diff --git a/library/core/src/fmt/builders.rs b/library/core/src/fmt/builders.rs
index ceec98c8659fb..9ed1f451dc572 100644
--- a/library/core/src/fmt/builders.rs
+++ b/library/core/src/fmt/builders.rs
@@ -155,7 +155,7 @@ impl<'a, 'b: 'a> DebugStruct<'a, 'b> {
     #[stable(feature = "debug_builders", since = "1.2.0")]
     pub fn field(&mut self, name: &str, value: &dyn fmt::Debug) -> &mut Self {
         self.result = self.result.and_then(|_| {
-            if self.is_pretty() {
+            if crate::hint::unlikely(self.is_pretty()) {
                 if !self.has_fields {
                     self.fmt.write_str(" {\n")?;
                 }
@@ -352,7 +352,7 @@ impl<'a, 'b: 'a> DebugTuple<'a, 'b> {
     #[stable(feature = "debug_builders", since = "1.2.0")]
     pub fn field(&mut self, value: &dyn fmt::Debug) -> &mut Self {
         self.result = self.result.and_then(|_| {
-            if self.is_pretty() {
+            if crate::hint::unlikely(self.is_pretty()) {
                 if self.fields == 0 {
                     self.fmt.write_str("(\n")?;
                 }
@@ -479,7 +479,7 @@ struct DebugInner<'a, 'b: 'a> {
 impl<'a, 'b: 'a> DebugInner<'a, 'b> {
     fn entry(&mut self, entry: &dyn fmt::Debug) {
         self.result = self.result.and_then(|_| {
-            if self.is_pretty() {
+            if crate::hint::unlikely(self.is_pretty()) {
                 if !self.has_fields {
                     self.fmt.write_str("\n")?;
                 }
@@ -1004,7 +1004,7 @@ impl<'a, 'b: 'a> DebugMap<'a, 'b> {
                                     without completing the previous one"
             );
 
-            if self.is_pretty() {
+            if crate::hint::unlikely(self.is_pretty()) {
                 if !self.has_fields {
                     self.fmt.write_str("\n")?;
                 }
@@ -1076,7 +1076,7 @@ impl<'a, 'b: 'a> DebugMap<'a, 'b> {
         self.result = self.result.and_then(|_| {
             assert!(self.has_key, "attempted to format a map value before its key");
 
-            if self.is_pretty() {
+            if crate::hint::unlikely(self.is_pretty()) {
                 let mut slot = None;
                 let mut writer = PadAdapter::wrap(self.fmt, &mut slot, &mut self.state);
                 value.fmt(&mut writer)?;