From: Nick Desaulniers

Sent: 24 January 2020 17:20

...

quoted

quoted

Good thing it's the variable being modified was not declared const; I
get spooked when I see -Wdiscarded-qualifiers because of Section
6.7.3.6 of the ISO C11 draft spec:

If an attempt is made to modify an object defined with a const-qualified
type through use of an lvalue with non-const-qualified type,
the behavior is undefined.

Well some old systems had small integer constants at fixes addresses.
So 'const int one = 1;'  would be a reference to the global constant.
An assignment like '*(int *)&one = 2;' would change the value of the
system-wide 'one' constant'.

Pretty much 'undefined'.

But no excuse for the compiler just discarding the code.

I suspect that the code to remove 'const' needs to 'launder' the value
through a suitable integer type.

	David

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