Merge pull request #302 from 2b3o4o/dead-branch

add dead-branch benchmark

benchmarks/long/dead-branch.bril

@@ -0,0 +1,32 @@
+@main {
+  v1: int = const 1;
+  v2: int = const 0;
+  counter: int = const 0;
+
+.loop_start:
+  v7: int = id counter;
+  v8: int = const 99;
+  v9: bool = lt v7 v8;
+  br v9 .loop_body .loop_end;
+
+.loop_body:
+  v3: bool = eq v1 v2;  # Always false
+  br v3 .then .else;  # .then is a dead branch - this br instruction can be optimized out by a smart compiler
+
+.then:
+  v4: int = const 100;
+  print v4;
+
+.else:
+  v4: int = const 50;
+
+  v10: int = id counter;
+  v11: int = const 1;
+  v12: int = add v10 v11;
+  counter: int = id v12;
+
+  jmp .loop_start;
+
+.loop_end:
+  print v4;
+}

benchmarks/long/dead-branch.out

@@ -0,0 +1 @@
+50

benchmarks/long/dead-branch.prof

@@ -0,0 +1 @@
+total_dyn_inst: 1196

docs/tools/bench.md

@@ -24,6 +24,7 @@ The current benchmarks are:
 * `cordic`: Print an approximation of sine(radians) using 8 iterations of the [CORDIC algorithm](https://en.wikipedia.org/wiki/CORDIC).
 * `csrmv`: Multiply a sparse matrix in the [Compressed Sparse Row (CSR)][csr] format with a dense vector. The matrix and input vector are generated using a [Linear Feedback Shift Register](https://en.wikipedia.org/wiki/Linear-feedback_shift_register) random number generator.
 * `digial-root`: Computes the digital root of the input number.
+* `dead-branch`: Repeatedly call a br instruction whose condition always evaluates to false. The dead branch should be pruned by a smart compiler.
 * `dot-product`: Computes the dot product of two vectors.
 * `eight-queens`: Counts the number of solutions for *n* queens problem, a generalization of [Eight queens puzzle][eight_queens].
 * `euclid`: Calculates the greatest common divisor between two large numbers using the [Euclidean Algorithm][euclid] with a helper function for the modulo operator.