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optimize.d
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optimize.d
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/**
* Compiler implementation of the
* $(LINK2 http://www.dlang.org, D programming language).
*
* Copyright: Copyright (C) 1999-2018 by The D Language Foundation, All Rights Reserved
* Authors: $(LINK2 http://www.digitalmars.com, Walter Bright)
* License: $(LINK2 http://www.boost.org/LICENSE_1_0.txt, Boost License 1.0)
* Source: $(LINK2 https://github.com/dlang/dmd/blob/master/src/dmd/optimize.d, _optimize.d)
* Documentation: https://dlang.org/phobos/dmd_optimize.html
* Coverage: https://codecov.io/gh/dlang/dmd/src/master/src/dmd/optimize.d
*/
module dmd.optimize;
import core.stdc.stdio;
import dmd.constfold;
import dmd.ctfeexpr;
import dmd.dclass;
import dmd.declaration;
import dmd.dsymbol;
import dmd.dsymbolsem;
import dmd.expression;
import dmd.expressionsem;
import dmd.globals;
import dmd.init;
import dmd.mtype;
import dmd.root.ctfloat;
import dmd.sideeffect;
import dmd.tokens;
import dmd.visitor;
/*************************************
* If variable has a const initializer,
* return that initializer.
* Returns:
* initializer if there is one,
* null if not,
* ErrorExp if error
*/
Expression expandVar(int result, VarDeclaration v)
{
//printf("expandVar(result = %d, v = %p, %s)\n", result, v, v ? v.toChars() : "null");
/********
* Params:
* e = initializer expression
*/
Expression initializerReturn(Expression e)
{
if (e.type != v.type)
{
e = e.castTo(null, v.type);
}
v.inuse++;
e = e.optimize(result);
v.inuse--;
//if (e) printf("\te = %p, %s, e.type = %d, %s\n", e, e.toChars(), e.type.ty, e.type.toChars());
return e;
}
static Expression nullReturn()
{
return null;
}
static Expression errorReturn()
{
return new ErrorExp();
}
if (!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))
{
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.inuse)
{
if (v.storage_class & STC.manifest)
{
v.error("recursive initialization of constant");
return errorReturn();
}
return nullReturn();
}
Expression ei = v.getConstInitializer();
if (!ei)
{
if (v.storage_class & STC.manifest)
{
v.error("enum cannot be initialized with `%s`", v._init.toChars());
return errorReturn();
}
return nullReturn();
}
if (ei.op == TOK.construct || ei.op == TOK.blit)
{
AssignExp ae = cast(AssignExp)ei;
ei = ae.e2;
if (ei.isConst() == 1)
{
}
else if (ei.op == TOK.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 != TOK.string_ &&
ei.op != TOK.address)
{
return nullReturn();
}
if (!ei.type)
{
return nullReturn();
}
else
{
// Should remove the copy() operation by
// making all mods to expressions copy-on-write
return initializerReturn(ei.copy());
}
}
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();
}
private Expression fromConstInitializer(int result, Expression e1)
{
//printf("fromConstInitializer(result = %x, %s)\n", result, e1.toChars());
//static int xx; if (xx++ == 10) assert(0);
Expression e = e1;
if (e1.op == TOK.variable)
{
VarExp ve = cast(VarExp)e1;
VarDeclaration v = ve.var.isVarDeclaration();
e = expandVar(result, v);
if (e)
{
// If it is a comma expression involving a declaration, we mustn't
// perform a copy -- we'd get two declarations of the same variable.
// See bugzilla 4465.
if (e.op == TOK.comma && (cast(CommaExp)e).e1.op == TOK.declaration)
e = e1;
else if (e.type != e1.type && e1.type && e1.type.ty != Tident)
{
// Type 'paint' operation
e = e.copy();
e.type = e1.type;
}
e.loc = e1.loc;
}
else
{
e = e1;
}
}
return e;
}
/* It is possible for constant folding to change an array expression of
* unknown length, into one where the length is known.
* If the expression 'arr' is a literal, set lengthVar to be its length.
