[Beignet] [PATCH 2/2] Skip spill/unspill instruction when trying to do spill.

[Ruiling Song]

We can only spill virtual registers, should skip physical register.
This fix random failure of compiler_box_blur when do spilling.

Signed-off-by: Ruiling Song <ruiling.song at intel.com>
---
 backend/src/backend/gen_insn_selection.cpp |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/backend/src/backend/gen_insn_selection.cpp b/backend/src/backend/gen_insn_selection.cpp
index 3610051..5cafa98 100644
--- a/backend/src/backend/gen_insn_selection.cpp
+++ b/backend/src/backend/gen_insn_selection.cpp
@@ -628,12 +628,15 @@ namespace gbe
 
     for (auto &block : blockList)
       for (auto &insn : block.insnList) {
+        // spill / unspill insn should be skipped when do spilling
+        if(insn.opcode == SEL_OP_SPILL_REG || insn.opcode == SEL_OP_UNSPILL_REG) continue;
+
         const uint32_t srcNum = insn.srcNum, dstNum = insn.dstNum;
 
         for (uint32_t srcID = 0; srcID < srcNum; ++srcID) {
           const GenRegister selReg = insn.src(srcID);
           const ir::Register reg = selReg.reg();
-          if(selReg.file == GEN_GENERAL_REGISTER_FILE && reg == spilledReg) {
+          if(reg == spilledReg && selReg.file == GEN_GENERAL_REGISTER_FILE && selReg.physical == 0) {
             GBE_ASSERT(srcID < 5);
             SelectionInstruction *unspill = this->create(SEL_OP_UNSPILL_REG, 1, 0);
             unspill->state  = GenInstructionState(simdWidth);
@@ -652,7 +655,7 @@ namespace gbe
         for (uint32_t dstID = 0; dstID < dstNum; ++dstID) {
           const GenRegister selReg = insn.dst(dstID);
           const ir::Register reg = selReg.reg();
-          if(selReg.file == GEN_GENERAL_REGISTER_FILE && reg == spilledReg) {
+          if(reg == spilledReg && selReg.file == GEN_GENERAL_REGISTER_FILE && selReg.physical == 0) {
             GBE_ASSERT(dstID < 5);
             SelectionInstruction *spill = this->create(SEL_OP_SPILL_REG, 0, 1);
             spill->state  = GenInstructionState(simdWidth);
-- 
1.7.9.5