Subzero: Fix a crash in mem operand dumping.

src/IceInstX8632.cpp

 //===- subzero/src/IceInstX8632.cpp - X86-32 instruction implementation ---===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 171 matching lines @@
     if (getBase())
       Str << "+";
     if (getShift() > 0)
       Str << (1u << getShift()) << "*";
     if (Func)
       getIndex()->dump(Func);
     else
       getIndex()->dump(Str);
     Dumped = true;
   }
+  if (Disp) {
+    if (Disp > 0)
+      Str << "+";
+    Str << Disp;
+    Dumped = true;
+  }
   // Pretty-print the Offset.
   bool OffsetIsZero = false;
   bool OffsetIsNegative = false;
-  if (getOffset() == 0 && Disp == 0) {
+  if (getOffset() == nullptr) {
     OffsetIsZero = true;
-  } else if (getOffset() == 0 && Disp != 0) {
-    OffsetIsZero = (Disp == 0);
-    OffsetIsNegative = (Disp < 0);
   } else if (const auto *CI = llvm::dyn_cast<ConstantInteger32>(getOffset())) {
-    OffsetIsZero = (CI->getValue() + Disp == 0);
-    OffsetIsNegative = (static_cast<int32_t>(CI->getValue()) + Disp < 0);
+    OffsetIsZero = (CI->getValue() == 0);
+    OffsetIsNegative = (static_cast<int32_t>(CI->getValue()) < 0);
   } else {
-    assert(llvm::isa<ConstantRelocatable>(getOffset()) && Disp == 0);
+    assert(llvm::isa<ConstantRelocatable>(getOffset()));
   }
   if (Dumped) {
     if (!OffsetIsZero) {     // Suppress if Offset is known to be 0
       if (!OffsetIsNegative) // Suppress if Offset is known to be negative
         Str << "+";
       getOffset()->dump(Func, Str);
     }
   } else {
     // There is only the offset.
     getOffset()->dump(Func, Str);
@@ skipping 99 matching lines @@
     Var->dump(Func);
   else
     Var->dump(Str);
   Str << ")";
 }
 
 } // namespace X86Internal
 } // end of namespace Ice
 
 X86INSTS_DEFINE_STATIC_DATA(TargetX8632)