[llvm-dev] x86 instructions EFLAGS in TableGen
Antonin Reitz via llvm-dev
llvm-dev at lists.llvm.org
Mon Jun 24 19:58:49 PDT 2019
Hello,
Here is one question regarding the LLVM TableGen:
Which file in the llvm/lib/Target/X86 folder describes how the bits in
the EFLAGS register are modified by the x86 instructions? For example,
in the "X86InstrInfo.td" file, lines 2134-2135, it says:
let SchedRW = [WriteALU], Defs = [EFLAGS], Uses = [EFLAGS] in {
def CLC : I<0xF8, RawFrm, (outs), (ins), "clc", []>;
So it says the Defs of CLC is EFLAGS, but actually the CLC instruction
only clears the "CF" flag in the EFLAGS register and has nothing to do
with the other bits of EFLAGS. So which files in this folder describes
the fact that CLC only modifies the CF bit?
Thank you in advance,
Antonin Reitz
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