In my first post (http://embdev.net/topic/166639)
I had problems with the -Wunreachable-code.

I have now removed that option, DLed latest yagarto,
and changed my prog like this:

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typedef struct {

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  int x, y;

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} POINT, *pPOINT;

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pPOINT TestProc (

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        pPOINT start,

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        pPOINT finish)

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{

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    pPOINT src, dst;

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    POINT pt;

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    src = start;

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    dst = start;

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    while (1) {

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        // read point

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        pt.x = src->x;

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        pt.y = src->y;

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        // store point & INC dst

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        dst->x = pt.x;

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        dst->y = pt.y;

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        dst++;

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        // skip same points (not just one, as before)

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        do {

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            src++;

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            if (src == finish) return dst;

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        } while ( (src->x == pt.x) && (src->y == pt.y) );

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    }

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}

and I get this:
warning: cannot optimize loop, the loop counter may overflow.

(the warning is on RETURN DST line)

Minimum command-line options to reproduce the warning are:

-Wunsafe-loop-optimizations
-Ox (-Os, -O1, -O2, -O3)

Is it really unsafe, or is it a bug?

-----------
This is a complete list of command-line options that I use,
should I add/remove some options?

-mcpu=arm926ej-s
-mfpu=fpa
-O3
-c
-MD
-MP
-gdwarf-2
-std=gnu99
-Wall
-Wextra
-pedantic
-Waggregate-return
-Wattributes
-Wcast-align
-Wcast-qual
-Wconversion
-Wdisabled-optimization
-Wdiv-by-zero
-Wfloat-equal
-Winit-self
-Winline
-Wint-to-pointer-cast
-Wlogical-op
-Wmissing-include-dirs
-Wnested-externs
-Wold-style-definition
-Wpadded
-Wpointer-arith
-Wpointer-to-int-cast
-Wpragmas
-Wredundant-decls
-Wstrict-prototypes
-Wundef
-Wunsafe-loop-optimizations
-Wunused