1 files changed, 29 insertions, 8 deletions

diff --git a/llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp b/llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp
index a152f7e963e..54a90f13a80 100644
--- a/llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp
+++ b/llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp
@@ -535,6 +535,7 @@ void X86MCCodeEmitter::EmitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
   bool HasVEX_4V = (TSFlags >> X86II::VEXShift) & X86II::VEX_4V;
   bool HasVEX_4VOp3 = (TSFlags >> X86II::VEXShift) & X86II::VEX_4VOp3;
   bool HasMemOp4 = (TSFlags >> X86II::VEXShift) & X86II::MemOp4;
+  bool HasEVEX_RC = false;
 
   // VEX_R: opcode externsion equivalent to REX.R in
   // 1's complement (inverted) form
@@ -610,6 +611,9 @@ void X86MCCodeEmitter::EmitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
   // EVEX_b
   unsigned char EVEX_b = 0;
 
+  // EVEX_rc
+  unsigned char EVEX_rc = 0;
+
   // EVEX_aaa
   unsigned char EVEX_aaa = 0;
 
@@ -676,6 +680,7 @@ void X86MCCodeEmitter::EmitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
 
   // Classify VEX_B, VEX_4V, VEX_R, VEX_X
   unsigned NumOps = Desc.getNumOperands();
+  unsigned RcOperand = NumOps-1;
   unsigned CurOp = 0;
   if (NumOps > 1 && Desc.getOperandConstraint(1, MCOI::TIED_TO) == 0)
     ++CurOp;
@@ -834,7 +839,12 @@ void X86MCCodeEmitter::EmitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
       VEX_X = 0x0;
     CurOp++;
     if (HasVEX_4VOp3)
-      VEX_4V = getVEXRegisterEncoding(MI, CurOp);
+      VEX_4V = getVEXRegisterEncoding(MI, CurOp++);
+    if (EVEX_b) {
+      assert(RcOperand >= CurOp);
+      EVEX_rc = MI.getOperand(RcOperand).getImm() & 0x3;
+      HasEVEX_RC = true;
+    }
     break;
   case X86II::MRMDestReg:
     // MRMDestReg instructions forms:
@@ -934,12 +944,19 @@ void X86MCCodeEmitter::EmitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
              (VEX_4V  << 3) |
              (EVEX_U  << 2) |
              VEX_PP, CurByte, OS);
-    EmitByte((EVEX_z  << 7) |
-             (EVEX_L2 << 6) |
-             (VEX_L   << 5) |
-             (EVEX_b  << 4) |
-             (EVEX_V2 << 3) |
-             EVEX_aaa, CurByte, OS);
+    if (HasEVEX_RC)
+      EmitByte((EVEX_z  << 7) |
+              (EVEX_rc << 5) |
+              (EVEX_b  << 4) |
+              (EVEX_V2 << 3) |
+              EVEX_aaa, CurByte, OS);
+    else
+      EmitByte((EVEX_z  << 7) |
+              (EVEX_L2 << 6) |
+              (VEX_L   << 5) |
+              (EVEX_b  << 4) |
+              (EVEX_V2 << 3) |
+              EVEX_aaa, CurByte, OS);
   }
 }
 
@@ -1206,7 +1223,8 @@ EncodeInstruction(const MCInst &MI, raw_ostream &OS,
   // It uses the EVEX.aaa field?
   bool HasEVEX = (TSFlags >> X86II::VEXShift) & X86II::EVEX;
   bool HasEVEX_K = HasEVEX && ((TSFlags >> X86II::VEXShift) & X86II::EVEX_K);
-
+  bool HasEVEX_B = HasEVEX && ((TSFlags >> X86II::VEXShift) & X86II::EVEX_B);
+  
   // Determine where the memory operand starts, if present.
   int MemoryOperand = X86II::getMemoryOperandNo(TSFlags, Opcode);
   if (MemoryOperand != -1) MemoryOperand += CurOp;
@@ -1302,6 +1320,9 @@ EncodeInstruction(const MCInst &MI, raw_ostream &OS,
     CurOp = HasMemOp4 ? SrcRegNum : SrcRegNum + 1;
     if (HasVEX_4VOp3)
       ++CurOp;
+    // do not count the rounding control operand
+    if (HasEVEX_B)
+      NumOps--;
     break;
 
   case X86II::MRMSrcMem: {