[PATCH] D117863: [ISEL] Move trivial step_vector folds to FoldConstantArithmetic.

[Sander de Smalen via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG699e22a083f2: [ISEL] Move trivial step_vector folds to FoldConstantArithmetic. (authored by sdesmalen).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D117863/new/

https://reviews.llvm.org/D117863

Files:
  llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp


Index: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -5418,6 +5418,19 @@
     }
   }
 
+  // Fold (mul step_vector(C0), C1) to (step_vector(C0 * C1)).
+  //      (shl step_vector(C0), C1) -> (step_vector(C0 << C1))
+  if ((Opcode == ISD::MUL || Opcode == ISD::SHL) &&
+      Ops[0].getOpcode() == ISD::STEP_VECTOR) {
+    APInt RHSVal;
+    if (ISD::isConstantSplatVector(Ops[1].getNode(), RHSVal)) {
+      APInt NewStep = Opcode == ISD::MUL
+                          ? Ops[0].getConstantOperandAPInt(0) * RHSVal
+                          : Ops[0].getConstantOperandAPInt(0) << RHSVal;
+      return getStepVector(DL, VT, NewStep);
+    }
+  }
+
   auto IsScalarOrSameVectorSize = [NumElts](const SDValue &Op) {
     return !Op.getValueType().isVector() ||
            Op.getValueType().getVectorElementCount() == NumElts;


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