From 8a285f2ed3c2126b588396f502b64273920281c9 Mon Sep 17 00:00:00 2001
From: Yuan Feng <yfeng44@ucmerced.edu>
Date: Sun, 15 Jun 2025 12:43:29 -0700
Subject: [PATCH] add support of neura.phi in interpreter

---
 test/neura/interpreter/phiOp_interpret.mlir   | 20 +++++++++++++++++++
 tools/neura-interpreter/neura-interpreter.cpp | 11 ++++++++++
 2 files changed, 31 insertions(+)
 create mode 100644 test/neura/interpreter/phiOp_interpret.mlir

diff --git a/test/neura/interpreter/phiOp_interpret.mlir b/test/neura/interpreter/phiOp_interpret.mlir
new file mode 100644
index 00000000..b6f50513
--- /dev/null
+++ b/test/neura/interpreter/phiOp_interpret.mlir
@@ -0,0 +1,20 @@
+// RUN: neura-interpreter %s | FileCheck %s
+
+module {
+  func.func @test_phi() -> f32 {
+    %true_path_val = "neura.constant"() <{
+      value = 10.0 : f32,
+      predicate = true
+    }> : () -> f32
+
+    %false_path_val = "neura.constant"() <{
+      value = 20.0 : f32,
+      predicate = false
+    }> : () -> f32
+
+    %result = "neura.phi"(%true_path_val, %false_path_val) : (f32, f32) -> f32
+
+    return %result : f32
+    // CHECK: [neura-interpreter] Output: 10.000000
+  }
+}
\ No newline at end of file
diff --git a/tools/neura-interpreter/neura-interpreter.cpp b/tools/neura-interpreter/neura-interpreter.cpp
index 53cf0eb8..383782d9 100644
--- a/tools/neura-interpreter/neura-interpreter.cpp
+++ b/tools/neura-interpreter/neura-interpreter.cpp
@@ -95,6 +95,17 @@ int main(int argc, char **argv) {
         
         valueMap[constOp.getResult()] = val;
 
+      } else if (auto phiOp = dyn_cast<neura::PhiOp>(op)) {
+        PredicatedData result{0.0f, false}; // Default to a false predicate.
+        // Find the one operand with a true predicate.
+        for (Value operand : phiOp.getOperands()) {
+            auto incoming = valueMap[operand];
+            if (incoming.predicate) {
+                result = incoming;
+                break; // Found the active value.
+            }
+        }
+        valueMap[phiOp.getResult()] = result;
       } else if (auto movOp = dyn_cast<neura::DataMovOp>(op)) {
         valueMap[movOp.getResult()] = valueMap[movOp.getOperand()];