diff --git a/lib/std/core/mem.c3 b/lib/std/core/mem.c3
index 8fa1c2683..b537fdd5c 100644
--- a/lib/std/core/mem.c3
+++ b/lib/std/core/mem.c3
@@ -746,39 +746,39 @@ fn void* tmalloc(usz size, usz alignment = 0) @builtin @inline @nodiscard
 
 <*
  @param $Type : "The type to allocate"
+ @param #init : "The optional initializer"
 
- @require $vacount < 2 : "Too many arguments."
- @require $vacount == 0 ||| $defined($Type a = $vaexpr[0]) : "The second argument must be an initializer for the type"
+ @require !$defined(#init) ||| $defined($Type a = #init) : "#init must be an initializer for the type"
  @require $Type.alignof <= DEFAULT_MEM_ALIGNMENT : "Types with alignment exceeding the default must use 'alloc_aligned' instead"
  @return "A pointer to data of type $Type."
 *>
-macro new($Type, ...) @nodiscard
+macro new($Type, #init = ...) @nodiscard @safemacro
 {
-	$if $vacount == 0:
-		return ($Type*)calloc($Type.sizeof);
-	$else
+	$if $defined(#init):
 		$Type* val = malloc($Type.sizeof);
-		*val = $vaexpr[0];
+		*val = #init;
 		return val;
+	$else
+		return ($Type*)calloc($Type.sizeof);
 	$endif
 }
 
 <*
  @param $Type : "The type to allocate"
  @param padding : "The padding to add after the allocation"
+ @param #init : "The optional initializer"
 
- @require $vacount < 2 : "Too many arguments."
- @require $vacount == 0 ||| $defined($Type a = $vaexpr[0]) : "The second argument must be an initializer for the type"
+ @require !$defined(#init) ||| $defined($Type a = #init) : "#init must be an initializer for the type"
  @return "A pointer to data of type $Type."
 *>
-macro new_with_padding($Type, usz padding, ...) @nodiscard
+macro new_with_padding($Type, usz padding, #init = ...) @nodiscard @safemacro
 {
-	$if $vacount == 0:
-		return ($Type*)calloc($Type.sizeof + padding);
-	$else
+	$if $defined(#init):
 		$Type* val = malloc($Type.sizeof + padding);
-		*val = $vaexpr[0];
+		*val = #init;
 		return val;
+	$else
+		return ($Type*)calloc($Type.sizeof + padding);
 	$endif
 }
 
@@ -787,19 +787,19 @@ macro new_with_padding($Type, usz padding, ...) @nodiscard
  exceeding DEFAULT_MEM_ALIGNMENT. IMPORTANT! It must be freed using free_aligned.
 
  @param $Type : "The type to allocate"
+ @param #init : "The optional initializer"
 
- @require $vacount < 2 : "Too many arguments."
- @require $vacount == 0 ||| $defined($Type a = $vaexpr[0]) : "The second argument must be an initializer for the type"
+ @require !$defined(#init) ||| $defined($Type a = #init) : "#init must be an initializer for the type"
  @return "A pointer to data of type $Type with the proper alignment"
 *>
-macro new_aligned($Type, ...) @nodiscard
+macro new_aligned($Type, #init = ...) @nodiscard @safemacro
 {
-	$if $vacount == 0:
-		return ($Type*)calloc_aligned($Type.sizeof, $Type.alignof);
-	$else
+	$if $defined(#init):
 		$Type* val = malloc_aligned($Type.sizeof, $Type.alignof);
-		*val = $vaexpr[0];
+		*val = #init;
 		return val;
+	$else
+		return ($Type*)calloc_aligned($Type.sizeof, $Type.alignof);
 	$endif
 }
 
@@ -841,38 +841,38 @@ macro alloc_aligned($Type) @nodiscard
 
 <*
  @param $Type : "The type to allocate"
+ @param #init : "The optional initializer"
 
