmm15          ]
+// -28 [ argument word 1      ]
+// -27 [ saved xmm15          ] <--- rsp after_call
 //     [ saved xmm7-xmm14     ]
 //  -9 [ saved xmm6           ] (each xmm register takes 2 slots)
 //  -7 [ saved r15            ]
@@ -137,7 +135,7 @@
 #ifdef _WIN64
 enum call_stub_layout {
   xmm_save_first     = 6,  // save from xmm6
-  xmm_save_last      = 31, // to xmm31
+  xmm_save_last      = 15, // to xmm15
   xmm_save_base      = -9,
   rsp_after_call_off = xmm_save_base - 2 * (xmm_save_last - xmm_save_first), // -27
   r15_off            = -7,
@@ -237,17 +235,8 @@ address StubGenerator::generate_call_stub(address& return_address) {
 
 #ifdef _WIN64
   int last_reg = 15;
-  if (UseAVX > 2) {
-    last_reg = 31;
-  }
-  if (VM_Version::supports_evex()) {
-    for (int i = xmm_save_first; i <= last_reg; i++) {
-      __ vextractf32x4(xmm_save(i), as_XMMRegister(i), 0);
-    }
-  } else {
-    for (int i = xmm_save_first; i <= last_reg; i++) {
-      __ movdqu(xmm_save(i), as_XMMRegister(i));
-    }
+  for (int i = xmm_save_first; i <= last_reg; i++) {
+    __ movdqu(xmm_save(i), as_XMMRegister(i));
   }
 
   const Address rdi_save(rbp, rdi_off * wordSize);
@@ -370,14 +359,8 @@ address StubGenerator::generate_call_stub(address& return_address) {
   // restore regs belonging to calling function
 #ifdef _WIN64
   // emit the restores for xmm regs
-  if (VM_Version::supports_evex()) {
-    for (int i = xmm_save_first; i <= last_reg; i++) {
-      __ vinsertf32x4(as_XMMRegister(i), as_XMMRegister(i), xmm_save(i), 0);
-    }
-  } else {
-    for (int i = xmm_save_first; i <= last_reg; i++) {
-      __ movdqu(as_XMMRegister(i), xmm_save(i));
-    }
+  for (int i = xmm_save_first; i <= last_reg; i++) {
+    __ movdqu(as_XMMRegister(i), xmm_save(i));
   }
 #endif
   __ movptr(r15, r15_save);

src/hotspot/cpu/x86/x86.ad

@@ -71,7 +71,7 @@ register %{
 //
 // Linux ABI:   No register preserved across function calls
 //              XMM0-XMM7 might hold parameters
-// Windows ABI: XMM6-XMM31 preserved across function calls
+// Windows ABI: XMM6-XMM15 preserved across function calls
 //              XMM0-XMM3 might hold parameters
 
 reg_def XMM0 ( SOC, SOC, Op_RegF, 0, xmm0->as_VMReg());