[PATCH] D81013: [InstCombine] move vector select ahead of select-shuffle

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added inline comments.


================
Comment at: llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp:2416-2417
+      !is_contained(Mask, UndefMaskElem) &&
+      ShuffleVectorInst::isSelectMask(Mask)) {
+    if (X == FVal) {
+      // select Cond, (shuf_sel X, Y), X --> shuf_sel X, (select Cond, Y, X)
----------------
The problem is that we call `ShuffleVectorInst::isSelectMask()` before we ensure that select and shuffle have common operand, so by now types of their ops might be non-matching, and shuffle is lenght-changing.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D81013/new/

https://reviews.llvm.org/D81013