emitIAS for movsx and movzx.

src/IceTargetLoweringX8632.cpp

 //===- subzero/src/IceTargetLoweringX8632.cpp - x86-32 lowering -----------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the TargetLoweringX8632 class, which
@@ skipping 2000 matching lines @@
       }
       if (Src0RM->getType() == IceType_i1) {
         Constant *One = Ctx->getConstantInt32(IceType_i32, 1);
         _and(Tmp, One);
       }
       _mov(DestLo, Tmp);
       _mov(DestHi, Zero);
     } else if (Src0RM->getType() == IceType_i1) {
       // t = Src0RM; t &= 1; Dest = t
       Constant *One = Ctx->getConstantInt32(IceType_i32, 1);
-      Variable *T = makeReg(IceType_i32);
-      _movzx(T, Src0RM);
+      Type DestTy = Dest->getType();
+      Variable *T;
+      if (DestTy == IceType_i8) {
+        T = makeReg(DestTy);
+        _mov(T, Src0RM);
+      } else {
+        // Use 32-bit for both 16-bit and 32-bit, since 32-bit ops are shorter.
+        T = makeReg(IceType_i32);
+        _movzx(T, Src0RM);
+      }
       _and(T, One);
       _mov(Dest, T);
     } else {
       // t1 = movzx src; dst = t1
       Variable *T = makeReg(Dest->getType());
       _movzx(T, Src0RM);
       _mov(Dest, T);
     }
     break;
   }
@@ skipping 2484 matching lines @@
   } else if (IsConstant || IsExternal)
     Str << "\t.zero\t" << Size << "\n";
   // Size is part of .comm.
 
   if (IsConstant || HasInitializer || IsExternal)
     Str << "\t.size\t" << MangledName << ", " << Size << "\n";
   // Size is part of .comm.
 }
 
 } // end of namespace Ice