Update GATHER instructions to support 2 read-write operands. Patch from myself and Manman Ren.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160110 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 14 insertions, 5 deletions

diff --git a/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp b/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp
index 52506fa..4a38324 100644
--- a/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp
+++ b/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp
@@ -572,8 +572,14 @@ void X86MCCodeEmitter::EmitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
   // Classify VEX_B, VEX_4V, VEX_R, VEX_X
   unsigned NumOps = Desc.getNumOperands();
   unsigned CurOp = 0;
-  if (NumOps > 1 && Desc.getOperandConstraint(1, MCOI::TIED_TO) != -1)
+  if (NumOps > 1 && Desc.getOperandConstraint(1, MCOI::TIED_TO) == 0)
     ++CurOp;
+  else if (NumOps > 3 && Desc.getOperandConstraint(2, MCOI::TIED_TO) == 0) {
+    assert(Desc.getOperandConstraint(NumOps - 1, MCOI::TIED_TO) == 1);
+    // Special case for GATHER with 2 TIED_TO operands
+    // Skip the first 2 operands: dst, mask_wb
+    CurOp += 2;
+  }
 
   switch (TSFlags & X86II::FormMask) {
   case X86II::MRMInitReg: llvm_unreachable("FIXME: Remove this!");
@@ -971,11 +977,14 @@ EncodeInstruction(const MCInst &MI, raw_ostream &OS,
   // FIXME: This should be handled during MCInst lowering.
   unsigned NumOps = Desc.getNumOperands();
   unsigned CurOp = 0;
-  if (NumOps > 1 && Desc.getOperandConstraint(1, MCOI::TIED_TO) != -1)
+  if (NumOps > 1 && Desc.getOperandConstraint(1, MCOI::TIED_TO) == 0)
     ++CurOp;
-  else if (NumOps > 2 && Desc.getOperandConstraint(NumOps-1, MCOI::TIED_TO)== 0)
-    // Skip the last source operand that is tied_to the dest reg. e.g. LXADD32
-    --NumOps;
+  else if (NumOps > 3 && Desc.getOperandConstraint(2, MCOI::TIED_TO) == 0) {
+    assert(Desc.getOperandConstraint(NumOps - 1, MCOI::TIED_TO) == 1);
+    // Special case for GATHER with 2 TIED_TO operands
+    // Skip the first 2 operands: dst, mask_wb
+    CurOp += 2;
+  }
 
   // Keep track of the current byte being emitted.
   unsigned CurByte = 0;