llvm-project

4a2fa084 - [VPlan] Support VPWidenIntOrFpInductionRecipes with EVL tail folding (#144666)

[VPlan] Support VPWidenIntOrFpInductionRecipes with EVL tail folding (#144666) Following on from #118638, this handles widened induction variables with EVL tail folding by setting the VF operand to be EVL, calculated in the vector body. We need to do this for correctness since with EVL tail folding the number of elements processed in the penultimate iteration may not be VF, but the runtime EVL, and we need take this into account when updating the backedge value. - Because the VF may now not be a live-in we need to move the insertion point to just after the VFs definition - We also need to avoid truncating it when it's the same size as the step type, previously this wasn't a problem for live-ins. - Also because the VF may be smaller than the IV type, since the EVL is always i32, we may need to zext it. On -march=rva23u64 -O3 we get 87.1% more loops vectorized on TSVC, and 42.8% more loops vectorized on SPEC CPU 2017