search for: alldefsaredead

...pred:0, pred:%noreg, %CCReg<imp-def>; mem:ST4[FixedStack93] aN32_0_7:%vreg301 KILL %vreg301, <fi#93>, 0, %noreg, %CCReg<imp-def>; mem:ST4[FixedStack93] aN32_0_7:%vreg301 %a0_32<def> = COPY %vreg301; aN32_0_7:%vreg301 This results in abort: "Assertion `MI->allDefsAreDead() && "Def isn't really dead"' failed." What is the purpose of having the KILL opcode there, and do you know what might be the cause for this error? Are all the register allocators currently of high standard, or are one or more less mature, meaning things might break...

...for instance that when trying to model this straight forwardly by writing a vreg from spills and reading this from fills (not further elaborated here), that the spiller can't handle vreg def-use pairs: there are assertions making sure a spill does not have any uses , e.g. see InlineSpiller.cpp, allDefsAreDead() calls. This made me wonder if this is supported natively at all. On Wed, Dec 18, 2019 at 12:02 PM Quentin Colombet <qcolombet at apple.com> wrote: > Hi Hendrik, > > This question is a recurring one. Check for instance > https://lists.llvm.org/pipermail/llvm-dev/2016-February/0...

Hello, for an architecture that doesn't have a good way to load/store a given register class to memory, is it instead easy to spill/fill from another register class instead? e.g. - storeRegToStack/loadRegFromStack use a pseudo instruction and add virtual register operand is not supported (spill optimization doesn't seem to like this). - AMDGPU backend seems to do sth. similar? The only