fix: Coerce NaN to false when casting to bool (#1437)

Author: MaxGraey

src/compiler.ts

@@ -3682,7 +3682,7 @@ export class Compiler extends DiagnosticEmitter {
         // f32 to int
         if (fromType.kind == TypeKind.F32) {
           if (toType.isBooleanValue) {
-            expr = module.binary(BinaryOp.NeF32, expr, module.f32(0));
+            expr = this.makeIsTrueish(expr, Type.f32, reportNode);
             wrap = false;
           } else if (toType.isSignedIntegerValue) {
             if (toType.isLongIntegerValue) {
@@ -3701,7 +3701,7 @@ export class Compiler extends DiagnosticEmitter {
         // f64 to int
         } else {
           if (toType.isBooleanValue) {
-            expr = module.binary(BinaryOp.NeF64, expr, module.f64(0));
+            expr = this.makeIsTrueish(expr, Type.f64, reportNode);
             wrap = false;
           } else if (toType.isSignedIntegerValue) {
             if (toType.isLongIntegerValue) {
@@ -10790,32 +10790,38 @@ export class Compiler extends DiagnosticEmitter {
           : expr;
       }
       case TypeKind.F32: {
-        // (x != 0.0) & (x == x)
-        let flow = this.currentFlow;
-        let temp = flow.getTempLocal(Type.f32);
-        let ret = module.binary(BinaryOp.AndI32,
-          module.binary(BinaryOp.NeF32, module.local_tee(temp.index, expr), module.f32(0)),
-          module.binary(BinaryOp.EqF32,
-            module.local_get(temp.index, NativeType.F32),
-            module.local_get(temp.index, NativeType.F32)
-          )
+        // 0 < abs(bitCast(x)) <= bitCast(Infinity) or
+        // (reinterpret<u32>(x) & 0x7FFFFFFF) - 1 <= 0x7F800000 - 1
+        //
+        // and finally:
+        // (reinterpret<u32>(x) << 1) - (1 << 1) <= ((0x7F800000 - 1) << 1)
+        return module.binary(BinaryOp.LeU32,
+          module.binary(BinaryOp.SubI32,
+            module.binary(BinaryOp.ShlI32,
+              module.unary(UnaryOp.ReinterpretF32, expr),
+              module.i32(1)
+            ),
+            module.i32(2) // 1 << 1
+          ),
+          module.i32(0xFEFFFFFE) // (0x7F800000 - 1) << 1
         );
-        flow.freeTempLocal(temp);
-        return ret;
       }
       case TypeKind.F64: {
-        // (x != 0.0) & (x == x)
-        let flow = this.currentFlow;
-        let temp = flow.getTempLocal(Type.f64);
-        let ret = module.binary(BinaryOp.AndI32,
-          module.binary(BinaryOp.NeF64, module.local_tee(temp.index, expr), module.f64(0)),
-          module.binary(BinaryOp.EqF64,
-            module.local_get(temp.index, NativeType.F64),
-            module.local_get(temp.index, NativeType.F64)
-          )
+        // 0 < abs(bitCast(x)) <= bitCast(Infinity) or
+        // (reinterpret<u64>(x) & 0x7FFFFFFFFFFFFFFF) - 1 <= 0x7FF0000000000000 - 1
+        //
+        // and finally:
+        // (reinterpret<u64>(x) << 1) - (1 << 1) <= ((0x7FF0000000000000 - 1) << 1)
+        return module.binary(BinaryOp.LeU64,
+          module.binary(BinaryOp.SubI64,
+            module.binary(BinaryOp.ShlI64,
+              module.unary(UnaryOp.ReinterpretF64, expr),
+              module.i64(1)
+            ),
+            module.i64(2) // 1 << 1
+          ),
+          module.i64(0xFFFFFFFE, 0xFFDFFFFF) // (0x7FF0000000000000 - 1) << 1
         );
-        flow.freeTempLocal(temp);
-        return ret;
       }
       case TypeKind.EXTERNREF: {
         // TODO: non-null object might still be considered falseish

tests/compiler/bool.ts

@@ -6,9 +6,68 @@ var u = <u32>2;
 assert(<bool>u == true);
 var U = <u64>2;
 assert(<bool>U == true);
+
 var f = <f32>2;
 assert(<bool>f == true);
+var f0 = <f32>+0.0;
+assert(<bool>f0 == false);
+var f1 = <f32>-0.0;
+assert(<bool>f1 == false);
+var f2 = <f32>+NaN;
+assert(<bool>f2 == false);
+var f3 = <f32>-NaN;
+assert(<bool>f3 == false);
+var f4 = +f32.MAX_VALUE;
+assert(<bool>f4 == true);
+var f5 = -f32.MAX_VALUE;
+assert(<bool>f5 == true);
+var f6 = <f32>+Infinity;
+assert(<bool>f6 == true);
+var f7 = <f32>-Infinity;
+assert(<bool>f7 == true);
+var f8 = +f32.MIN_VALUE;
+assert(<bool>f8 == true);
+var f9 = -f32.MIN_VALUE;
+assert(<bool>f9 == true);
+var f10 = reinterpret<f32>(1);
+assert(<bool>f10 == true);
+var f11 = reinterpret<f32>(0x7F800000 - 1);
+assert(<bool>f11 == true);
+var f12 = reinterpret<f32>(0x7F800000 + 1);
+assert(<bool>f12 == false);
+var f13 = reinterpret<f32>(0xFF800000 + 1);
+assert(<bool>f13 == false);
+
 var F = <f64>2;
 assert(<bool>F == true);
+var F0 = <f64>+0.0;
+assert(<bool>F0 == false);
+var F1 = <f64>-0.0;
+assert(<bool>F1 == false);
+var F2 = <f64>+NaN;
+assert(<bool>F2 == false);
+var F3 = <f64>-NaN;
+assert(<bool>F3 == false);
+var F4 = +f64.MAX_VALUE;
+assert(<bool>F4 == true);
+var F5 = -f64.MAX_VALUE;
+assert(<bool>F5 == true);
+var F6 = +Infinity;
+assert(<bool>F6 == true);
+var F7 = -Infinity;
+assert(<bool>F7 == true);
+var F8 = +f64.MIN_VALUE;
+assert(<bool>F8 == true);
+var F9 = -f64.MIN_VALUE;
+assert(<bool>F9 == true);
+var F10 = reinterpret<f64>(1);
+assert(<bool>F10 == true);
+var F11 = reinterpret<f64>(0x7FF0000000000000 - 1);
+assert(<bool>F11 == true);
+var F12 = reinterpret<f64>(0x7FF0000000000000 + 1);
+assert(<bool>F12 == false);
+var F13 = reinterpret<f64>(0xFFF0000000000000 + 1);
+assert(<bool>F13 == false);
+
 var uu = <u8>2;
 assert(<bool>uu == true);