diff --git a/.github/workflows/benchmark_pr.yml b/.github/workflows/benchmark_pr.yml
index 2bbf2383..587fb8d4 100644
--- a/.github/workflows/benchmark_pr.yml
+++ b/.github/workflows/benchmark_pr.yml
@@ -1,9 +1,6 @@
 name: Benchmark pull request
 
-on:
-  pull_request:
-    branches:
-      - master
+on: [pull_request]
 
 permissions:
   pull-requests: write
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2356955c..125f32f3 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,8 +1,6 @@
 name: CI
 on:
   pull_request:
-    branches:
-      - master
   push:
     branches:
       - master
diff --git a/src/EGraphs/egraph.jl b/src/EGraphs/egraph.jl
index f645e44a..3166ab9d 100644
--- a/src/EGraphs/egraph.jl
+++ b/src/EGraphs/egraph.jl
@@ -223,38 +223,20 @@ Returns the canonical e-class id for a given e-class.
 
 @inline Base.getindex(g::EGraph, i::Id) = g.classes[IdKey(find(g, i))]
 
-# function canonicalize(g::EGraph, n::VecExpr)::VecExpr
-#   if !v_isexpr(n)
-#     v_hash!(n)
-#     return n
-#   end
-#   l = v_arity(n)
-#   new_n = v_new(l)
-#   v_set_flag!(new_n, v_flags(n))
-#   v_set_head!(new_n, v_head(n))
-#   for i in v_children_range(n)
-#     @inbounds new_n[i] = find(g, n[i])
-#   end
-#   v_hash!(new_n)
-#   new_n
-# end
-
 function canonicalize!(g::EGraph, n::VecExpr)
-  v_isexpr(n) || @goto ret
-  for i in (VECEXPR_META_LENGTH + 1):length(n)
-    @inbounds n[i] = find(g, n[i])
+  if v_isexpr(n)
+    for i in (VECEXPR_META_LENGTH + 1):length(n)
+      @inbounds n[i] = find(g, n[i])
+    end
   end
-  v_unset_hash!(n)
-  @label ret
-  v_hash!(n)
   n
 end
 
 function lookup(g::EGraph, n::VecExpr)::Id
   canonicalize!(g, n)
-  h = IdKey(v_hash(n))
 
-  haskey(g.memo, n) ? find(g, g.memo[n]) : 0
+  id = get(g.memo, n, zero(Id))
+  iszero(id) ? id : find(g, id)
 end
 
 
@@ -272,9 +254,10 @@ Inserts an e-node in an [`EGraph`](@ref)
 """
 function add!(g::EGraph{ExpressionType,Analysis}, n::VecExpr, should_copy::Bool)::Id where {ExpressionType,Analysis}
   canonicalize!(g, n)
-
-  haskey(g.memo, n) && return g.memo[n]
-
+  
+  id = get(g.memo, n, zero(Id))
+  iszero(id) || return id
+  
   if should_copy
     n = copy(n)
   end
@@ -319,28 +302,21 @@ function addexpr!(g::EGraph, se)::Id
   se isa EClass && return se.id
   e = preprocess(se)
 
