[PATCH] D118376: [x86] try harder to scalarize a vector load with extracted integer op uses

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added inline comments.


================
Comment at: llvm/lib/Target/X86/X86ISelLowering.cpp:43115
+    SDValue Chain = Load.getValue(1);
+    SDValue From[] = {SDValue(N, 0), SDValue(LoadVec, 1)};
+    SDValue To[] = {Load, Chain};
----------------
I think i don't quite understand what is going on here,
but i really don't understand why we'd want to
replace `SDValue(LoadVec, 1)` (which is, i guess, `LoadVec->getChain()`?)
with the new `Chain`?
We only simply replace the extract with a new load,
why could we possibly invalidate the other memory chains?

This *reeks*. (Yes, this is copied from `DAGCombiner::scalarizeExtractedVectorLoad()`)


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D118376/new/

https://reviews.llvm.org/D118376