[LLVMdev] Fix the aggressive anti-dep breaker's subregister definition handling (original) (raw)
Daniil Troshkov troshkovdanil at gmail.com
Sat Jan 24 09:17:10 PST 2015
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Oops! I'm sorry. Misprint:
KillIndices[*SubR] > KillIndices[*AI]
On Sat, Jan 24, 2015 at 8:05 PM, Daniil Troshkov <troshkovdanil at gmail.com> wrote:
Hello Hal!
r 202294 Fix the aggressive anti-dep breaker's subregister definition handling There is a problem. For example: r0.64 = {r0.32, r1.32} r2.64 = {r2.32, r3.32) def1(r0.32) def2(r1.32) def3(r0.32) use(r0.64) Try to rename def1(r0.32). According current algo we get smth like: def1(r2.32) def2(r1.32) def3(r0.32) use(r2.64) Because r0.64 was still not defined. Patch to fix it: Index: lib/CodeGen/AggressiveAntiDepBreaker.cpp =================================================================== --- lib/CodeGen/AggressiveAntiDepBreaker.cpp (revision 227005) +++ lib/CodeGen/AggressiveAntiDepBreaker.cpp (working copy) @@ -326,6 +326,7 @@ void AggressiveAntiDepBreaker::PrescanInstruction(MachineInstr *MI, unsigned Count, std::set& PassthruRegs) { + std::vector &KillIndices = State->GetKillIndices(); std::vector &DefIndices = State->GetDefIndices(); std::multimap<unsigned, AggressiveAntiDepState::RegisterReference>& RegRefs = State->GetRegRefs(); @@ -396,7 +397,7 @@ // Update def for Reg and aliases. for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI) { - // We need to be careful here not to define already-live super registers. + // We need to be careful here to define already-live super registers. // If the super register is already live, then this definition is not // a definition of the whole super register (just a partial insertion // into it). Earlier subregister definitions (which we've not yet visited @@ -403,7 +404,16 @@ // because we're iterating bottom-up) need to be linked to the same group // as this definition. if (TRI->isSuperRegister(Reg, *AI) && State->IsLive(*AI)) - continue; + for (MCSubRegIterator SubR(*AI, TRI, false); SubR.isValid(); ++SubR) + if (!TRI->isSubRegister(*SubR, Reg) && + // We get only not defined *SubR. + // If *SubR was defined then *AI is not live but it is. + // So we can use IsLive check for *SubR. + (!State->IsLive(*SubR) || _+ KillIndices[*SubR] < KillIndices[*AI])) {_ _+ KillIndices[*SubR] = KillIndices[*AI];_ _+ DefIndices[*SubR] = DefIndices[*AI];_ _+ }_ _DefIndices[*AI] = Count;_ _}_ -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150124/f569dda3/attachment.html>
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