[llvm-commits] [PATCH][MC] Add TargetAsmBackend::isFloatingPointInstruction and emit __fltused on COFF

[Michael Spencer]

The two attached patches are required for using floating point
instructions with the Microsoft C runtime.

The first adds TargetAsmBackend::isFloatingPointInstruction and adds
an X86 implementation which returns true if any x87 regs are used.
What Windows considers a floating point instruction is undocumented,
but this seems to make the ms-crt happy.

The second patch uses this function in the COFF streamer to emit an
undefined __fltused symbol if any instructions return true. This does
some linker magic with the ms-crt. If you don't do this, the runtime
aborts.

- Michael Spencer
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