[clang] [llvm] [CodeGen] Fix inline asm clobber-list registers incorrectly marked Ea… (PR #206222)

[Jessica Clarke via cfe-commits]

https://github.com/jrtc27 requested changes to this pull request.

Is this actually true? GCC's docs say:

> When the compiler selects which registers to use to represent input and output operands, it does not use any of the clobbered registers. As a result, clobbered registers are available for any use in the assembler code.

-- https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Clobbers-and-Scratch-Registers

And I don't see how this change can be right, given that would prevent any inline asm that clobbers a fixed register before it has fully consumed its inputs.

https://github.com/llvm/llvm-project/pull/206222