llvm dev - Nov 2007 - [LLVMdev] llvm-gcc cannot emit @llvm.pow.* ?

PS: It is possible that the C front-end doesn't need to
explicitly produce BUILT_IN_POW because it is auto-synthesized
somehow from a call to "pow".  I wouldn't know.  One way to
find out is to compile a testcase and rummage around inside
the gcc trees when they hit llvm-convert.

Hi,

2007/11/22, Duncan Sands <baldrick at free.fr>:
>
> PS: It is possible that the C front-end doesn't need to
> explicitly produce BUILT_IN_POW because it is auto-synthesized
> somehow from a call to "pow".  I wouldn't know.  One way to
> find out is to compile a testcase and rummage around inside
> the gcc trees when they hit llvm-convert.

Yes, they do hit llvm-convert.  I  created  function EmitBuiltinPOW() in
llvm-convert.cpp and
add case BUILT_IN_POW to EmitBuiltinCall . Testcase result shows it will
call EmitBuiltinCall and finally emit llvm.pow.*


Sheng.
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> Yes, they do hit llvm-convert.  I  created  function EmitBuiltinPOW() in
> llvm-convert.cpp and
> add case BUILT_IN_POW to EmitBuiltinCall . Testcase result shows it will
> call EmitBuiltinCall and finally emit llvm.pow.*
Don't forget that pow(x,y) will set errno if x is negative and y is not an
integral value.  Thus it is only correct to convert to llvm.pow.* if
!flag_errno_math, like for the sqrt case.