How does builtin_sqrt get used - or not

[Andrew Hutchinson]

I am tracking test failure with avr target where function sqrtf is 
undefined reference at link time.

Here is command line:
/media/verbatim/gcchead/obj-dir/gcc/xgcc 
-B/media/verbatim/gcchead/obj-dir/gcc/ 
/media/verbatim/gcchead/trunk/gcc/testsuite/gcc.dg/pr41963.c   -O2 
-ffast-math -DSTACK_SIZE=2048 -DNO_TRAMPOLINES  -DSIGNAL_SUPPRESS 
-mmcu=atmega128  /home/andy/winavrfiles/avrtest/dejagnuboards/exit.c 
-Wl,-u,vfprintf -lprintf_flt 
-Wl,-Tbss=0x802000,--defsym=__heap_end=0x80ffff  -lm   -o pr41963.exe   

I am lead to believe that gcc might use builtin_sqrtf rather than 
sqrtf().   I am successfully using fabsf() - with no link errors.

Is their any target configuration needed for builtin_sqrtf that I should 
know about ?


Andy