- @require $vacount < 2 : "Too many arguments."
- @require $vacount == 0 ||| $defined($Type a = $vaexpr[0]) : "The second argument must be an initializer for the type"
+ @require !$defined(#init) ||| $defined($Type a = #init) : "#init must be an initializer for the type"
  @return "A pointer to temporary data of type $Type."
 *>
-macro tnew($Type, ...) @nodiscard
+macro tnew($Type, #init = ...) @nodiscard @safemacro
 {
-	$if $vacount == 0:
-		return ($Type*)tcalloc($Type.sizeof, $Type.alignof) @inline;
-	$else
+	$if $defined(#init):
 		$Type* val = tmalloc($Type.sizeof, $Type.alignof) @inline;
-		*val = $vaexpr[0];
+		*val = #init;
 		return val;
+	$else
+		return ($Type*)tcalloc($Type.sizeof, $Type.alignof) @inline;
 	$endif
 }
 
 <*
  @param $Type : "The type to allocate"
  @param padding : "The padding to add after the allocation"
+ @param #init : "The optional initializer"
 
-@require $vacount < 2 : "Too many arguments."
- @require $vacount == 0 ||| $defined($Type a = $vaexpr[0]) : "The second argument must be an initializer for the type"
+ @require !$defined(#init) ||| $defined($Type a = #init) : "#init must be an initializer for the type"
  @return "A pointer to temporary data of type $Type with added padding at the end."
 *>
-macro temp_with_padding($Type, usz padding, ...) @nodiscard
+macro temp_with_padding($Type, usz padding, #init = ...) @nodiscard @safemacro
 {
-	$if $vacount == 0:
-		return ($Type*)tcalloc($Type.sizeof + padding, $Type.alignof) @inline;
-	$else
+	$if $defined(#init):
 		$Type* val = tmalloc($Type.sizeof + padding, $Type.alignof) @inline;
-		*val = $vaexpr[0];
+		*val = #init;
 		return val;
+	$else
+		return ($Type*)tcalloc($Type.sizeof + padding, $Type.alignof) @inline;
 	$endif
 }
 
diff --git a/lib/std/math/math_nolibc/round.c3 b/lib/std/math/math_nolibc/round.c3
index 31ea82e58..75c9872c6 100644
--- a/lib/std/math/math_nolibc/round.c3
+++ b/lib/std/math/math_nolibc/round.c3
@@ -31,7 +31,8 @@ fn float _roundf(float x) @extern("roundf") @weak @nostrip
 	uint u = bitcast(x, uint);
 	int e = (u >> 23) & 0xff;
 	if (e >= 0x7f + 23) return x;
-	if (u >> 31) x = -x;
+	bool signed = u >> 31 != 0;
+	if (signed) x = -x;
 	if (e < 0x7f - 1)
 	{
 		force_eval_add(x, TOINTF);
@@ -47,7 +48,7 @@ fn float _roundf(float x) @extern("roundf") @weak @nostrip
 		default:
 			y = y + x;
 	}
-	if (u >> 31) y = -y;
+	if (signed) y = -y;
 	return y;
 }
 
diff --git a/lib/std/math/runtime/math_supplemental.c3 b/lib/std/math/runtime/math_supplemental.c3
index 4093256fe..2842308f4 100644
--- a/lib/std/math/runtime/math_supplemental.c3
+++ b/lib/std/math/runtime/math_supplemental.c3
@@ -1,15 +1,78 @@
 module std::math::math_rt;
 
-fn float __roundevenf(float f) @extern("roundevenf") @weak @nostrip
+const double TOINT = 1 / math::DOUBLE_EPSILON;
+const float TOINTF = (float)(1 / math::FLOAT_EPSILON);
+macro force_eval_add(x, v)
 {
-	// Slow implementation
-	return math::round(f / 2) * 2;
+	$typeof(x) temp @noinit;
+	@volatile_store(temp, x + v);
 }
 
