Change min/max runtime behaviour to match IEEE 754-2019

src/llvm_backend_utility.cpp

@@ -124,11 +124,29 @@ gb_internal lbValue lb_emit_select(lbProcedure *p, lbValue cond, lbValue x, lbVa
 gb_internal lbValue lb_emit_min(lbProcedure *p, Type *t, lbValue x, lbValue y) {
 	x = lb_emit_conv(p, x, t);
 	y = lb_emit_conv(p, y, t);
+	if (is_type_float(t)) {
+		// NOTE(bill): f either operand is a NaN, returns NaN. Otherwise returns the lesser of the two arguments.
+		// -0.0 is considered to be less than +0.0 for this intrinsic.
+		// These semantics are specified by IEEE 754-2019.
+		LLVMValueRef args[2] = {x.value, y.value};
+		LLVMTypeRef types[1] = {lb_type(p->module, t)};
+		LLVMValueRef v = lb_call_intrinsic(p, "llvm.minimum", args, gb_count_of(args), types, gb_count_of(types));
+		return {v, t};
+	}
 	return lb_emit_select(p, lb_emit_comp(p, Token_Lt, x, y), x, y);
 }
 gb_internal lbValue lb_emit_max(lbProcedure *p, Type *t, lbValue x, lbValue y) {
 	x = lb_emit_conv(p, x, t);
 	y = lb_emit_conv(p, y, t);
+	if (is_type_float(t)) {
+		// NOTE(bill): If either operand is a NaN, returns NaN. Otherwise returns the greater of the two arguments.
+		// -0.0 is considered to be less than +0.0 for this intrinsic.
+		// These semantics are specified by IEEE 754-2019.
+		LLVMValueRef args[2] = {x.value, y.value};
+		LLVMTypeRef types[1] = {lb_type(p->module, t)};
+		LLVMValueRef v = lb_call_intrinsic(p, "llvm.maximum", args, gb_count_of(args), types, gb_count_of(types));
+		return {v, t};
+	}
 	return lb_emit_select(p, lb_emit_comp(p, Token_Gt, x, y), x, y);
 }