Chapter 5: If Statement, Phi, and Region

Co-authored-by: Dibyendu Majumdar <mobile@majumdar.org.uk>
Co-authored-by: XmiliaH <45106915+XmiliaH@users.noreply.github.com>
Co-authored-by: Yichen Yan <oraluben@outlook.com>
Co-authored-by: Thalia Archibald <thalia@archibald.dev>
Co-authored-by: Hsiang-Ying Fu <66062782+fuhsnn@users.noreply.github.com>
Co-authored-by: Tamas Hadhazy <helsgithub15@gmail.com>
Co-authored-by: Symious <14933944+symious@users.noreply.github.com>
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
Co-authored-by: tannal <tannal2409@gmail.com>
Co-authored-by: hadha <helsgithub15@gmail.com>
Co-authored-by: fuhsnn <66062782+fuhsnn@users.noreply.github.com>
Co-authored-by: Tamás Hadházy <85063808+Hels15@users.noreply.github.com>
Co-authored-by: RobertObkircher <robert.obkircher@gmail.com>
Co-authored-by: Jun Kawasaki <jun784@gmail.com>
Co-authored-by: David Rubin <87927264+Rexicon226@users.noreply.github.com>

5 files changed, 260 insertions, 33 deletions

diff --git a/src/test/java/com/seaofnodes/simple/Chapter01Test.java b/src/test/java/com/seaofnodes/simple/Chapter01Test.java
index 3d568337..547c36f8 100644
--- a/src/test/java/com/seaofnodes/simple/Chapter01Test.java
+++ b/src/test/java/com/seaofnodes/simple/Chapter01Test.java
@@ -11,8 +11,9 @@ public class Chapter01Test {
     @Test
     public void testSimpleProgram() {
         Parser parser = new Parser("return 1;");
-        ReturnNode ret = parser.parse();
+        StopNode stop = parser.parse();
         StartNode start = Parser.START;
+        ReturnNode ret = (ReturnNode)stop.in(0);
 
         assertTrue(ret.ctrl() instanceof ProjNode);
         Node expr = ret.expr();
diff --git a/src/test/java/com/seaofnodes/simple/Chapter02Test.java b/src/test/java/com/seaofnodes/simple/Chapter02Test.java
index 6c816a23..a6075b75 100644
--- a/src/test/java/com/seaofnodes/simple/Chapter02Test.java
+++ b/src/test/java/com/seaofnodes/simple/Chapter02Test.java
@@ -11,49 +11,49 @@ public class Chapter02Test {
     @Test
     public void testParseGrammar() {
         Parser parser = new Parser("return 1+2*3+-5;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return 2;", ret.print());
     }
 
     @Test
     public void testAddPeephole() {
         Parser parser = new Parser("return 1+2;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return 3;", ret.print());
     }
 
     @Test
     public void testSubPeephole() {
         Parser parser = new Parser("return 1-2;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return -1;", ret.print());
     }
 
     @Test
     public void testMulPeephole() {
         Parser parser = new Parser("return 2*3;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return 6;", ret.print());
     }
 
     @Test
     public void testDivPeephole() {
         Parser parser = new Parser("return 6/3;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return 2;", ret.print());
     }
 
     @Test
     public void testMinusPeephole() {
         Parser parser = new Parser("return 6/-3;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return -2;", ret.print());
     }
 
     @Test
     public void testExample() {
         Parser parser = new Parser("return 1+2*3+-5;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return 2;", ret.print());
     }
 
diff --git a/src/test/java/com/seaofnodes/simple/Chapter03Test.java b/src/test/java/com/seaofnodes/simple/Chapter03Test.java
index 46b1ca33..c3cd43c3 100644
--- a/src/test/java/com/seaofnodes/simple/Chapter03Test.java
+++ b/src/test/java/com/seaofnodes/simple/Chapter03Test.java
@@ -11,28 +11,28 @@ public class Chapter03Test {
     @Test
     public void testVarDecl() {
         Parser parser = new Parser("int a=1; return a;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return 1;", ret.print());
     }
 
     @Test
     public void testVarAdd() {
         Parser parser = new Parser("int a=1; int b=2; return a+b;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return 3;", ret.print());
     }
 
     @Test
     public void testVarScope() {
         Parser parser = new Parser("int a=1; int b=2; int c=0; { int b=3; c=a+b; } return c;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return 4;", ret.print());
     }
 
     @Test
     public void testVarDist() {
         Parser parser = new Parser("int x0=1; int y0=2; int x1=3; int y1=4; return (x0-x1)*(x0-x1) + (y0-y1)*(y0-y1);");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return 8;", ret.print());
     }
 
diff --git a/src/test/java/com/seaofnodes/simple/Chapter04Test.java b/src/test/java/com/seaofnodes/simple/Chapter04Test.java
index 195afbb7..e5840622 100644
--- a/src/test/java/com/seaofnodes/simple/Chapter04Test.java
+++ b/src/test/java/com/seaofnodes/simple/Chapter04Test.java
@@ -11,77 +11,78 @@ public class Chapter04Test {
     @Test
     public void testPeephole() {
         Parser parser = new Parser("return 1+arg+2;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return (arg+3);", ret.print());
     }
 