-  n = if isexpr(e)
-    args = iscall(e) ? arguments(e) : children(e)
-    ar = length(args)
-    n = v_new(ar)
-    v_set_flag!(n, VECEXPR_FLAG_ISTREE)
-    iscall(e) && v_set_flag!(n, VECEXPR_FLAG_ISCALL)
-
-    h = iscall(e) ? operation(e) : head(e)
-    v_set_head!(n, add_constant!(g, h))
-
-    # get the signature from op and arity 
-    v_set_signature!(n, hash(maybe_quote_operation(h), hash(ar)))
-
-    for i in v_children_range(n)
-      @inbounds n[i] = addexpr!(g, args[i - VECEXPR_META_LENGTH])
-    end
-    n
-  else # constant enode
-    VecExpr(Id[Id(0), Id(0), Id(0), add_constant!(g, e)])
+  isexpr(e) || return add!(g, VecExpr(Id[Id(0), Id(0), add_constant!(g, e)]), false) # constant enode
+
+  args = iscall(e) ? arguments(e) : children(e)
+  ar = length(args)
+  n = v_new(ar)
+  v_set_flag!(n, VECEXPR_FLAG_ISTREE)
+  iscall(e) && v_set_flag!(n, VECEXPR_FLAG_ISCALL)
+  h = iscall(e) ? operation(e) : head(e)
+  v_set_head!(n, add_constant!(g, h))
+  # get the signature from op and arity 
+  v_set_signature!(n, hash(maybe_quote_operation(h), hash(ar)))
+  for i in v_children_range(n)
+    @inbounds n[i] = addexpr!(g, args[i - VECEXPR_META_LENGTH])
   end
-  id = add!(g, n, false)
-  return id
+  add!(g, n, false)
 end
 
 """
@@ -431,9 +407,8 @@ function process_unions!(g::EGraph{ExpressionType,AnalysisType})::Int where {Exp
     while !isempty(g.pending)
       (node::VecExpr, eclass_id::Id) = pop!(g.pending)
       canonicalize!(g, node)
-      if haskey(g.memo, node)
-        old_class_id = g.memo[node]
-        g.memo[node] = eclass_id
+      old_class_id = get!(g.memo, node, eclass_id)
+      if old_class_id != eclass_id
         did_something = union!(g, old_class_id, eclass_id)
         # TODO unique! can node dedup be moved here? compare performance
         # did_something && unique!(g[eclass_id].nodes)
@@ -473,9 +448,8 @@ function check_memo(g::EGraph)::Bool
   for (id, class) in g.classes
     @assert id.val == class.id
     for node in class.nodes
-      if haskey(test_memo, node)
-        old_id = test_memo[node]
-        test_memo[node] = id.val
+      old_id = get!(test_memo, node, id.val)
+      if old_id != id.val
         @assert find(g, old_id) == find(g, id.val) "Unexpected equivalence $node $(g[find(g, id.val)].nodes) $(g[find(g, old_id)].nodes)"
       end
     end
@@ -483,7 +457,7 @@ function check_memo(g::EGraph)::Bool
 
   for (node, id) in test_memo
     @assert id == find(g, id)
-    @assert id == find(g, g.memo[node])
+    @assert id == find(g, g.memo[node]) "Entry for $node at $id in test_memo was incorrect."
   end
 
   true
diff --git a/src/Patterns.jl b/src/Patterns.jl
index cf0a9ee4..2568f176 100644
--- a/src/Patterns.jl
+++ b/src/Patterns.jl
@@ -26,7 +26,7 @@ isground(p::AbstractPat) = false
 struct PatLiteral <: AbstractPat
   value
   n::VecExpr
-  PatLiteral(val) = new(val, VecExpr(Id[0, 0, 0, hash(val)]))
+  PatLiteral(val) = new(val, VecExpr(Id[0, 0, hash(val)]))
 end
 
 PatLiteral(p::AbstractPat) = throw(DomainError(p, "Cannot construct a pattern literal of another pattern object."))
diff --git a/src/vecexpr.jl b/src/vecexpr.jl
index 1e8a83ba..53183bcf 100644
--- a/src/vecexpr.jl
+++ b/src/vecexpr.jl
@@ -34,14 +34,12 @@ const Id = UInt64
     end
 
 An e-node is represented by `Vector{Id}` where:
-* Position 1 stores the hash of the `VecExpr`.
-* Position 2 stores the bit flags (`isexpr` or `iscall`).
-* Position 3 stores the signature
-* Position 4 stores the hash of the `head` (if `isexpr`) or node value in the e-graph constants.
+* Position 1 stores the bit flags (`isexpr` or `iscall`).
+* Position 2 stores the signature
+* Position 3 stores the hash of the `head` (if `isexpr`) or node value in the e-graph constants.
 * The rest of the positions store the e-class ids of the children nodes.
 
