missing null check

2 files changed, 121 insertions, 2 deletions

diff --git a/chapter12/src/main/java/com/seaofnodes/simple/node/PhiNode.java b/chapter12/src/main/java/com/seaofnodes/simple/node/PhiNode.java
index 535db980..ebed8dd1 100644
--- a/chapter12/src/main/java/com/seaofnodes/simple/node/PhiNode.java
+++ b/chapter12/src/main/java/com/seaofnodes/simple/node/PhiNode.java
@@ -103,7 +103,7 @@ public class PhiNode extends Node {
                 if( region().idom(this) instanceof IfNode iff && iff.pred().addDep(this)==val ) {
                     // Must walk the idom on the null side to make sure we hit False.
                     CFGNode idom = (CFGNode)region().in(nullx);
-                    while( idom.in(0) != iff ) idom = idom.idom();
+                    while( idom.nIns() > 0 && idom.in(0) != iff ) idom = idom.idom();
                     if( idom instanceof CProjNode proj && proj._idx==1 )
                         return val;
                 }
diff --git a/chapter12/src/test/java/com/seaofnodes/simple/Chapter12Test.java b/chapter12/src/test/java/com/seaofnodes/simple/Chapter12Test.java
index 92ed9031..a41fae91 100644
--- a/chapter12/src/test/java/com/seaofnodes/simple/Chapter12Test.java
+++ b/chapter12/src/test/java/com/seaofnodes/simple/Chapter12Test.java
@@ -13,7 +13,126 @@ public class Chapter12Test {
     public void testJig() {
         Parser parser = new Parser(
 """
-return 3.14
+arg=0;
+struct fxaV1Ic3 {
+}
+fxaV1Ic3 tKRUMAeM=new fxaV1Ic3;
+tKRUMAeM=tKRUMAeM;
+while(2>0*-0<-arg<=false) if(-arg) if(-arg<=(-arg)) {
+            arg=(-arg);
+            while(false) {
+            }
+            {
+                {}
+                while(arg<arg>=(false/97)) break;
+                break;
+            }
+        }
+int eKG4lqt=-arg<--1<=----2;
+eKG4lqt=-6;
+int arg=--(--false<--0)<eKG4lqt>5;
+eKG4lqt=-0;
+{
+    tKRUMAeM=new fxaV1Ic3;
+    arg=-(-arg);
+    flt erpUhf=0.9873326;
+    {
+        while(-false*arg-eKG4lqt!=58) if(----eKG4lqt) erpUhf=-0.84418744/erpUhf;
+            else if(48>=eKG4lqt<=1/14----eKG4lqt) break;
+                else break;
+        erpUhf=(erpUhf)--0.35600418*--(erpUhf);
+        if(-0/-eKG4lqt>=eKG4lqt---arg-arg) {
+            if(--arg+7+--arg) {
+            }
+            else while(-1) erpUhf=erpUhf;
+            tKRUMAeM=(tKRUMAeM);
+            int rwPI=-eKG4lqt<=-(eKG4lqt+true);
+        }
+        if(false<=---8==--(false!=--arg)>=2) {
+            return ---erpUhf==erpUhf;
+        }
+        erpUhf=-erpUhf;
+    }
+    {
+        int U=-10+-----0!=eKG4lqt+25-13<-arg--eKG4lqt>=--arg;
+        while(U<-0+(---true<=eKG4lqt<=-50>=false)) {
+            U=U+-U!=-12<--(--43>=(false));
+            if((eKG4lqt)>(---U*eKG4lqt<=0!=--arg)/-U) {
+                erpUhf=-erpUhf+-erpUhf;
+                if(-(--U)!=--arg+U>---arg>=true*-(--40!=-eKG4lqt<U+--6)) while(6/---U>=--1-62) erpUhf=-----(--0.87431<erpUhf>=-0.04622048<-0.7782522)-erpUhf*0.8976203+-0.26186156>erpUhf<0.23554772!=-0.37699592;
+            }
+            {
+                int Su5Ap9KHJ=-U;
+                while(Su5Ap9KHJ<---U) {
+                    Su5Ap9KHJ=Su5Ap9KHJ+32+---eKG4lqt;
+                }
+            }
+            if(-true--2) {
+                tKRUMAeM=new fxaV1Ic3;
+                while(true>U) continue;
+            }
+            else {
+                fxaV1Ic3? DN8J9B=tKRUMAeM;
+                flt eKG4lqt=0.17164475<erpUhf;
+                {
+                    if(!DN8J9B)DN8J9B=null;
+                    else arg=U;
+                }
+                {
+                    int CEdri=-U>12!=-arg;
+                    while(CEdri<CEdri) {
+                        CEdri=CEdri+--51;
+                        if(!DN8J9B)erpUhf=--eKG4lqt;
+                    }
+                }
+                U=-0;
+            }
+            fxaV1Ic3 RDAPoRG=tKRUMAeM;
+            {
+                int eKG4lqt=arg!=---U;
+                while(eKG4lqt<arg*----(-eKG4lqt==--U*-U)>=false-5==-arg) {
+                    eKG4lqt=eKG4lqt+-----arg;
+                    while(U) {
+                        while(15*-----4) U=--arg;
+                        int gQqFyu1=--eKG4lqt;
+                    }
+                    {
+                        int RDAPoRG=arg*0<--false;
+                        while(RDAPoRG<--arg) {
+                            RDAPoRG=RDAPoRG+--eKG4lqt;
+                            eKG4lqt=--U;
+                        }
+                    }
+                    if(14==arg<-3-true) while(2<=----false<=arg) return -erpUhf;
+                    else arg=U;
+                    if(-U) {
+                        break;
+                    }
+                    {
+                        if(2>eKG4lqt/arg!=--false<=--eKG4lqt) continue;
+                        else erpUhf=-0.6544298;
+                        eKG4lqt=--0==---U>=U*eKG4lqt==arg-arg;
+                        if(-eKG4lqt) break;
+                        else break;
+                    }
+                }
+            }
+            fxaV1Ic3? o0a0L;
+            arg=--eKG4lqt;
+            break;
+        }
+    }
+    if(-((-arg)<=eKG4lqt)) while(--eKG4lqt) arg=---eKG4lqt!=5<-eKG4lqt;
+    else return -arg;
+    if(30) eKG4lqt=16>=-----arg!=-true<(eKG4lqt);
+    flt l=0.17984325*-0.88223094;
+    flt lg97e=l>-(--0.017727911==0.9812363)-(erpUhf!=-----0.19494736);
+    erpUhf=--erpUhf!=---0.3488902;
+    int DW=eKG4lqt==---eKG4lqt;
+    if(DW*7<25*-22!=----96!=-2) return ---erpUhf;
+    else return -DW/-arg;
+}
+//return 3.14;
 """);
         StopNode stop = parser.parse(false).iterate(false);
         assertEquals("return 3.14;", stop.toString());