     @Test
     public void testPeephole2() {
         Parser parser = new Parser("return (1+arg)+2;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return (arg+3);", ret.print());
     }
 
     @Test
     public void testAdd0() {
         Parser parser = new Parser("return 0+arg;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return arg;", ret.print());
     }
 
     @Test
     public void testAddAddMul() {
         Parser parser = new Parser("return arg+0+arg;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return (arg*2);", ret.print());
     }
 
     @Test
     public void testPeephole3() {
         Parser parser = new Parser("return 1+arg+2+arg+3;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return ((arg*2)+6);", ret.print());
     }
 
     @Test
     public void testMul1() {
         Parser parser = new Parser("return 1*arg;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return arg;", ret.print());
     }
 
     @Test
     public void testSub0() {
         Parser parser = new Parser("return arg-0;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return arg;", ret.print());
     }
 
     @Test
     public void test0Sub() {
         Parser parser = new Parser("return 0-arg;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return (-arg);", ret.print());
     }
 
     @Test
     public void testSubNeg() {
         Parser parser = new Parser("return 3--arg;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return (arg+3);", ret.print());
     }
 
     @Test
     public void testNegSub() {
         Parser parser = new Parser("return -arg-3;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return (-(arg+3));", ret.print());
     }
 
     @Test
     public void testVarArg() {
-        Parser parser = new Parser("return arg;", TypeInteger.BOT);
-        ReturnNode ret = parser.parse();
+        Parser parser = new Parser("return arg;");
+        StopNode stop = parser.parse();
+        ReturnNode ret = stop.ret();
         assertTrue(ret.in(0) instanceof ProjNode);
         assertTrue(ret.in(1) instanceof ProjNode);
     }
@@ -89,49 +90,49 @@ public class Chapter04Test {
     @Test
     public void testConstantArg() {
         Parser parser = new Parser("return arg;", TypeInteger.constant(2));
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return 2;", ret.print());
     }
 
     @Test
     public void testCompEq() {
         Parser parser = new Parser("return 3==3;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return 1;", ret.print());
     }
 
     @Test
     public void testCompEq2() {
         Parser parser = new Parser("return 3==4;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return 0;", ret.print());
     }
 
     @Test
     public void testCompNEq() {
         Parser parser = new Parser("return 3!=3;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return 0;", ret.print());
     }
 
     @Test
     public void testCompNEq2() {
         Parser parser = new Parser("return 3!=4;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return 1;", ret.print());
     }
 
     @Test
     public void testBug1() {
         Parser parser = new Parser("int a=arg+1; int b=a; b=1; return a+2;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return (arg+3);", ret.print());
     }
 
     @Test
     public void testBug2() {
         Parser parser = new Parser("int a=arg+1; a=a; return a;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return (arg+1);", ret.print());
     }
 
@@ -148,14 +149,14 @@ public class Chapter04Test {
     @Test
     public void testBug4() {
         Parser parser = new Parser("return -arg;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return (-arg);", ret.print());
     }
 