*/
package void setLengthVarIfKnown(VarDeclaration lengthVar, Expression arr)
{
if (!lengthVar)
return;
if (lengthVar._init && !lengthVar._init.isVoidInitializer())
return; // we have previously calculated the length
size_t len;
if (arr.op == TOK.string_)
len = (cast(StringExp)arr).len;
else if (arr.op == TOK.arrayLiteral)
len = (cast(ArrayLiteralExp)arr).elements.dim;
else
{
Type t = arr.type.toBasetype();
if (t.ty == Tsarray)
len = cast(size_t)(cast(TypeSArray)t).dim.toInteger();
else
return; // we don't know the length yet
}
Expression dollar = new IntegerExp(Loc.initial, len, Type.tsize_t);
lengthVar._init = new ExpInitializer(Loc.initial, dollar);
lengthVar.storage_class |= STC.static_ | STC.const_;
}
/* Same as above, but determines the length from 'type'. */
package void setLengthVarIfKnown(VarDeclaration lengthVar, Type type)
{
if (!lengthVar)
return;
if (lengthVar._init && !lengthVar._init.isVoidInitializer())
return; // we have previously calculated the length
size_t len;
Type t = type.toBasetype();
if (t.ty == Tsarray)
len = cast(size_t)(cast(TypeSArray)t).dim.toInteger();
else
return; // we don't know the length yet
Expression dollar = new IntegerExp(Loc.initial, len, Type.tsize_t);
lengthVar._init = new ExpInitializer(Loc.initial, dollar);
lengthVar.storage_class |= STC.static_ | STC.const_;
}
/*********************************
* Constant fold an Expression.
* Params:
* e = expression to const fold; this may get modified in-place
* result = WANTvalue, WANTexpand, or both
* keepLvalue = `e` is an lvalue, and keep it as an lvalue since it is
* an argument to a `ref` or `out` parameter, or the operand of `&` operator
* Returns:
* Constant folded version of `e`
*/
Expression Expression_optimize(Expression e, int result, bool keepLvalue)
{
extern (C++) final class OptimizeVisitor : Visitor
{
alias visit = Visitor.visit;
Expression ret;
private const int result;
private const bool keepLvalue;
extern (D) this(Expression e, int result, bool keepLvalue)
{
this.ret = e; // default result is original expression
this.result = result;
this.keepLvalue = keepLvalue;
}
void error()
{
ret = new ErrorExp();
}
bool expOptimize(ref Expression e, int flags, bool keepLvalue = false)
{
if (!e)
return false;
Expression ex = Expression_optimize(e, flags, keepLvalue);
if (ex.op == TOK.error)
{
ret = ex; // store error result
return true;
}
else
{
e = ex; // modify original
return false;
}
}
bool unaOptimize(UnaExp e, int flags)
{
return expOptimize(e.e1, flags);
}
bool binOptimize(BinExp e, int flags)
{
expOptimize(e.e1, flags);
expOptimize(e.e2, flags);
return ret.op == TOK.error;
}
override void visit(Expression e)
{
//printf("Expression::optimize(result = x%x) %s\n", result, e.toChars());
}
override void visit(VarExp e)
{
if (keepLvalue)
{
VarDeclaration v = e.var.isVarDeclaration();
if (v && !(v.storage_class & STC.manifest))
return;
}
ret = fromConstInitializer(result, e);
}
override void visit(TupleExp e)
{
expOptimize(e.e0, WANTvalue);
for (size_t i = 0; i < e.exps.dim; i++)
{
expOptimize((*e.exps)[i], WANTvalue);
}
}
override void visit(ArrayLiteralExp e)
{
if (e.elements)
{
expOptimize(e.basis, result & WANTexpand);
for (size_t i = 0; i < e.elements.dim; i++)
{
expOptimize((*e.elements)[i], result & WANTexpand);
}
}
}
override void visit(AssocArrayLiteralExp e)
{
assert(e.keys.dim == e.values.dim);
for (size_t i = 0; i < e.keys.dim; i++)
{
expOptimize((*e.keys)[i], result & WANTexpand);
expOptimize((*e.values)[i], result & WANTexpand);
}
}
override void visit(StructLiteralExp e)
{
if (e.stageflags & stageOptimize)
return;
int old = e.stageflags;
e.stageflags |= stageOptimize;
if (e.elements)
{
for (size_t i = 0; i < e.elements.dim; i++)
{
expOptimize((*e.elements)[i], result & WANTexpand);
