search for: outval_virtreg

...(cpsr in ARM). Flag in the SelectionDAG stuff is so named because it was originally used for condition codes. However, it has since grown to mean "keep these two nodes always together". In the case of return, you want the scheduler to produce code like this (on PPC): ... R3 = outval_virtreg blr not like this: ... R3 = outval_virtreg ... blr So the copy and blr are flagged together. Another case where flags are useful are for things like the X86 variable shift instruction. There the shift amount is required to be in the CL register, so we generate code like this:...

I have changed the way in which the ARM backend generates a function return. Instead of expanding a RET to a CopyToReg;RETFLAG, it now expands into a CopyToReg;BRIND. I haven't commit it yet, but the patch is attached. In my opinion the resulting code is easier to understand, but I have some questions: Why all backends use RETFLAG? Why it is named RETFLAG? Why the Copy that places the

...named because it was originally used > for condition codes. However, it has since grown to mean "keep these two > nodes always together". In the case of return, you want the scheduler to > produce code like this (on PPC): That clarifies a lot! Thanks. > ... > R3 = outval_virtreg > blr > > not like this: > > ... > R3 = outval_virtreg > ... > blr > > So the copy and blr are flagged together. > > Another case where flags are useful are for things like the X86 variable > shift instruction. There the shift amount is require...