(arrow) branch main updated: GH-49424: [C++] Use std::bit_width instead of missing std::log2p1 on emscripten clang (#49425)

[kou]

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kou pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/arrow.git


The following commit(s) were added to refs/heads/main by this push:
     new 96ecb135f4 GH-49424: [C++] Use std::bit_width instead of missing 
std::log2p1 on emscripten clang (#49425)
96ecb135f4 is described below

commit 96ecb135f4d8bdb811b9eeae0ddb1583c1dd8a67
Author: Raúl Cumplido <raulcumpl...@gmail.com>
AuthorDate: Tue Mar 3 00:54:31 2026 +0100

    GH-49424: [C++] Use std::bit_width instead of missing std::log2p1 on 
emscripten clang (#49425)
    
    ### Rationale for this change
    
    The current Emscripten job fails due to macro check targeting CRAN macOS 
being used for emscripten.
    
    ### What changes are included in this PR?
    
    Avoid using workaround for Emscripten.
    
    ### Are these changes tested?
    
    Yes via CI
    
    ### Are there any user-facing changes?
    No
    
    * GitHub Issue: #49424
    
    Authored-by: Raúl Cumplido <raulcumpl...@gmail.com>
    Signed-off-by: Sutou Kouhei <k...@clear-code.com>
---
 cpp/src/arrow/util/align_util.h         | 2 +-
 cpp/src/arrow/util/bit_util.h           | 2 +-
 cpp/src/arrow/util/rle_encoding_test.cc | 2 +-
 cpp/src/parquet/chunker_internal.cc     | 2 +-
 cpp/src/parquet/encoder.cc              | 2 +-
 5 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/cpp/src/arrow/util/align_util.h b/cpp/src/arrow/util/align_util.h
index c91b047e88..a03a92cc0a 100644
--- a/cpp/src/arrow/util/align_util.h
+++ b/cpp/src/arrow/util/align_util.h
@@ -46,7 +46,7 @@ inline BitmapWordAlignParams BitmapWordAlign(const uint8_t* 
data, int64_t bit_of
                                              int64_t length) {
   // TODO: We can remove this condition once CRAN upgrades its macOS
   // SDK from 11.3.
-#if defined(__clang__) && !defined(__cpp_lib_bitops)
+#if defined(__clang__) && !defined(__cpp_lib_bitops) && 
!defined(__EMSCRIPTEN__)
   static_assert((ALIGN_IN_BYTES != 0) && ((ALIGN_IN_BYTES & (ALIGN_IN_BYTES - 
1)) == 0),
                 "ALIGN_IN_BYTES should be a positive power of two");
 #else
diff --git a/cpp/src/arrow/util/bit_util.h b/cpp/src/arrow/util/bit_util.h
index 1cbbf2042d..a6eb540fa9 100644
--- a/cpp/src/arrow/util/bit_util.h
+++ b/cpp/src/arrow/util/bit_util.h
@@ -141,7 +141,7 @@ static inline int Log2(uint64_t x) {
 
   // TODO: We can remove this condition once CRAN upgrades its macOS
   // SDK from 11.3.
-#if defined(__clang__) && !defined(__cpp_lib_bitops)
+#if defined(__clang__) && !defined(__cpp_lib_bitops) && 
!defined(__EMSCRIPTEN__)
   return std::log2p1(x - 1);
 #else
   return std::bit_width(x - 1);
diff --git a/cpp/src/arrow/util/rle_encoding_test.cc 
b/cpp/src/arrow/util/rle_encoding_test.cc
index 93405b5333..5cfa64563a 100644
--- a/cpp/src/arrow/util/rle_encoding_test.cc
+++ b/cpp/src/arrow/util/rle_encoding_test.cc
@@ -918,7 +918,7 @@ TEST(BitRle, Random) {
     }
     // TODO: We can remove this condition once CRAN upgrades its macOS
     // SDK from 11.3.
-#if defined(__clang__) && !defined(__cpp_lib_bitops)
+#if defined(__clang__) && !defined(__cpp_lib_bitops) && 
!defined(__EMSCRIPTEN__)
     if (!CheckRoundTrip(values, std::log2p1(values.size()))) {
 #else
     if (!CheckRoundTrip(values, std::bit_width(values.size()))) {
diff --git a/cpp/src/parquet/chunker_internal.cc 
b/cpp/src/parquet/chunker_internal.cc
index 097b20f0f6..1e1238e835 100644
--- a/cpp/src/parquet/chunker_internal.cc
+++ b/cpp/src/parquet/chunker_internal.cc
@@ -88,7 +88,7 @@ uint64_t CalculateMask(int64_t min_chunk_size, int64_t 
max_chunk_size, int norm_
   // by taking the floor(log2(target_size))
   // TODO: We can remove this condition once CRAN upgrades its macOS
   // SDK from 11.3.
-#if defined(__clang__) && !defined(__cpp_lib_bitops)
+#if defined(__clang__) && !defined(__cpp_lib_bitops) && 
!defined(__EMSCRIPTEN__)
   auto target_bits = std::log2p1(static_cast<uint64_t>(target_size));
 #else
   auto target_bits = std::bit_width(static_cast<uint64_t>(target_size));
diff --git a/cpp/src/parquet/encoder.cc b/cpp/src/parquet/encoder.cc
index d4ac6e1e88..1cd34947ab 100644
--- a/cpp/src/parquet/encoder.cc
+++ b/cpp/src/parquet/encoder.cc
@@ -1169,7 +1169,7 @@ void DeltaBitPackEncoder<DType>::FlushBlock() {
     // See overflow comment above.
     // TODO: We can remove this condition once CRAN upgrades its macOS
     // SDK from 11.3.
-#if defined(__clang__) && !defined(__cpp_lib_bitops)
+#if defined(__clang__) && !defined(__cpp_lib_bitops) && 
!defined(__EMSCRIPTEN__)
     const auto bit_width = bit_width_data[i] =
         std::log2p1(static_cast<UT>(max_delta) - static_cast<UT>(min_delta));
 #else