}
}
e.stageflags = old;
}
override void visit(UnaExp e)
{
//printf("UnaExp::optimize() %s\n", e.toChars());
if (unaOptimize(e, result))
return;
}
override void visit(NegExp e)
{
if (unaOptimize(e, result))
return;
if (e.e1.isConst() == 1)
{
ret = Neg(e.type, e.e1).copy();
}
}
override void visit(ComExp e)
{
if (unaOptimize(e, result))
return;
if (e.e1.isConst() == 1)
{
ret = Com(e.type, e.e1).copy();
}
}
override void visit(NotExp e)
{
if (unaOptimize(e, result))
return;
if (e.e1.isConst() == 1)
{
ret = Not(e.type, e.e1).copy();
}
}
override void visit(SymOffExp e)
{
assert(e.var);
}
override void visit(AddrExp e)
{
//printf("AddrExp::optimize(result = %d) %s\n", result, e.toChars());
/* Rewrite &(a,b) as (a,&b)
*/
if (e.e1.op == TOK.comma)
{
CommaExp ce = cast(CommaExp)e.e1;
auto ae = new AddrExp(e.loc, ce.e2, e.type);
ret = new CommaExp(ce.loc, ce.e1, ae);
ret.type = e.type;
return;
}
// Keep lvalue-ness
if (expOptimize(e.e1, result, true))
return;
// Convert &*ex to ex
if (e.e1.op == TOK.star)
{
Expression ex = (cast(PtrExp)e.e1).e1;
if (e.type.equals(ex.type))
ret = ex;
else if (e.type.toBasetype().equivalent(ex.type.toBasetype()))
{
ret = ex.copy();
ret.type = e.type;
}
return;
}
if (e.e1.op == TOK.variable)
{
VarExp ve = cast(VarExp)e.e1;
if (!ve.var.isOut() && !ve.var.isRef() && !ve.var.isImportedSymbol())
{
ret = new SymOffExp(e.loc, ve.var, 0, ve.hasOverloads);
ret.type = e.type;
return;
}
}
if (e.e1.op == TOK.index)
{
// Convert &array[n] to &array+n
IndexExp ae = cast(IndexExp)e.e1;
if (ae.e2.op == TOK.int64 && ae.e1.op == TOK.variable)
{
sinteger_t index = ae.e2.toInteger();
VarExp ve = cast(VarExp)ae.e1;
if (ve.type.ty == Tsarray && !ve.var.isImportedSymbol())
{
TypeSArray ts = cast(TypeSArray)ve.type;
sinteger_t dim = ts.dim.toInteger();
if (index < 0 || index >= dim)
{
e.error("array index %lld is out of bounds `[0..%lld]`", index, dim);
return error();
}
import core.checkedint : mulu;
bool overflow;
const offset = mulu(index, ts.nextOf().size(e.loc), overflow);
if (overflow)
{
e.error("array offset overflow");
return error();
}
ret = new SymOffExp(e.loc, ve.var, offset);
ret.type = e.type;
return;
}
}
}
}
override void visit(PtrExp e)
{
//printf("PtrExp::optimize(result = x%x) %s\n", result, e.toChars());
if (expOptimize(e.e1, result))
return;
// Convert *&ex to ex
// But only if there is no type punning involved
if (e.e1.op == TOK.address)
{
Expression ex = (cast(AddrExp)e.e1).e1;
if (e.type.equals(ex.type))
ret = ex;
else if (e.type.toBasetype().equivalent(ex.type.toBasetype()))
{
ret = ex.copy();
ret.type = e.type;
}
}
if (keepLvalue)
return;
// Constant fold *(&structliteral + offset)
if (e.e1.op == TOK.add)
{
Expression ex = Ptr(e.type, e.e1).copy();
if (!CTFEExp.isCantExp(ex))
{
ret = ex;
return;
}
}
if (e.e1.op == TOK.symbolOffset)
{
SymOffExp se = cast(SymOffExp)e.e1;
VarDeclaration v = se.var.isVarDeclaration();
Expression ex = expandVar(result, v);
if (ex && ex.op == TOK.structLiteral)
{
StructLiteralExp sle = cast(StructLiteralExp)ex;
ex = sle.getField(e.type, cast(uint)se.offset);
if (ex && !CTFEExp.isCantExp(ex))
{
ret = ex;
return;
}
}
}
}
override void visit(DotVarExp e)
{
//printf("DotVarExp::optimize(result = x%x) %s\n", result, e.toChars());
if (expOptimize(e.e1, result))
return;
if (keepLvalue)
return;
Expression ex = e.e1;
if (ex.op == TOK.variable)
{
VarExp ve = cast(VarExp)ex;
VarDeclaration v = ve.var.isVarDeclaration();
ex = expandVar(result, v);
}
if (ex && ex.op == TOK.structLiteral)
{
StructLiteralExp sle = cast(StructLiteralExp)ex;
VarDeclaration vf = e.var.isVarDeclaration();
if (vf && !vf.overlapped)
{
/* https://issues.dlang.org/show_bug.cgi?id=13021
* Prevent optimization if vf has overlapped fields.
