[llvm] [docs] Fix default Sphinx worker count (PR #217429)

[Reid Kleckner via llvm-commits]

https://github.com/rnk created https://github.com/llvm/llvm-project/pull/217429

I renamed the variable at the last minute, and the search and replace didn't catch all instances. Follow-up to #217161 / 0e6f9b26868c37cfb27fdc99af0524ed78e1dfd8.

>From 07ce2a8a89bcce10a509980fd7cf7e28c38e36a2 Mon Sep 17 00:00:00 2001
From: Reid Kleckner <rkleckner at nvidia.com>
Date: Wed, 19 Aug 2026 18:33:46 +0000
Subject: [PATCH] [docs] Fix default Sphinx worker count

The rename from LLVM_SPHINX_BUILD_JOBS to LLVM_SPHINX_THREADS left the cache initialization reading the old variable name. That overwrote the computed default with an empty value, so the sphinx-build -j flag was omitted unless LLVM_SPHINX_THREADS was set explicitly.

Use the computed LLVM_SPHINX_THREADS value when creating the cache entry.
---
 llvm/cmake/modules/AddSphinxTarget.cmake | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/cmake/modules/AddSphinxTarget.cmake b/llvm/cmake/modules/AddSphinxTarget.cmake
index 6b3987cbbc7c0..197a1552d6b4e 100644
--- a/llvm/cmake/modules/AddSphinxTarget.cmake
+++ b/llvm/cmake/modules/AddSphinxTarget.cmake
@@ -163,7 +163,7 @@ function (add_sphinx_target builder project)
     math(EXPR LLVM_SPHINX_THREADS
          "(${number_of_logical_cores} + 1) / 2")
   endif()
-  set(LLVM_SPHINX_THREADS "${LLVM_SPHINX_BUILD_JOBS}"
+  set(LLVM_SPHINX_THREADS "${LLVM_SPHINX_THREADS}"
       CACHE STRING "Define the number of parallel jobs for each Sphinx build.")
   if (LLVM_SPHINX_THREADS)
     set(sphinx_jobs_flag -j ${LLVM_SPHINX_THREADS})