Re: [Committed] PR28473: wrong code folding (unsigned long long)round()

[Uros Bizjak <ubizjak at gmail dot com>]

Hello Roger!

> The following patch has been tested on i686-pc-linux-gnu with a
> full "make bootstrap", all default languages including Ada, and
> regression tested with a top-level "make -k check" with no new
> failures.
>
> Committed to mainline as revision 115742.  I'll backport this to
> the release branches after a few days without problems.  My apologies
> and gratitude again to Richard; I didn't realise he was investigating
> a solution when Andrew Pinski asked that I look into this PR.
>
>  
>
> 2006-07-25  Roger Sayle  <roger@eyesopen.com>
>
> 	PR middle-end/28473
> 	* convert.c (convert_to_integer): When transforming (T)foo(x) into
> 	bar(x) check that bar's result type can represent all the values of T.
>
> 	* gcc.dg/fold-convround-1.c: New test case.
>  
Your patch introduces a regression on x86_64:

Running target unix
FAIL: gcc.dg/torture/builtin-convert-2.c  -O1  (test for excess errors)
FAIL: gcc.dg/torture/builtin-convert-2.c  -O2  (test for excess errors)
FAIL: gcc.dg/torture/builtin-convert-2.c  -O3 -fomit-frame-pointer  
(test for excess errors)
FAIL: gcc.dg/torture/builtin-convert-2.c  -O3 -g  (test for excess errors)
FAIL: gcc.dg/torture/builtin-convert-2.c  -Os  (test for excess errors)

The errors are:

/tmp/ccbJSyuK.o(.text+0x39): In function `foo':
builtin-convert-2.c: undefined reference to `lround'
/tmp/ccbJSyuK.o(.text+0x49):builtin-convert-2.c: undefined reference to 
`llround'
/tmp/ccbJSyuK.o(.text+0x58):builtin-convert-2.c: undefined reference to 
`link_error_round_llround'
/tmp/ccbJSyuK.o(.text+0x63):builtin-convert-2.c: undefined reference to 
`lroundf'
/tmp/ccbJSyuK.o(.text+0x71):builtin-convert-2.c: undefined reference to 
`llroundf'
...etc...

It looks that the conversion is now effectively disabled on 64bit targets...

Uros.