[llvm-dev] Reserved/Unallocatable Registers

Matt Arsenault via llvm-dev llvm-dev at lists.llvm.org
Fri Feb 26 11:41:47 PST 2016

On 02/25/2016 06:14 PM, Matthias Braun via llvm-dev wrote:
> 1) The value read from a reserved register cannot be predicted. Reading a reserved register twice may each time produce a different result.
This seems broken to me that treating another copy should be assumed to 
produce a different result. This seems like it should be optimized, and 
have a special volatile_copy instruction for the special cases where the 
reserved register may randomly change.


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