[llvm] [SLP] SLP's copyable elements based upon Main/Alt operations. (PR #124242)

[Alexey Bataev via llvm-commits]

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@@ -1088,6 +1144,69 @@ static InstructionsState getSameOpcode(ArrayRef<Value *> VL,
   return InstructionsState(MainOp, AltOp);
 }
 
+/// \returns analysis of the Instructions in \p VL described in
+/// InstructionsState in propose to vectorize with copyable instructions.
+static InstructionsState getCopyableOpcode(ArrayRef<Value *> VL,
+                                           const TargetLibraryInfo &TLI) {
+  if (!all_of(VL, IsaPred<Instruction>))
+    return InstructionsState::invalid();
+  Instruction *MainOp = dyn_cast<Instruction>(VL[0]);
+  Instruction *AltOp = nullptr;
+  unsigned Opcode = MainOp->getOpcode();
+  unsigned AltOpcode = Opcode;
+  if (MainOp && VectorizeCopyable && all_of(VL, IsaPred<Instruction>)) {
+    for (Value *V : VL) {
+      Instruction *I = cast<Instruction>(V);
+      if (I->isIntDivRem() || I->isFPDivRem())
+        return InstructionsState::invalid();
+      if (isa<PHINode>(I)) {
+        AltOp = nullptr;
+        break;
+      }
+      unsigned VOpcode = I->getOpcode();
+      if (VOpcode != Opcode) {
+        if (AltOpcode == Opcode) {
+          AltOpcode = VOpcode;
+          AltOp = I;
+        }
+        if (VOpcode != AltOpcode) {
+          AltOp = nullptr;
+          break;
+        }
+      }
+    }
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alexey-bataev wrote:

Better to extract into a lambda/function

https://github.com/llvm/llvm-project/pull/124242