*/
ex = sle.getField(e.type, vf.offset);
if (ex && !CTFEExp.isCantExp(ex))
{
ret = ex;
return;
}
}
}
}
override void visit(NewExp e)
{
expOptimize(e.thisexp, WANTvalue);
// Optimize parameters
if (e.newargs)
{
for (size_t i = 0; i < e.newargs.dim; i++)
{
expOptimize((*e.newargs)[i], WANTvalue);
}
}
if (e.arguments)
{
for (size_t i = 0; i < e.arguments.dim; i++)
{
expOptimize((*e.arguments)[i], WANTvalue);
}
}
}
override void visit(CallExp e)
{
//printf("CallExp::optimize(result = %d) %s\n", result, e.toChars());
// Optimize parameters with keeping lvalue-ness
if (expOptimize(e.e1, result))
return;
if (e.arguments)
{
Type t1 = e.e1.type.toBasetype();
if (t1.ty == Tdelegate)
t1 = t1.nextOf();
assert(t1.ty == Tfunction);
TypeFunction tf = cast(TypeFunction)t1;
for (size_t i = 0; i < e.arguments.dim; i++)
{
Parameter p = Parameter.getNth(tf.parameters, i);
bool keep = p && (p.storageClass & (STC.ref_ | STC.out_)) != 0;
expOptimize((*e.arguments)[i], WANTvalue, keep);
}
}
}
override void visit(CastExp e)
{
//printf("CastExp::optimize(result = %d) %s\n", result, e.toChars());
//printf("from %s to %s\n", e.type.toChars(), e.to.toChars());
//printf("from %s\n", e.type.toChars());
//printf("e1.type %s\n", e.e1.type.toChars());
//printf("type = %p\n", e.type);
assert(e.type);
TOK op1 = e.e1.op;
Expression e1old = e.e1;
if (expOptimize(e.e1, result))
return;
e.e1 = fromConstInitializer(result, e.e1);
if (e.e1 == e1old && e.e1.op == TOK.arrayLiteral && e.type.toBasetype().ty == Tpointer && e.e1.type.toBasetype().ty != Tsarray)
{
// Casting this will result in the same expression, and
// infinite loop because of Expression::implicitCastTo()
return; // no change
}
if ((e.e1.op == TOK.string_ || e.e1.op == TOK.arrayLiteral) &&
(e.type.ty == Tpointer || e.type.ty == Tarray))
{
const esz = e.type.nextOf().size(e.loc);
const e1sz = e.e1.type.toBasetype().nextOf().size(e.e1.loc);
if (esz == SIZE_INVALID || e1sz == SIZE_INVALID)
return error();
if (e1sz == esz)
{
// https://issues.dlang.org/show_bug.cgi?id=12937
// If target type is void array, trying to paint
// e.e1 with that type will cause infinite recursive optimization.