-fn double __roundeven(double d) @extern("roundeven") @weak @nostrip
+fn double __roundeven(double x) @extern("roundeven") @weak @nostrip
 {
-	// Slow implementation
-	return math::round(d / 2) * 2;
+	ulong u = bitcast(x, ulong);
+	int e = (int)((u >> 52) & 0x7ff);
+	if (e >= 0x3ff + 52) return x;
+	bool signed = u >> 63 != 0;
+	if (signed) x = -x;
+	if (e < 0x3ff - 1)
+	{
+		/* raise inexact if x!=0 */
+		force_eval_add(x, TOINT);
+		return 0 * x;
+	}
+	double y = (x + TOINT) - TOINT - x;
+	switch
+	{
+		case y > 0.5:
+			y = y + x - 1;
+		case y < -0.5:
+			y = y + x + 1;
+		case y == 0.5 || y == -0.5:
+            if (u & 1)
+            {
+                y = x + (y > 0 ? y + 1 : y - 1);
+                break;
+            }
+            nextcase;
+		default:
+			y = y + x;
+	}
+	if (signed) y = -y;
+	return y;
+}
+
+fn float __roundevenf(float x) @extern("roundevenf") @weak @nostrip
+{
+	uint u = bitcast(x, uint);
+	int e = (u >> 23) & 0xff;
+	if (e >= 0x7f + 23) return x;
+	bool signed = u >> 31 != 0;
+	if (signed) x = -x;
+	if (e < 0x7f - 1)
+	{
+		force_eval_add(x, TOINTF);
+		return 0 * x;
+	}
+	float y = (x + TOINTF) - TOINTF - x;
+	switch
+	{
+		case y > 0.5f:
+			y = y + x - 1;
+		case y < -0.5f:
+			y = y + x + 1;
+		case y == 0.5f || y == -0.5f:
+            if (u & 1)
+            {
+                y = x + (y > 0.0f ? y + 1.0f : y - 1.0f);
+                break;
+            }
+            nextcase;
+		default:
+			y = y + x;
+	}
+	if (signed) y = -y;
+	return y;
 }
 
 fn double __powidf2(double a, int b) @extern("__powidf2") @weak @nostrip
diff --git a/releasenotes.md b/releasenotes.md
index 3c8de2134..0ea3e7e3a 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -33,6 +33,8 @@
 - Added `$kindof` compile time function.
 - Deprecated `@typekind` macro in favour of `$kindof`.
 - Deprecated `@typeis` macro in favour of `$typeof(#foo) == int`.
+- `$defined(#hash)` will not check the internal expression, just that `#hash` exists.
+- Added optional macro arguments using `macro foo(int x = ...)` which can be checked using `$defined(x)`.
 
 ### Fixes
 - List.remove_at would incorrectly trigger ASAN.
@@ -104,6 +106,7 @@
 - Added `String.trim_charset`.
 - Added array `@reduce`, `@filter`, `@any`, `@all`, `@sum`, `@product`, and `@indices_of` macros.
 - `String.bformat` has reduced overhead.
+- Supplemental `roundeven` has a normal implementation.
 
 ## 0.7.4 Change list
 
diff --git a/src/compiler/llvm_codegen_expr.c b/src/compiler/llvm_codegen_expr.c
index 2c2c82197..ee40c7423 100644
--- a/src/compiler/llvm_codegen_expr.c
+++ b/src/compiler/llvm_codegen_expr.c
@@ -6218,6 +6218,7 @@ static inline void llvm_emit_macro_block(GenContext *c, BEValue *be_value, Expr
 	{
 		// Skip vararg
 		if (!val) continue;
+		if (val->var.no_init && val->var.defaulted) continue;
 		// In case we have a constant, we never do an emit. The value is already folded.
 		switch (val->var.kind)
 		{
diff --git a/src/compiler/parse_global.c b/src/compiler/parse_global.c
index 8275474ea..6d7099fdb 100644
--- a/src/compiler/parse_global.c
+++ b/src/compiler/parse_global.c
@@ -1679,7 +1679,19 @@ bool parse_parameters(ParseContext *c, Decl ***params_ref, Variadic *variadic, i
 		{
 			if (try_consume(c, TOKEN_EQ))
 			{
-				if (!parse_decl_initializer(c, param)) return poisoned_decl;
+				if (try_consume(c, TOKEN_ELLIPSIS))
+				{
+					if (parse_kind != PARAM_PARSE_MACRO)
+					{
+						PRINT_ERROR_HERE("Optional arguments with '...' is only allowed as macro arguments.");
+						return poisoned_decl;
+					}
+					param->var.no_init = true;
+				}
+				else
+				{
+					if (!parse_decl_initializer(c, param)) return poisoned_decl;
+				}
 			}
 		}
 		if (ellipsis)
diff --git a/src/compiler/sema_expr.c b/src/compiler/sema_expr.c
index 028c956a0..4fa0f30eb 100644
--- a/src/compiler/sema_expr.c
+++ b/src/compiler/sema_expr.c
@@ -1643,7 +1643,15 @@ INLINE bool sema_set_default_argument(SemaContext *context, CalledDecl *callee,
                                       bool *no_match_ref, Expr **expr_ref, bool *optional)
 {
 	Expr *init_expr = param->var.init_expr;
-	if (!init_expr) return true;
+	if (!init_expr)
+	{
+		// Handle foo = ... macro init
+		if (param->var.no_init)
+		{
+			param->var.defaulted = true;
+		}
+		return true;
+	}
 	Expr *arg = copy_expr_single(init_expr);
 	bool parameter_checked = false;
 	if (arg->resolve_status != RESOLVE_DONE)
@@ -2031,8 +2039,9 @@ SPLAT_NORMAL:;
 	{
 		if (i == vaarg_index) continue;
 		if (actual_args[i]) continue;
-		// Argument missing, that's bad.
 		Decl *param = params[i];
+		if (param->var.no_init) continue; // Macro empty args
+		// Argument missing, that's bad.
 		if (no_match_ref)
 		{
 			*no_match_ref = true;
@@ -2118,6 +2127,7 @@ NEXT_FLAG:
 		}
 		if (idx == vacount) goto TOO_FEW_ARGUMENTS;
 		expr = vaargs[idx];
+		if (!expr) goto TOO_FEW_ARGUMENTS;
 		Type *type = sema_get_va_type(context, expr, variadic);
 		if (!type_ok(type)) return false;
 
