1 files changed, 12 insertions, 3 deletions
diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp
index 9d304b52db..a402a382c8 100644
--- a/lib/Target/X86/X86InstrInfo.cpp
+++ b/lib/Target/X86/X86InstrInfo.cpp
@@ -126,15 +126,24 @@ MachineInstr *X86InstrInfo::convertToThreeAddress(MachineInstr *MI) const {
 ///
 MachineInstr *X86InstrInfo::commuteInstruction(MachineInstr *MI) const {
   switch (MI->getOpcode()) {
+  case X86::SHRD16rri8: // A = SHRD16rri8 B, C, I -> A = SHLD16rri8 C, B, (16-I)
+  case X86::SHLD16rri8: // A = SHLD16rri8 B, C, I -> A = SHRD16rri8 C, B, (16-I)
   case X86::SHRD32rri8: // A = SHRD32rri8 B, C, I -> A = SHLD32rri8 C, B, (32-I)
   case X86::SHLD32rri8:{// A = SHLD32rri8 B, C, I -> A = SHRD32rri8 C, B, (32-I)
+    unsigned Opc;
+    unsigned Size;
+    switch (MI->getOpcode()) {
+    default: assert(0 && "Unreachable!");
+    case X86::SHRD16rri8: Size = 16; Opc = X86::SHLD16rri8; break;
+    case X86::SHLD16rri8: Size = 16; Opc = X86::SHRD16rri8; break;
+    case X86::SHRD32rri8: Size = 32; Opc = X86::SHLD32rri8; break;
+    case X86::SHLD32rri8: Size = 32; Opc = X86::SHRD32rri8; break;
+    }
     unsigned Amt = MI->getOperand(3).getImmedValue();
     unsigned A = MI->getOperand(0).getReg();
     unsigned B = MI->getOperand(1).getReg();
     unsigned C = MI->getOperand(2).getReg();
-    unsigned Opc = X86::SHRD32rri8;
-    if (MI->getOpcode() == X86::SHRD32rri8) Opc = X86::SHLD32rri8;
-    return BuildMI(Opc, 3, A).addReg(B).addReg(C).addImm(32-Amt);
+    return BuildMI(Opc, 3, A).addReg(B).addReg(C).addImm(Size-Amt);
   }
   default:
     return TargetInstrInfo::commuteInstruction(MI);