// Compiler options: -optimize using System; class Test { public static int Main () { //switching to a constant fixes the problem double thisIsCausingTheProblem = 5.0; double[,] m1 = new double[4, 4] { { 1.0, 0.0, 0.0, thisIsCausingTheProblem }, { 0.0, 1.0, 0.0, thisIsCausingTheProblem }, { 0.0, 0.0, 1.0, thisIsCausingTheProblem }, { 0.0, 0.0, 0.0, 1.0 } }; var r = m1[0, 3]; if (r != 5) return 1; return 0; } }