[fpc-devel] Debugging Loop Unroll Optimization

[J. Gareth Moreton]

That looks sensible. Sorry to waste your time on this.  I'm glad it states
the for-loop variable will be left undefined - that's good enough
documentation for me.

I wouldn't call it a quick fix... more of fixing an oversight, since I can
see the trick of using Result as the for-counter being very easily
overlooked.  Of course, the perfect fix is only counting "exitn" if the
for-loop counter is Result.  One to test for later.

Gareth aka. Kit

  

 On Fri 18/05/18 14:40 , Martok listbox at martoks-place.de sent:
 > Citation: "If the loop was terminated prematurely with an exception or a

 > break statement, the loop variable retains the value it had when the 
 > loop was exited." 
 As a quick fix, not unrolling loops left with exit at least fixes this
specific 
 situation. This still leaves exceptions raised, but IIRC the handlers
don't 
 restore context anyways, we might be okay? 

 diff --git a/compiler/optloop.pas b/compiler/optloop.pas 
 index 46039ffc5a..dc714ea2cc 100644 
 --- a/compiler/optloop.pas 
 +++ b/compiler/optloop.pas 
 @@ -76,7 +76,7 @@ unit optloop; 

 function checkbreakcontinue(var n:tnode; arg: pointer): foreachnoderesult;

 begin 
 - if n.nodetype in [breakn,continuen] then 
 + if n.nodetype in [breakn,continuen,exitn] then 
 result:=fen_norecurse_true 
 else 
 result:=fen_false; 

 I'll be running this on today's snapshot, see if anything else remains. 

 -- 
 Regards, 
 Martok 

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