Convert the DFG tests to use filecheck.

tests/cfg/loop.cton

@@ -1,12 +1,13 @@
 ; For testing cfg generation. This code is nonsense.
 
 function nonsense(i32, i32) -> f32 {
+; check: digraph nonsense {
 
 ebb0(v1: i32, v2: i32):
     v3 = f64const 0x0.0
-    brz v2, ebb2            ;;;; ebb0:inst1 -> ebb2
+    brz v2, ebb2            ; unordered: ebb0:inst1 -> ebb2
     v4 = iconst.i32 0
-    jump ebb1(v4)           ;;;; ebb0:inst3 -> ebb1
+    jump ebb1(v4)           ; unordered: ebb0:inst3 -> ebb1
 
 ebb1(v5: i32):
     v6 = imul_imm v5, 4
@@ -17,7 +18,7 @@ ebb1(v5: i32):
     v11 = fadd v9, v10
     v12 = iadd_imm v5, 1
     v13 = icmp ult, v12, v2
-    brnz v13, ebb1(v12)     ;;;; ebb1:inst12 -> ebb1
+    brnz v13, ebb1(v12)     ; unordered: ebb1:inst12 -> ebb1
     v14 = f64const 0.0
     v15 = f64const 0.0
     v16 = fdiv v14, v15

tests/cfg/run.sh

@@ -16,9 +16,7 @@ fi
 declare -a fails
 
 for testcase in $(find cfg -name '*.cton'); do
-    annotations=$(cat $testcase | awk /';;;;'/ | awk -F ";;;;" '{print $2}' | sort)
-    connections=$("${CTONUTIL}" print-cfg "$testcase" | awk /"->"/ | sort)
-    if diff -u <(echo $annotations) <(echo $connections); then
+    if "${CTONUTIL}" print-cfg "$testcase" | "${CTONUTIL}" filecheck "$testcase"; then
         echo OK $testcase
     else
         fails=(${fails[@]} "$testcase")

tests/cfg/traps_early.cton

@@ -2,16 +2,17 @@
 ; a terminating instruction before any connections have been made.
 
 function nonsense(i32) {
+; check: digraph nonsense {
 
 ebb0(v1: i32):
     trap
-    brnz v1, ebb2   ;;;; ebb0:inst1 -> ebb2
-    jump ebb1       ;;;; ebb0:inst2 -> ebb1
+    brnz v1, ebb2   ; unordered: ebb0:inst1 -> ebb2
+    jump ebb1       ; unordered: ebb0:inst2 -> ebb1
 
 ebb1:
     v2 = iconst.i32 0
     v3 = iadd v1, v3
-    jump ebb0(v3)   ;;;; ebb1:inst5 -> ebb0
+    jump ebb0(v3)   ; unordered: ebb1:inst5 -> ebb0
 
 ebb2:
     return v1

tests/cfg/unused_node.cton

@@ -1,15 +1,19 @@
 ; For testing cfg generation where some block is never reached.
 
 function not_reached(i32) -> i32 {
+; check: digraph not_reached {
+; check:     ebb0 [shape=record, label="{ebb0 | <inst0>brnz ebb2}"]
+; check:     ebb1 [shape=record, label="{ebb1 | <inst4>jump ebb0}"]
+; check:     ebb2 [shape=record, label="{ebb2}"]
 
 ebb0(v0: i32):
-    brnz v0, ebb2       ;;;; ebb0:inst0 -> ebb2
+    brnz v0, ebb2       ; unordered: ebb0:inst0 -> ebb2
     trap
 
 ebb1:
     v1 = iconst.i32 1
     v2 = iadd v0, v1
-    jump ebb0(v2)       ;;;; ebb1:inst4 -> ebb0
+    jump ebb0(v2)       ; unordered: ebb1:inst4 -> ebb0
 
 ebb2:
     return v0