RESOLVED DUPLICATE of bug 151246 151146
Air::spillEverything and Air::iteratedRegisterCoalescing don't take into account Inst::extraClobberedRegs() 
https://bugs.webkit.org/show_bug.cgi?id=151146
Summary Air::spillEverything and Air::iteratedRegisterCoalescing don't take into acco...
Filip Pizlo
Reported 2015-11-11 11:48:08 PST
Both allocators have a loop devoted to ensuring that all Def's interfere with each other. Inst::extraClobberedRegs() is like an extra set of Def's. This is important because it's what ensures that we don't put something into a register that is clobbered by a call.
Attachments
Add attachment proposed patch, testcase, etc.
Filip Pizlo
Comment 1 2015-11-11 11:58:09 PST
I think that both allocators want an abstraction like: inst.forEachTmpIncludingExtra( [&] (Tmp tmp, Arg::Role role, Arg::Type type) { // tmp is not a reference, since we cannot edit an extraClobberedReg. }); This could be implemented as: template<typename Functor> void forEachTmpIncludingExtra(const Functor& functor) { forEachTmp( [&] (Tmp& tmp, Arg::Role role, Arg::Type type) { functor(tmp, role, type); }); if (hasSpecial()) { extraClobberedRegs().forEach( [&] (Reg reg) { functor(Tmp(reg), Arg::Def, reg.isGPR() ? Arg::GP : Arg::FP); }); } } Armed with such an abstraction, we could fix the bug by just changing which method the register allocators call when handling Def-to-Def interference.
Benjamin Poulain
Comment 2 2015-11-16 16:49:23 PST
Fixed in https://bugs.webkit.org/show_bug.cgi?id=151246 *** This bug has been marked as a duplicate of bug 151246 ***
Note You need to log in before you can comment on or make changes to this bug.