[llvm-dev] XOR A, A treatment

[James Courtier-Dutton via llvm-dev]

Hi,

I am wondering about what suitable assembler level instruction substations
are.
For example:
Result = XOR Reg1, Reg1;

Result is always zero, with the flags cleared.
Could I substitute this for:
Result = XOR Constant0, Constant0;

Thus freeing up Reg1 usage.
I think this would be a valid substitution, but I wanted to check with the
knowledgeable people on this list as to whether I am missing something
important.

Other possible substitutions might be:
Result = XOR Reg2, Reg2;
Because it does not actually matter which reg is used.

Kind Regards

James
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