arphaman added inline comments.
================
Comment at: lib/CodeGen/CGExpr.cpp:1323
+ if (result.HasSideEffects && !AllowSideEffects) {
+ assert(!isa<DeclRefExpr>(E) && "declrefs should not have side effects");
return ConstantEmission();
----------------
rjmccall wrote:
> The side effects here are those associated with the initializer of the
> referenced declaration, not the DRE itself. Some expressions can be
> constant-evaluated despite having side-effects because the side-effects occur
> in an ignored operand, like the LHS of a comma or the base of a MemberExpr
> that refers to a static member.
>
> We can't allow side effects here because (1) we're not actually collecting
> the side-effectful expressions to emit and (2) we'd need some permission from
> the context to decide that we're allowed to do so anyway (with a lambda
> capture, those side-effects have actually already been emitted, but I'm not
> convinced that's always true).
>
> On the other hand, I think we need to be able to emit MemberExprs to static
> members as constants despite the presence of side-effects in their base
> expressions, and I can't think of any reasonable way to do that except
> actually making a temporary DeclRefExpr to try to constant-emit instead.
Thanks, I think I understand your explanation.
I will try using temporary a DRE instead when a static variable is used in a
member expression. That means that the old integer field evaluation code will
have to stay though.
Repository:
rL LLVM
https://reviews.llvm.org/D36876
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