[optimize.d] use early returns

compiler/src/dmd/optimize.d

@@ -79,103 +79,106 @@ Expression expandVar(int result, VarDeclaration v)
  return nullReturn();
  if (!v.originalType && v.semanticRun < PASS.semanticdone) // semantic() not yet run
  v.dsymbolSemantic(null);
- if (v.type &&
- (v.isConst() || v.isImmutable() || v.storage_class & STC.manifest))
+ if (!v.type)
+ nullReturn();
+
+ if ((!v.isConst() && !v.isImmutable() && !(v.storage_class & STC.manifest)))
+ nullReturn();
+
+ Type tb = v.type.toBasetype();
+ if (v.storage_class & STC.manifest ||
+ tb.isScalar() ||
+ ((result & WANTexpand) && (tb.ty != Tsarray && tb.ty != Tstruct)))
  {
- Type tb = v.type.toBasetype();
- if (v.storage_class & STC.manifest ||
- tb.isScalar() ||
- ((result & WANTexpand) && (tb.ty != Tsarray && tb.ty != Tstruct)))
+ if (v._init)
  {
- if (v._init)
+ if (v.inuse)
  {
- if (v.inuse)
+ if (v.storage_class & STC.manifest)
  {
- if (v.storage_class & STC.manifest)
- {
- .error(v.loc, "%s `%s` recursive initialization of constant", v.kind, v.toPrettyChars);
- return errorReturn();
- }
- return nullReturn();
+ .error(v.loc, "%s `%s` recursive initialization of constant", v.kind, v.toPrettyChars);
+ return errorReturn();
  }
- Expression ei = v.getConstInitializer();
- if (!ei)
+ return nullReturn();
+ }
+ Expression ei = v.getConstInitializer();
+ if (!ei)
+ {
+ if (v.storage_class & STC.manifest)
  {
- if (v.storage_class & STC.manifest)
- {
- .error(v.loc, "%s `%s` enum cannot be initialized with `%s`", v.kind, v.toPrettyChars, dmd.hdrgen.toChars(v._init));
- return errorReturn();
- }
- return nullReturn();
+ .error(v.loc, "%s `%s` enum cannot be initialized with `%s`", v.kind, v.toPrettyChars, dmd.hdrgen.toChars(v._init));
+ return errorReturn();
  }
- if (ei.op == EXP.construct || ei.op == EXP.blit)
+ return nullReturn();
+ }
+ if (ei.op == EXP.construct || ei.op == EXP.blit)
+ {
+ auto ae = cast(AssignExp)ei;
+ ei = ae.e2;
+ if (ei.isConst() == 1)
  {
- auto ae = cast(AssignExp)ei;
- ei = ae.e2;
- if (ei.isConst() == 1)
- {
- }
- else if (ei.op == EXP.string_)
- {
- // https://issues.dlang.org/show_bug.cgi?id=14459
- // Do not constfold the string literal
- // if it's typed as a C string, because the value expansion
- // will drop the pointer identity.
- if (!(result & WANTexpand) && ei.type.toBasetype().ty == Tpointer)
- return nullReturn();
- }
- else
- return nullReturn();
- if (ei.type == v.type)
- {
- // const variable initialized with const expression
- }
- else if (ei.implicitConvTo(v.type) >= MATCH.constant)
- {
- // const var initialized with non-const expression
- ei = ei.implicitCastTo(null, v.type);
- ei = ei.expressionSemantic(null);
- }
- else
- return nullReturn();
  }
- else if (!(v.storage_class & STC.manifest) &&
- ei.isConst() != 1 &&
- ei.op != EXP.string_ &&
- ei.op != EXP.address)
+ else if (ei.op == EXP.string_)
  {
- return nullReturn();
+ // https://issues.dlang.org/show_bug.cgi?id=14459
+ // Do not constfold the string literal
+ // if it's typed as a C string, because the value expansion
+ // will drop the pointer identity.
+ if (!(result & WANTexpand) && ei.type.toBasetype().ty == Tpointer)
+ return nullReturn();
  }
-
- if (!ei.type)
- {
+ else
  return nullReturn();
+ if (ei.type == v.type)
+ {
+ // const variable initialized with const expression
  }
- else
+ else if (ei.implicitConvTo(v.type) >= MATCH.constant)
  {
- // Should remove the copy() operation by
- // making all mods to expressions copy-on-write
- return initializerReturn(ei.copy());
+ // const var initialized with non-const expression
+ ei = ei.implicitCastTo(null, v.type);
+ ei = ei.expressionSemantic(null);
  }
+ else
+ return nullReturn();
+ }
+ else if (!(v.storage_class & STC.manifest) &&
+ ei.isConst() != 1 &&
+ ei.op != EXP.string_ &&
+ ei.op != EXP.address)
+ {
+ return nullReturn();
+ }
+
+ if (!ei.type)
+ {
+ return nullReturn();
  }
  else
  {
- // v does not have an initializer
- version (all)
- {
- return nullReturn();
- }
- else
- {
- // BUG: what if const is initialized in constructor?
- auto e = v.type.defaultInit();
- e.loc = e1.loc;
- return initializerReturn(e);
- }
+ // Should remove the copy() operation by
+ // making all mods to expressions copy-on-write
+ return initializerReturn(ei.copy());
  }
- assert(0);
  }
+ else
+ {
+ // v does not have an initializer
+ version (all)
+ {
+ return nullReturn();
+ }
+ else
+ {
+ // BUG: what if const is initialized in constructor?
+ auto e = v.type.defaultInit();
+ e.loc = e1.loc;
+ return initializerReturn(e);
+ }
+ }
+ assert(0);
  }
+
  return nullReturn();
 }