- Avoid the longer SIB encoding on x86_64 when it's not needed.
- Synchronize instruction length computation code in X86InstrInfo with code in X86CodeEmitter.cpp
Patch by Zoltan Varga.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70929 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86CodeEmitter.cpp b/lib/Target/X86/X86CodeEmitter.cpp
index c54a996..e0396cf 100644
--- a/lib/Target/X86/X86CodeEmitter.cpp
+++ b/lib/Target/X86/X86CodeEmitter.cpp
@@ -338,8 +338,8 @@
   unsigned BaseReg = Base.getReg();
 
   // Is a SIB byte needed?
-  if ((!Is64BitMode || DispForReloc) && IndexReg.getReg() == 0 &&
-      (BaseReg == 0 || getX86RegNum(BaseReg) != N86::ESP)) {
+  if (IndexReg.getReg() == 0 && (!Is64BitMode || BaseReg != 0) && 
+      (BaseReg == 0 || getX86RegNum(BaseReg) != N86::ESP)) {      
     if (BaseReg == 0) {  // Just a displacement?
       // Emit special case [disp32] encoding
       MCE.emitByte(ModRMByte(0, RegOpcodeField, 5));