if (!I->isPHI() && !I->isDebugValue())
InstrCount += 1;
}
- // Heuristically, don't tail-duplicate calls if it would expand code size,
- // as it's less likely to be worth the extra cost.
+ // Don't tail-duplicate calls before register allocation. Calls presents a
+ // barrier to register allocation so duplicating them may end up increasing
+ // spills.
if (InstrCount > 1 && (PreRegAlloc && HasCall))
return false;