From b5b937e2f28ee2d5e7f055f880c5524375cb5b67 Mon Sep 17 00:00:00 2001
From: Geza Lore <gezalore@gmail.com>
Date: Wed, 1 May 2024 16:22:56 +0100
Subject: [PATCH] Fix missed optimization in V3Delayed (#5089)

Checking the wrong node meant we never actually pushed constant
bit-select indices into the delayed update, as was the intention, but
always generated a temporary instead.
---
 src/V3Delayed.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/V3Delayed.cpp b/src/V3Delayed.cpp
index cb31f131e..ce198f953 100644
--- a/src/V3Delayed.cpp
+++ b/src/V3Delayed.cpp
@@ -277,7 +277,7 @@ class DelayedVisitor final : public VNVisitor {
         AstNodeExpr* bitreadp = nullptr;  // Code to read Vdlyvlsb
         if (bitselp) {
             AstNodeExpr* const lsbvaluep = bitselp->lsbp()->unlinkFrBack();
-            if (VN_IS(bitselp->fromp(), Const)) {
+            if (VN_IS(lsbvaluep, Const)) {
                 // vlsb = constant, can just push constant into where we use it
                 bitreadp = lsbvaluep;
             } else {