[LLVMdev] build errors while cross compiling llvm-gcc for ARM

Anton Korobeynikov anton at korobeynikov.info
Mon Jun 28 01:41:04 PDT 2010

> But I wanted to say is using these binutils I have built a llvm compiler for
> our ARM target.
That's correct. Mostly because gcc is using pre-UAL ARM assembler syntax
and LLVM switched fully to UAL one. Also, UAL is needed for correct Thumb-2
support, etc. So, in short: gcc is generating some subset of ARM assembler
and thus gas is bug-free. LLVM generates somehow different subset and this
uncovered many bugs inside gas :)

> Now our libraries which are either compiled with native ARM or with this
> llvm compiler gives same performance numbers. However this only llvm
> compiler if compared with x86 compiler gives huge performance gain.
You mean that llvm-generated code is faster on x86, but not on ARM compared
to the vendor compiler / gcc, right?

With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University

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