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Recognize upper bounds values '0' and '$' in slices. #7862

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Merged
dlang-bot merged 1 commit into from
Feb 10, 2018
Merged

Recognize upper bounds values '0' and '$' in slices. #7862

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11 changes: 11 additions & 0 deletions src/dmd/expressionsem.d
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Original file line number Diff line number Diff line change
Expand Up @@ -5724,10 +5724,21 @@ private extern (C++) final class ExpressionSemanticVisitor : Visitor
el = el.optimize(WANTvalue);
if (el.op == TOK.int64)
{
// Array length is known at compile-time. Upper is in bounds if it fits length.
dinteger_t length = el.toInteger();
auto bounds = IntRange(SignExtendedNumber(0), SignExtendedNumber(length));
exp.upperIsInBounds = bounds.contains(uprRange);
}
else if (exp.upr.op == TOK.int64 && exp.upr.toInteger() == 0)
{
// Upper slice expression is '0'. Value is always in bounds.
exp.upperIsInBounds = true;
}
else if (exp.upr.op == TOK.variable && (cast(VarExp)exp.upr).var.ident == Id.dollar)
{
// Upper slice expression is '$'. Value is always in bounds.
exp.upperIsInBounds = true;
}
}
else if (t1b.ty == Tpointer)
{
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10 changes: 5 additions & 5 deletions test/runnable/testbounds.d
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Expand Up @@ -200,12 +200,12 @@ void test13976()
{ auto s = da[lb .. 10]; } // 0 0 (10 <= $ && lb <= 10 )
{ auto s = da[0 .. ub%5]; } // 0 1 (ub%5 <= $ )

{ auto s = da[0 .. 0]; } // 0 1 (0 <= $ )
{ auto s = da[0 .. $]; } // 0 1 ($ <= $ )
{ auto s = da[1 .. $]; } // 0 0 ($ <= $ && 1 <= $ )
{ auto s = da[$ .. $]; } // 0 0 ($ <= $ && $ <= $ )
{ auto s = da[0 .. 0]; } // 1 1 NULL
{ auto s = da[0 .. $]; } // 1 1 NULL
{ auto s = da[1 .. $]; } // 1 0 ( 1 <= $ )
{ auto s = da[$ .. $]; } // 1 0 ( $ <= $ )
{ auto s = da[0 .. $/two]; } // 0 1 ($/2 <= $ )
{ auto s = da[$/two .. $]; } // 0 0 ($ <= $ && $/2 <= $ )
{ auto s = da[$/two .. $]; } // 1 0 ( $/2 <= $ )
{ auto s = da[$/five .. $/two]; } // 0 0 ($/2 <= $ && $/5 <= $/2)

{ auto s = sa[lb .. ub]; } // 0 0 (ub <= 10 && lb <= ub )
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