If it was because the calls (or dereferences; or pre/post increments to the same variable) were "in the same statement", this wouldn't happen: 

C:\test>perl -e"{my$x=0; sub X{++$x;\$x}} print qq[${X()}${X()}${X()}\
+n]"
223

C:\test>perl -e"{my$x=0; sub X{++$x;\$x}} print qq[${X()} ${X()}${X()}
+\n]"
1 23

[download]
Doing so would also certainly prevent the possibility of most optimizations.

Besides that you cannot back that up with any proof, the golden rule of optimisations is that they don't break code that isn't broken without them.

Undefined ordering makes some sense in C, where the re-ordering of operations can have a significant impact upon performance.

In perl, it makes no sense at all.

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

The start of some sanity?

In reply to Re^4: Order of evaluation/interpolation of references (op order) by BrowserUk
in thread Order of evaluation/interpolation of references by Anonymous Monk

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