[llvm] [X86] Use X86FixupInstTunings to select between (V)MOVSS/D and (V)BLENDPS/D (PR #143312)

[Simon Pilgrim via llvm-commits]

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@@ -222,7 +222,30 @@ bool X86FixupInstTuningPass::processInstruction(
     return ProcessUNPCKToIntDomain(NewOpc);
   };
 
+  auto ProcessBLENDToMOV = [&](unsigned MovOpc) -> bool {
+    if (MI.getOperand(NumOperands - 1).getImm() != 1)
+      return false;
+    bool Force = MF.getFunction().hasOptSize();
+    if (!Force && !NewOpcPreferable(MovOpc))
+      return false;
+    MI.setDesc(TII->get(MovOpc));
+    MI.removeOperand(NumOperands - 1);
+    return true;
+  };
+
   switch (Opc) {
+  case X86::VBLENDPSrri: {
+    int Imm = MI.getOperand(NumOperands - 1).getImm();
+    if (Imm != 1)
+      return false;
+    return ProcessBLENDToMOV(X86::VMOVSSrr);
+  }
+  case X86::VBLENDPDrri: {
+    int Imm = MI.getOperand(NumOperands - 1).getImm();
+    if (Imm != 1)
+      return false;
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RKSimon wrote:

Drop this and just return ProcessBLENDToMOV

https://github.com/llvm/llvm-project/pull/143312