[libcxx-commits] [libcxx] [libc++] Avoid ranges::upper_bound inside <format> (PR #173150)

[Nikolas Klauser via libcxx-commits]

https://github.com/philnik777 created https://github.com/llvm/llvm-project/pull/173150

This reduces the time to include `<vector>` from 565ms to 452ms on my machine.


>From 9fe6b9e6ca9cf9633394d41510597bb09e3150ff Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Sat, 20 Dec 2025 12:54:42 +0100
Subject: [PATCH] [libc++] Avoid ranges::upper_bound inside <format>

---
 libcxx/include/__format/extended_grapheme_cluster_table.h | 5 +++--
 libcxx/include/__format/indic_conjunct_break_table.h      | 5 +++--
 libcxx/include/__format/width_estimation_table.h          | 6 ++++--
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/libcxx/include/__format/extended_grapheme_cluster_table.h b/libcxx/include/__format/extended_grapheme_cluster_table.h
index f76e018df7ae1..6da07862d41e6 100644
--- a/libcxx/include/__format/extended_grapheme_cluster_table.h
+++ b/libcxx/include/__format/extended_grapheme_cluster_table.h
@@ -61,7 +61,7 @@
 #ifndef _LIBCPP___FORMAT_EXTENDED_GRAPHEME_CLUSTER_TABLE_H
 #define _LIBCPP___FORMAT_EXTENDED_GRAPHEME_CLUSTER_TABLE_H
 
-#include <__algorithm/ranges_upper_bound.h>
+#include <__algorithm/upper_bound.h>
 #include <__config>
 #include <__cstddef/ptrdiff_t.h>
 #include <__iterator/access.h>
@@ -1647,7 +1647,8 @@ _LIBCPP_HIDE_FROM_ABI inline constexpr uint32_t __entries[1501] = {
   // size. Then the upper bound for code point 3 will return the entry after
   // 0x1810. After moving to the previous entry the algorithm arrives at the
   // correct entry.
-  ptrdiff_t __i = std::ranges::upper_bound(__entries, (__code_point << 11) | 0x7ffu) - __entries;
+  ptrdiff_t __i =
+      std::upper_bound(std::begin(__entries), std::end(__entries), (__code_point << 11) | 0x7ffu) - __entries;
   if (__i == 0)
     return __property::__none;
 
diff --git a/libcxx/include/__format/indic_conjunct_break_table.h b/libcxx/include/__format/indic_conjunct_break_table.h
index f48ea625908e9..d85782d73286b 100644
--- a/libcxx/include/__format/indic_conjunct_break_table.h
+++ b/libcxx/include/__format/indic_conjunct_break_table.h
@@ -61,7 +61,7 @@
 #ifndef _LIBCPP___FORMAT_INDIC_CONJUNCT_BREAK_TABLE_H
 #define _LIBCPP___FORMAT_INDIC_CONJUNCT_BREAK_TABLE_H
 
-#include <__algorithm/ranges_upper_bound.h>
+#include <__algorithm/upper_bound.h>
 #include <__config>
 #include <__cstddef/ptrdiff_t.h>
 #include <__iterator/access.h>
@@ -531,7 +531,8 @@ _LIBCPP_HIDE_FROM_ABI inline constexpr uint32_t __entries[403] = {
   // size. Then the upper bound for code point 3 will return the entry after
   // 0x1810. After moving to the previous entry the algorithm arrives at the
   // correct entry.
-  ptrdiff_t __i = std::ranges::upper_bound(__entries, (__code_point << 11) | 0x7ffu) - __entries;
+  ptrdiff_t __i =
+      std::upper_bound(std::begin(__entries), std::end(__entries), (__code_point << 11) | 0x7ffu) - __entries;
   if (__i == 0)
     return __property::__none;
 
diff --git a/libcxx/include/__format/width_estimation_table.h b/libcxx/include/__format/width_estimation_table.h
index 0ea0b4f413a74..ae10a77a5b980 100644
--- a/libcxx/include/__format/width_estimation_table.h
+++ b/libcxx/include/__format/width_estimation_table.h
@@ -61,9 +61,10 @@
 #ifndef _LIBCPP___FORMAT_WIDTH_ESTIMATION_TABLE_H
 #define _LIBCPP___FORMAT_WIDTH_ESTIMATION_TABLE_H
 
-#include <__algorithm/ranges_upper_bound.h>
+#include <__algorithm/upper_bound.h>
 #include <__config>
 #include <__cstddef/ptrdiff_t.h>
+#include <__iterator/access.h>
 #include <cstdint>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -255,7 +256,8 @@ inline constexpr uint32_t __table_upper_bound = 0x0003fffd;
   if (__code_point < (__entries[0] >> 14))
     return 1;
 
-  ptrdiff_t __i = std::ranges::upper_bound(__entries, (__code_point << 14) | 0x3fffu) - __entries;
+  ptrdiff_t __i =
+      std::upper_bound(std::begin(__entries), std::end(__entries), (__code_point << 14) | 0x3fffu) - __entries;
   if (__i == 0)
     return 1;