[llvm] [SandboxVec][LoadStoreVec] Add support for constants (PR #189769)

[via llvm-commits]

================
@@ -97,44 +97,74 @@ bool LoadStoreVec::runOnRegion(Region &Rgn, const Analyses &A) {
   // TODO: For now we only support load operands.
   // TODO: For now we don't cross BBs.
   // TODO: For now don't vectorize if the loads have external uses.
-  if (!all_of(Operands, [BB](Value *V) {
-        auto *LI = dyn_cast<LoadInst>(V);
-        if (LI == nullptr)
-          return false;
-        if (LI->getParent() != BB)
-          return false;
-        if (LI->hasNUsesOrMore(2))
-          return false;
-        return true;
-      }))
-    return false;
-  // TODO: Try to avoid the extra copy to an instruction vector.
-  SmallVector<Instruction *, 8> Loads;
-  Loads.reserve(Operands.size());
-  for (Value *Op : Operands)
-    Loads.push_back(cast<Instruction>(Op));
-
-  bool Consecutive = VecUtils::areConsecutive<LoadInst, Instruction>(
-      Loads, A.getScalarEvolution(), *DL);
-  if (!Consecutive)
-    return false;
-  if (!canVectorize(Loads, Sched))
+  bool AllLoads = all_of(Operands, [BB](Value *V) {
+    auto *LI = dyn_cast<LoadInst>(V);
+    if (LI == nullptr)
+      return false;
+    // TODO: For now we don't cross BBs.
+    if (LI->getParent() != BB)
+      return false;
+    if (LI->hasNUsesOrMore(2))
+      return false;
+    return true;
+  });
+  bool AllConstants =
+      all_of(Operands, [](Value *V) { return isa<Constant>(V); });
+  if (!AllLoads && !AllConstants)
     return false;
 
-  // Generate vector store and vector load
-  Type *Ty = VecUtils::getCombinedVectorTypeFor(Bndl, *DL);
-  Value *LdPtr = cast<LoadInst>(Loads[0])->getPointerOperand();
-  // TODO: Compute alignment.
-  Align LdAlign(1);
-  auto LdWhereIt = std::next(VecUtils::getLowest(Loads)->getIterator());
-  auto *VecLd =
-      LoadInst::create(Ty, LdPtr, LdAlign, LdWhereIt, Ctx, "VecIinitL");
+  Value *VecOp = nullptr;
+  SmallVector<Instruction *, 8> Loads;
----------------
vporpo wrote:

It is declared outside the `if` because we are using it in `tryEraseDeadInstrs(Stores, Loads)` after we emit the stores. But I think we can pass `Operands` as the second argument of `tryEraseDeadInstrs(Stores, Operands)`.

https://github.com/llvm/llvm-project/pull/189769