symfpu: Add flags

Use symfpu fork.
Add tests for symfpu properties and extra edge case checking for flags.

tests/symfpu/run-test.sh

@@ -0,0 +1,35 @@
+#!/usr/bin/env bash
+set -eu
+
+source ../gen-tests-makefile.sh
+
+ops="sqrt add sub mul div muladd"
+for op in $ops; do
+    rm -f ${op}_edges.*
+done
+
+prove_op() {
+    op=$1
+    defs=$2
+    ys_file=${op}_edges.ys
+    echo """\
+symfpu -op $op
+sat -prove-asserts -verify
+chformal -remove
+opt
+
+read_verilog -sv -formal $defs edges.sv
+chformal -lower
+prep -top edges -flatten
+sat -prove-asserts -verify
+""" > $ys_file
+}
+
+prove_op sqrt "-DSQRT"
+prove_op add "-DADD -DADDSUB -DADDS"
+prove_op sub "-DSUB -DADDSUB -DADDS"
+prove_op mul "-DMUL -DMULS"
+prove_op div "-DDIV"
+prove_op muladd "-DMULADD -DMULS -DADDS"
+
+generate_mk --yosys-scripts