if (e.type.nextOf().ty == Tvoid)
return;
ret = e.e1.castTo(null, e.type);
//printf(" returning1 %s\n", ret.toChars());
return;
}
}
if (e.e1.op == TOK.structLiteral && e.e1.type.implicitConvTo(e.type) >= MATCH.constant)
{
//printf(" returning2 %s\n", e.e1.toChars());
L1:
// Returning e1 with changing its type
ret = (e1old == e.e1 ? e.e1.copy() : e.e1);
ret.type = e.type;
return;
}
/* The first test here is to prevent infinite loops
*/
if (op1 != TOK.arrayLiteral && e.e1.op == TOK.arrayLiteral)
{
ret = e.e1.castTo(null, e.to);
return;
}
if (e.e1.op == TOK.null_ && (e.type.ty == Tpointer || e.type.ty == Tclass || e.type.ty == Tarray))
{
//printf(" returning3 %s\n", e.e1.toChars());
goto L1;
}
if (e.type.ty == Tclass && e.e1.type.ty == Tclass)
{
import dmd.aggregate : Sizeok;
// See if we can remove an unnecessary cast
ClassDeclaration cdfrom = e.e1.type.isClassHandle();
ClassDeclaration cdto = e.type.isClassHandle();
if (cdto == ClassDeclaration.object && !cdfrom.isInterfaceDeclaration())
goto L1; // can always convert a class to Object
// Need to determine correct offset before optimizing away the cast.
// https://issues.dlang.org/show_bug.cgi?id=16980
cdfrom.size(e.loc);
assert(cdfrom.sizeok == Sizeok.done);
assert(cdto.sizeok == Sizeok.done || !cdto.isBaseOf(cdfrom, null));
int offset;
if (cdto.isBaseOf(cdfrom, &offset) && offset == 0)
{
//printf(" returning4 %s\n", e.e1.toChars());
goto L1;
}
}
// We can convert 'head const' to mutable
if (e.to.mutableOf().constOf().equals(e.e1.type.mutableOf().constOf()))
{
//printf(" returning5 %s\n", e.e1.toChars());
goto L1;
}
if (e.e1.isConst())
{
if (e.e1.op == TOK.symbolOffset)
{
if (e.type.toBasetype().ty != Tsarray)
{
const esz = e.type.size(e.loc);
const e1sz = e.e1.type.size(e.e1.loc);
if (esz == SIZE_INVALID ||
e1sz == SIZE_INVALID)
return error();
if (esz == e1sz)
goto L1;
}
return;
}
if (e.to.toBasetype().ty != Tvoid)
{
if (e.e1.type.equals(e.type) && e.type.equals(e.to))
ret = e.e1;
else
ret = Cast(e.loc, e.type, e.to, e.e1).copy();
}
}
//printf(" returning6 %s\n", ret.toChars());
}
override void visit(BinExp e)
{
//printf("BinExp::optimize(result = %d) %s\n", result, e.toChars());
// don't replace const variable with its initializer in e1
bool e2only = (e.op == TOK.construct || e.op == TOK.blit);
if (e2only ? expOptimize(e.e2, result) : binOptimize(e, result))
return;
if (e.op == TOK.leftShiftAssign || e.op == TOK.rightShiftAssign || e.op == TOK.unsignedRightShiftAssign)
{
if (e.e2.isConst() == 1)
{
sinteger_t i2 = e.e2.toInteger();
d_uns64 sz = e.e1.type.size(e.e1.loc);
assert(sz != SIZE_INVALID);
sz *= 8;
if (i2 < 0 || i2 >= sz)
{
e.error("shift assign by %lld is outside the range `0..%llu`", i2, cast(ulong)sz - 1);
return error();
}
}
}
}
override void visit(AddExp e)
{
//printf("AddExp::optimize(%s)\n", e.toChars());
if (binOptimize(e, result))
return;
if (e.e1.isConst() && e.e2.isConst())
{
if (e.e1.op == TOK.symbolOffset && e.e2.op == TOK.symbolOffset)
return;
ret = Add(e.loc, e.type, e.e1, e.e2).copy();
}
}
override void visit(MinExp e)
{
