From 514b3147bf08817d17aacc492be255621209ec8b Mon Sep 17 00:00:00 2001
From: Cliff Click <cliffc@acm.org>
Date: Wed, 7 Oct 2026 12:37:06 -0700
Subject: RoundF32 actually rounds

---
 .../com/seaofnodes/simple/node/RoundF32Node.java   |  1 +
 .../com/seaofnodes/simple/type/TypeStruct.java     |  2 +-
 .../java/com/seaofnodes/simple/Chapter18Test.java  | 27 ++++++++++++++++++++++
 3 files changed, 29 insertions(+), 1 deletion(-)

(limited to 'chapter18/src')

diff --git a/chapter18/src/main/java/com/seaofnodes/simple/node/RoundF32Node.java b/chapter18/src/main/java/com/seaofnodes/simple/node/RoundF32Node.java
index 78e7698c..10a0e4aa 100644
--- a/chapter18/src/main/java/com/seaofnodes/simple/node/RoundF32Node.java
+++ b/chapter18/src/main/java/com/seaofnodes/simple/node/RoundF32Node.java
@@ -16,6 +16,7 @@ public class RoundF32Node extends Node {
     public Type compute() {
         if (in(1)._type instanceof TypeFloat i0 && i0.isConstant() )
             return TypeFloat.constant((float)i0.value());
+        if( in(1)._type==TypeFloat.F64 ) return TypeFloat.F32;
         return in(1)._type;
     }
 
diff --git a/chapter18/src/main/java/com/seaofnodes/simple/type/TypeStruct.java b/chapter18/src/main/java/com/seaofnodes/simple/type/TypeStruct.java
index bc640955..fff6a7db 100644
--- a/chapter18/src/main/java/com/seaofnodes/simple/type/TypeStruct.java
+++ b/chapter18/src/main/java/com/seaofnodes/simple/type/TypeStruct.java
@@ -49,7 +49,7 @@ public class TypeStruct extends Type {
 
     // Array
     public static TypeStruct makeAry(TypeInteger len, int lenAlias, Type body, int bodyAlias) {
-        assert body instanceof TypeInteger || (body instanceof TypeNil tn && tn.nullable());
+        assert body instanceof TypeInteger || body instanceof TypeFloat || (body instanceof TypeNil tn && tn.nullable());
         return make("[" + body.str() + "]",
                     Field.make("#" ,len , lenAlias,true ),
                     Field.make("[]",body,bodyAlias,false));
diff --git a/chapter18/src/test/java/com/seaofnodes/simple/Chapter18Test.java b/chapter18/src/test/java/com/seaofnodes/simple/Chapter18Test.java
index c4d5b9ac..0758fbf5 100644
--- a/chapter18/src/test/java/com/seaofnodes/simple/Chapter18Test.java
+++ b/chapter18/src/test/java/com/seaofnodes/simple/Chapter18Test.java
@@ -9,6 +9,33 @@ import static org.junit.Assert.fail;
 import org.junit.Ignore;
 
 public class Chapter18Test {
+    @Test public void testFloatArrays() {
+        for( String type : new String[]{"flt","f64","f32"} ) {
+            CodeGen zero = new CodeGen("var a = new "+type+"[arg]; return a[arg-1];")
+                .parse().opto().typeCheck();
+            assertEquals("0.0",Eval2.eval(zero,3));
+            // Eval2 does not execute RoundF32 yet; check nonconstant narrowing here.
+            new CodeGen(type+" x = arg; var a = new "+type+"[arg]; a[0] = x; return a[0];")
+                .parse().opto().typeCheck();
+        }
+        for( String type : new String[]{"flt","f64"} ) {
+            CodeGen loop = new CodeGen("var a = new "+type+"[arg]; "+
+                "for(int i=0; i<arg; i++) a[i] += i+0.25; return a[0]+a[arg-1];")
+                .parse().opto().typeCheck();
+            assertEquals("0.5",Eval2.eval(loop,1));
+            assertEquals("3.5",Eval2.eval(loop,4));
+
+            CodeGen rounded = new CodeGen("var a = new "+type+"[arg]; "+
+                "for(int i=0; i<arg; i++) a[i] = 16777216.0+i; return a[arg-1];")
+                .parse().opto().typeCheck();
+            assertEquals("1.6777217E7",Eval2.eval(rounded,2));
+        }
+        CodeGen rounded = new CodeGen("var a = new f32[arg]; "+
+            "for(int i=0; i<arg; i++) a[i] = 16777217.0; return a[arg-1];")
+            .parse().opto().typeCheck();
+        assertEquals("1.6777216E7",Eval2.eval(rounded,2));
+    }
+
     @Test public void testNeverExitLoopDepth() {
         String[] sources = {
             "if(arg) while(1) {} return 7;",
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