[LLVMdev] warnings in inline assembly with used labels and -Wunused-label
clattner at apple.com
Fri Jul 23 09:59:14 PDT 2010
On Jul 23, 2010, at 2:20 AM, Alexandre Colucci wrote:
> llvm-gcc 4.2 generates warnings when I compile inline assembly code that contains used labels with -Wunused-label. The generated code seems to work yet. gcc 4.2 doesn't generate those warnings. I haven't found any bugs regarding this issue in the llvm bug database.
> Does anyone know if this is a known llvm issue? Is it a warning that I can ignore and does not affect the generated code? Is there a workaround to avoid these warnings (without turning off -Wunused-label)?
What version of llvm-gcc 4.2 are you using? I think that Dale just fixed this issue, so you might try SVN head to see if it is gone now.
> Here is a small sample code that exhibits the issue:
> int main()
> sub ebx,8
> jg MyLabel
> return 0;
> Compile with llvm-gcc 4.2 on MacOSX 10.6:
> llvm-gcc-4.2 -arch i386 -Wunused-label -fasm-blocks -o inlineassembly_llvm inlineassembly.c
> inlineassembly.c: In function ‘main’:
> inlineassembly.c:7: warning: label ‘LASM$MyLabel’ defined but not used
> Compile with gcc 4.2 on MacOSX 10.6:
> gcc -arch i386 -Wunused-label -fasm-blocks -o inlineassembly inlineassembly.c
> no warnings
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