if (binOptimize(e, result))
return;
if (e.e1.isConst() && e.e2.isConst())
{
if (e.e2.op == TOK.symbolOffset)
return;
ret = Min(e.loc, e.type, e.e1, e.e2).copy();
}
}
override void visit(MulExp e)
{
//printf("MulExp::optimize(result = %d) %s\n", result, e.toChars());
if (binOptimize(e, result))
return;
if (e.e1.isConst() == 1 && e.e2.isConst() == 1)
{
ret = Mul(e.loc, e.type, e.e1, e.e2).copy();
}
}
override void visit(DivExp e)
{
//printf("DivExp::optimize(%s)\n", e.toChars());
if (binOptimize(e, result))
return;
if (e.e1.isConst() == 1 && e.e2.isConst() == 1)
{
ret = Div(e.loc, e.type, e.e1, e.e2).copy();
}
}
override void visit(ModExp e)
{
if (binOptimize(e, result))
return;
if (e.e1.isConst() == 1 && e.e2.isConst() == 1)
{
ret = Mod(e.loc, e.type, e.e1, e.e2).copy();
}
}
extern (D) void shift_optimize(BinExp e, UnionExp function(const ref Loc, Type, Expression, Expression) shift)
{
if (binOptimize(e, result))
return;
if (e.e2.isConst() == 1)
{
sinteger_t i2 = e.e2.toInteger();
d_uns64 sz = e.e1.type.size(e.e1.loc);
assert(sz != SIZE_INVALID);
sz *= 8;
if (i2 < 0 || i2 >= sz)
{
e.error("shift by %lld is outside the range `0..%llu`", i2, cast(ulong)sz - 1);
return error();
}
if (e.e1.isConst() == 1)
ret = (*shift)(e.loc, e.type, e.e1, e.e2).copy();
}
}
override void visit(ShlExp e)
{
//printf("ShlExp::optimize(result = %d) %s\n", result, e.toChars());
shift_optimize(e, &Shl);
}
override void visit(ShrExp e)
{
//printf("ShrExp::optimize(result = %d) %s\n", result, e.toChars());
shift_optimize(e, &Shr);
}
override void visit(UshrExp e)
{
//printf("UshrExp::optimize(result = %d) %s\n", result, toChars());
shift_optimize(e, &Ushr);
}
override void visit(AndExp e)
{
if (binOptimize(e, result))
return;
if (e.e1.isConst() == 1 && e.e2.isConst() == 1)
ret = And(e.loc, e.type, e.e1, e.e2).copy();
}
override void visit(OrExp e)
{
if (binOptimize(e, result))
return;
if (e.e1.isConst() == 1 && e.e2.isConst() == 1)
ret = Or(e.loc, e.type, e.e1, e.e2).copy();
}
override void visit(XorExp e)
{
if (binOptimize(e, result))
return;
if (e.e1.isConst() == 1 && e.e2.isConst() == 1)
ret = Xor(e.loc, e.type, e.e1, e.e2).copy();
}
override void visit(PowExp e)
{
if (binOptimize(e, result))
return;
// Replace 1 ^^ x or 1.0^^x by (x, 1)
if ((e.e1.op == TOK.int64 && e.e1.toInteger() == 1) || (e.e1.op == TOK.float64 && e.e1.toReal() == CTFloat.one))
{
ret = new CommaExp(e.loc, e.e2, e.e1);
ret.type = e.type;
return;
}
// Replace -1 ^^ x by (x&1) ? -1 : 1, where x is integral
if (e.e2.type.isintegral() && e.e1.op == TOK.int64 && cast(sinteger_t)e.e1.toInteger() == -1)
{
ret = new AndExp(e.loc, e.e2, new IntegerExp(e.loc, 1, e.e2.type));
ret.type = e.e2.type;
ret = new CondExp(e.loc, ret, new IntegerExp(e.loc, -1, e.type), new IntegerExp(e.loc, 1, e.type));
ret.type = e.type;
return;
}
// Replace x ^^ 0 or x^^0.0 by (x, 1)
if ((e.e2.op == TOK.int64 && e.e2.toInteger() == 0) || (e.e2.op == TOK.float64 && e.e2.toReal() == CTFloat.zero))
{
if (e.e1.type.isintegral())
ret = new IntegerExp(e.loc, 1, e.e1.type);
else
