reduce codegen on YaoBlocks.mat methods (EnzymeAD#343)

Author: mofeing

ext/ReactantYaoBlocksExt.jl

@@ -7,30 +7,35 @@ function YaoBlocks.mat(
     ::Type{T}, R::RotationGate{D,Reactant.TracedRNumber{S},<:XGate}
 ) where {D,T,S}
     M = Reactant.broadcast_to_size(zero(T), (2, 2))
-    M[1, 1] = cos(R.theta / 2)
-    M[2, 2] = cos(R.theta / 2)
-    M[1, 2] = -im * sin(R.theta / 2)
-    M[2, 1] = -im * sin(R.theta / 2)
+    c = cos(R.theta / 2)
+    s = -im * sin(R.theta / 2)
+    M[1, 1] = c
+    M[2, 2] = c
+    M[1, 2] = s
+    M[2, 1] = s
     return M
 end
 
 function YaoBlocks.mat(
     ::Type{T}, R::RotationGate{D,Reactant.TracedRNumber{S},<:YGate}
 ) where {D,T,S}
     M = Reactant.broadcast_to_size(zero(T), (2, 2))
-    M[1, 1] = cos(R.theta / 2)
-    M[2, 2] = cos(R.theta / 2)
-    M[1, 2] = -sin(R.theta / 2)
-    M[2, 1] = sin(R.theta / 2)
+    c = cos(R.theta / 2)
+    s = sin(R.theta / 2)
+    M[1, 1] = c
+    M[2, 2] = c
+    M[1, 2] = -s
+    M[2, 1] = s
     return M
 end
 
 function YaoBlocks.mat(
     ::Type{T}, R::RotationGate{D,Reactant.TracedRNumber{S},<:ZGate}
 ) where {D,T,S}
     M = Reactant.broadcast_to_size(zero(T), (2, 2))
-    M[1, 1] = exp(-im * R.theta / 2)
-    M[2, 2] = exp(im * R.theta / 2)
+    x = exp(im * R.theta / 2)
+    M[1, 1] = conj(x)
+    M[2, 2] = x
     return M
 end