 The expression is represented as an array of integers to improve performance.
-The hash value for the VecExpr is cached in the first position for faster lookup performance in dictionaries.
 """
 struct VecExpr
   data::Vector{Id}
@@ -49,12 +47,12 @@ end
 
 const VECEXPR_FLAG_ISTREE = 0x01
 const VECEXPR_FLAG_ISCALL = 0x10
-const VECEXPR_META_LENGTH = 4
+const VECEXPR_META_LENGTH = 3
 
-@inline v_flags(n::VecExpr)::Id = @inbounds n.data[2]
-@inline v_unset_flags!(n::VecExpr) = @inbounds (n.data[2] = 0)
+@inline v_flags(n::VecExpr)::Id = @inbounds n.data[1]
+@inline v_unset_flags!(n::VecExpr) = @inbounds (n.data[1] = 0)
 @inline v_check_flags(n::VecExpr, flag::Id)::Bool = !iszero(v_flags(n) & flags)
-@inline v_set_flag!(n::VecExpr, flag)::Id = @inbounds (n.data[2] = n.data[2] | flag)
+@inline v_set_flag!(n::VecExpr, flag)::Id = @inbounds (n.data[1] = n.data[1] | flag)
 
 """Returns `true` if the e-node ID points to a an expression tree."""
 @inline v_isexpr(n::VecExpr)::Bool = !iszero(v_flags(n) & VECEXPR_FLAG_ISTREE)
@@ -65,33 +63,15 @@ const VECEXPR_META_LENGTH = 4
 """Number of children in the e-node."""
 @inline v_arity(n::VecExpr)::Int = length(n.data) - VECEXPR_META_LENGTH
 
-"""
-Compute the hash of a `VecExpr` and store it as the first element.
-"""
-@inline function v_hash!(n::VecExpr)::Id
-  if iszero(n.data[1])
-    n.data[1] = hash(@view n.data[2:end])
-  else
-    # h = hash(@view n[2:end])
-    # @assert h == n[1]
-    n.data[1]
-  end
-end
-
-"""The hash of the e-node."""
-@inline v_hash(n::VecExpr)::Id = @inbounds n.data[1]
-Base.hash(n::VecExpr) = v_hash(n) # IdKey not necessary here
-Base.:(==)(a::VecExpr, b::VecExpr) = (@view a.data[2:end]) == (@view b.data[2:end])
-
-"""Set e-node hash to zero."""
-@inline v_unset_hash!(n::VecExpr)::Id = @inbounds (n.data[1] = Id(0))
+Base.hash(n::VecExpr) = hash(n.data)
+Base.:(==)(a::VecExpr, b::VecExpr) = a.data == b.data
 
 """E-class IDs of the children of the e-node."""
 @inline v_children(n::VecExpr) = @view n.data[(VECEXPR_META_LENGTH + 1):end]
 
-@inline v_signature(n::VecExpr)::Id = @inbounds n.data[3]
+@inline v_signature(n::VecExpr)::Id = @inbounds n.data[2]
 
-@inline v_set_signature!(n::VecExpr, sig::Id) = @inbounds (n.data[3] = sig)
+@inline v_set_signature!(n::VecExpr, sig::Id) = @inbounds (n.data[2] = sig)
 
 "The constant ID of the operation of the e-node, or the e-node ."
 @inline v_head(n::VecExpr)::Id = @inbounds n.data[VECEXPR_META_LENGTH]
@@ -102,7 +82,6 @@ Base.:(==)(a::VecExpr, b::VecExpr) = (@view a.data[2:end]) == (@view b.data[2:en
 """Construct a new, empty `VecExpr` with `len` children."""
 @inline function v_new(len::Int)::VecExpr
   n = VecExpr(Vector{Id}(undef, len + VECEXPR_META_LENGTH))
-  v_unset_hash!(n)
   v_unset_flags!(n)
   n
 end