ret = new RealExp(e.loc, CTFloat.one, e.e1.type);
ret = new CommaExp(e.loc, e.e1, ret);
ret.type = e.type;
return;
}
// Replace x ^^ 1 or x^^1.0 by (x)
if ((e.e2.op == TOK.int64 && e.e2.toInteger() == 1) || (e.e2.op == TOK.float64 && e.e2.toReal() == CTFloat.one))
{
ret = e.e1;
return;
}
// Replace x ^^ -1.0 by (1.0 / x)
if (e.e2.op == TOK.float64 && e.e2.toReal() == CTFloat.minusone)
{
ret = new DivExp(e.loc, new RealExp(e.loc, CTFloat.one, e.e2.type), e.e1);
ret.type = e.type;
return;
}
// All other negative integral powers are illegal
if (e.e1.type.isintegral() && (e.e2.op == TOK.int64) && cast(sinteger_t)e.e2.toInteger() < 0)
{
e.error("cannot raise `%s` to a negative integer power. Did you mean `(cast(real)%s)^^%s` ?", e.e1.type.toBasetype().toChars(), e.e1.toChars(), e.e2.toChars());
return error();
}
// If e2 *could* have been an integer, make it one.
if (e.e2.op == TOK.float64)
{
version (all)
{
// Work around redundant REX.W prefix breaking Valgrind
// when built with affected versions of DMD.
// https://issues.dlang.org/show_bug.cgi?id=14952
// This can be removed once compiling with DMD 2.068 or
// older is no longer supported.
const r = e.e2.toReal();
if (r == real_t(cast(sinteger_t)r))
e.e2 = new IntegerExp(e.loc, e.e2.toInteger(), Type.tint64);
}
else
{
if (e.e2.toReal() == cast(sinteger_t)e.e2.toReal())
e.e2 = new IntegerExp(e.loc, e.e2.toInteger(), Type.tint64);
}
}
if (e.e1.isConst() == 1 && e.e2.isConst() == 1)
{
Expression ex = Pow(e.loc, e.type, e.e1, e.e2).copy();
if (!CTFEExp.isCantExp(ex))
{
ret = ex;
return;
}
}
// (2 ^^ n) ^^ p -> 1 << n * p
if (e.e1.op == TOK.int64 && e.e1.toInteger() > 0 && !((e.e1.toInteger() - 1) & e.e1.toInteger()) && e.e2.type.isintegral() && e.e2.type.isunsigned())
{
dinteger_t i = e.e1.toInteger();
dinteger_t mul = 1;
while ((i >>= 1) > 1)
mul++;
Expression shift = new MulExp(e.loc, e.e2, new IntegerExp(e.loc, mul, e.e2.type));
shift.type = e.e2.type;
shift = shift.castTo(null, Type.tshiftcnt);
ret = new ShlExp(e.loc, new IntegerExp(e.loc, 1, e.e1.type), shift);
ret.type = e.type;
return;
}
}
override void visit(CommaExp e)
{
//printf("CommaExp::optimize(result = %d) %s\n", result, e.toChars());
// Comma needs special treatment, because it may
// contain compiler-generated declarations. We can interpret them, but
// otherwise we must NOT attempt to constant-fold them.
// In particular, if the comma returns a temporary variable, it needs
// to be an lvalue (this is particularly important for struct constructors)
expOptimize(e.e1, WANTvalue);
expOptimize(e.e2, result, keepLvalue);
if (ret.op == TOK.error)
return;
if (!e.e1 || e.e1.op == TOK.int64 || e.e1.op == TOK.float64 || !hasSideEffect(e.e1))
{
ret = e.e2;
if (ret)
ret.type = e.type;
}
//printf("-CommaExp::optimize(result = %d) %s\n", result, e.e.toChars());
}
override void visit(ArrayLengthExp e)
{
//printf("ArrayLengthExp::optimize(result = %d) %s\n", result, e.toChars());
if (unaOptimize(e, WANTexpand))
return;
// CTFE interpret static immutable arrays (to get better diagnostics)
if (e.e1.op == TOK.variable)
{