@@ -2132,6 +2142,7 @@ NEXT_FLAG:
 			c = data[i];
 			if (++idx == vacount) goto TOO_FEW_ARGUMENTS;
 			expr = vaargs[idx];
+			if (!expr) goto TOO_FEW_ARGUMENTS;
 			type = sema_get_va_type(context, expr, variadic);
 			if (!type_ok(type)) return false;
 		}
@@ -2157,6 +2168,7 @@ NEXT_FLAG:
 				c = data[i];
 				if (++idx == vacount) goto TOO_FEW_ARGUMENTS;
 				expr = vaargs[idx];
+				if (!expr) goto TOO_FEW_ARGUMENTS;
 				type = sema_get_va_type(context, expr, variadic);
 				if (!type_ok(type)) return false;
 			}
@@ -2675,6 +2687,7 @@ bool sema_expr_analyse_macro_call(SemaContext *context, Expr *call_expr, Expr *s
 			}
 		}
 		param->var.init_expr = args[i];
+		if (!args[i]) continue;
 		// Lazy arguments doesn't affect optional arg.
 		if (param->var.kind == VARDECL_PARAM_EXPR) continue;
 		has_optional_arg = has_optional_arg || IS_OPTIONAL(args[i]);
@@ -2794,6 +2807,7 @@ bool sema_expr_analyse_macro_call(SemaContext *context, Expr *call_expr, Expr *s
 	{
 		// Skip raw vararg
 		if (!param) continue;
+		if (param->var.no_init && param->var.defaulted) continue;
 		if (!sema_add_local(&macro_context, param)) goto EXIT_FAIL;
 		if (param->var.init_expr)
 		{
@@ -10345,6 +10359,13 @@ static inline bool sema_expr_analyse_ct_defined(SemaContext *context, Expr *expr
 				success = decl != NULL;
 				break;
 			}
+			case EXPR_HASH_IDENT:
+			{
+				Decl *decl = sema_find_symbol(active_context, main_expr->hash_ident_expr.identifier);
+				if (!decl_ok(decl)) goto FAIL;
+				success = decl != NULL;
+				break;
+			}
 			case EXPR_COMPILER_CONST:
 				success = sema_expr_analyse_compiler_const(active_context, main_expr, false);
 				break;
@@ -10373,13 +10394,6 @@ static inline bool sema_expr_analyse_ct_defined(SemaContext *context, Expr *expr
 				success = eval != NULL;
 				break;
 			}
-			case EXPR_HASH_IDENT:
-			{
-				Decl *decl = sema_resolve_symbol(active_context, main_expr->hash_ident_expr.identifier, NULL, main_expr->span);
-				if (!decl) goto FAIL;
-				main_expr = copy_expr_single(decl->var.init_expr);
-				goto RETRY;
-			}
 			case EXPR_SUBSCRIPT:
 			{
 				if (!sema_expr_analyse_subscript(active_context, main_expr, CHECK_VALUE, true))