[PATCH] D144670: [AArch64][GlobalISel] Legalize G_SHUFFLE_VECTOR with smaller dest size

[Jessica Paquette via Phabricator via llvm-commits]

paquette added inline comments.


================
Comment at: llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp:4993
 
-  // TODO: Normalize the shuffle vector since mask and vector length don't
-  // match.
-  if (MaskNumElts <= SrcNumElts) {
+  if (MaskNumElts == SrcNumElts) {
     return LegalizerHelper::LegalizeResult::UnableToLegalize;
----------------
Add a TODO?


================
Comment at: llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp:4999
+    // undef values.
+    SmallVector<int, 8> NewMask(Mask);
+    for (unsigned I = MaskNumElts; I < SrcNumElts; ++I) {
----------------
Why 8 vs default value for `SmallVector`?


================
Comment at: llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp:5000
+    SmallVector<int, 8> NewMask(Mask);
+    for (unsigned I = MaskNumElts; I < SrcNumElts; ++I) {
+      NewMask.push_back(-1);
----------------
don't need braces


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D144670/new/

https://reviews.llvm.org/D144670