     @Test
     public void testBug5() {
         Parser parser = new Parser("return arg--2;");
-        ReturnNode ret = parser.parse();
+        StopNode ret = parser.parse();
         assertEquals("return (arg--2);", ret.print());
     }
 }
diff --git a/src/test/java/com/seaofnodes/simple/Chapter05Test.java b/src/test/java/com/seaofnodes/simple/Chapter05Test.java
new file mode 100644
index 00000000..d6c91a4a
--- /dev/null
+++ b/src/test/java/com/seaofnodes/simple/Chapter05Test.java
@@ -0,0 +1,225 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.TypeInteger;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class Chapter05Test {
+
+    @Test
+    public void testIfStmt() {
+        Parser parser = new Parser(
+"""
+int a = 1;
+if (arg == 1)
+    a = arg+2;
+else {
+    a = arg-3;
+}
+return a;""");
+        StopNode ret = parser.parse();
+        assertEquals("return Phi(Region17,(arg+2),(arg-3));", ret.toString());
+    }
+
+    @Test
+    public void testTest() {
+        Parser parser = new Parser(
+"""
+int c = 3;
+int b = 2;
+if (arg == 1) {
+    b = 3;
+    c = 4;
+}
+return c;""", TypeInteger.BOT);
+        StopNode ret = parser.parse();
+        assertEquals("return Phi(Region16,4,3);", ret.toString());
+    }
+
+    @Test
+    public void testReturn2() {
+        Parser parser = new Parser(
+"""
+if( arg==1 )
+    return 3;
+else
+    return 4;
+""", TypeInteger.BOT);
+        StopNode stop = parser.parse();
+        assertEquals("Stop[ return 3; return 4; ]", stop.toString());
+    }
+
+    @Test
+    public void testIfMergeB() {
+        Parser parser = new Parser(
+"""
+int a=arg+1;
+int b=0;
+if( arg==1 )
+    b=a;
+else
+    b=a+1;
+return a+b;""");
+        StopNode ret = parser.parse();
+        assertEquals("return ((arg*2)+Phi(Region20,2,3));", ret.toString());
+    }
+
+    @Test
+    public void testIfMerge2() {
+        Parser parser = new Parser(
+"""
+int a=arg+1;
+int b=arg+2;
+if( arg==1 )
+    b=b+a;
+else
+    a=b+1;
+return a+b;""");
+        StopNode ret = parser.parse();
+        assertEquals("return ((Phi(Region31,(arg*2),arg)+arg)+Phi(Region,4,5));", ret.toString());
+    }
+
+    @Test
+    public void testMerge3() {
+        Parser parser = new Parser(
+"""
+int a=1;
+if( arg==1 )
+    if( arg==2 )
+        a=2;
+    else
+        a=3;
+else if( arg==3 )
+    a=4;
+else
+    a=5;
+return a;
+""", TypeInteger.BOT);
+        StopNode stop = parser.parse();
+        assertEquals("return Phi(Region33,Phi(Region21,2,3),Phi(Region31,4,5));", stop.toString());
+    }
+
+    @Test
+    public void testMerge4() {
+        Parser parser = new Parser(
+"""
+int a=0;
+int b=0;
+if( arg )
+    a=1;
+if( arg==0 )
+    b=2;
+return arg+a+b;
+""", TypeInteger.BOT);
+        StopNode stop = parser.parse();
+        assertEquals("return ((arg+Phi(Region13,1,0))+Phi(Region22,2,0));", stop.toString());
+    }
+
+    @Test
+    public void testMerge5() {
+        Parser parser = new Parser(
+"""
+int a=arg==2;
+if( arg==1 )
+{
+    a=arg==3;
+}
+return a;""");
+        StopNode ret = parser.parse();
+        assertEquals("return (arg==Phi(Region16,3,2));", ret.toString());
+    }
+
+    @Test
+    public void testMergeSameCon() {
+        Parser parser = new Parser(
+"""
+int a=arg;
+if( arg==1 )
+    a=3;
+else
+    a=3;
+return a;
+""");
+        StopNode ret = parser.parse();
+        assertEquals("return 3;", ret.toString());
+    }
+
+    @Test
+    public void testTrue() {
+      StopNode stop = new Parser("return true;").parse();
+      assertEquals("return 1;",stop.toString());
+    }
+
+    @Test
+    public void testHalfDef() {
+        try {
+            new Parser("if( arg==1 ) int b=2; return b;").parse();
+            fail();
+        } catch( RuntimeException e ) {
+            assertEquals("Cannot define a new name on one arm of an if",e.getMessage());
+        }
+    }
+
+    @Test
+    public void testHalfDef2() {
+        try {
+            new Parser("if( arg==1 ) { int b=2; } else { int b=3; } return b;").parse();
+            fail();
+        } catch( RuntimeException e ) {
+            assertEquals("Undefined name 'b'",e.getMessage());
+        }
+    }
+
+    @Test
+    public void testRegress1() {
+        try {
+            new Parser("if(arg==2) int a=1; else int b=2; return a;").parse();
+            fail();
+        } catch( RuntimeException e ) {
+            assertEquals("Cannot define a new name on one arm of an if",e.getMessage());
+        }
+    }
+
+    @Test
+    public void testBadNum() {
+        try {
+            new Parser("return 1-;").parse();
+            fail();
+        } catch( RuntimeException e ) {
+            assertEquals("Syntax error, expected an identifier or expression: ;",e.getMessage());
+        }
+    }
+
+    @Test
+    public void testKeyword1() {
+        try {
+            new Parser("int true=0; return true;").parse();
+            fail();
+        } catch( RuntimeException e ) {
+            assertEquals("Expected an identifier, found 'true'",e.getMessage());
+        }
+    }
+
+    @Test
+    public void testKeyword2() {
+        try {
+            new Parser("int else=arg; if(else) else=2; else else=1; return else;").parse();
+            fail();
+        } catch( RuntimeException e ) {
+            assertEquals("Expected an identifier, found 'else'",e.getMessage());
+        }
+    }
+
+    @Test
+    public void testKeyword3() {
+        try {
+            new Parser("int a=1; ififif(arg)inta=2;return a;").parse();
+            fail();
+        } catch( RuntimeException e ) {
+            assertEquals("Syntax error, expected =: (",e.getMessage());
+        }
+    }
+
+}