[llvm] [AIX][PowerPC] Teach the Threading Library About the Number of Physical Cores on AIX (PR #67683)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-support

<details>
<summary>Changes</summary>

The threading library does not recognize AIX and always returns -1 for number of physical cores. This PR teaches the library to recognize AIX and obtain the correct value for the number of physical cores. 

---
Full diff: https://github.com/llvm/llvm-project/pull/67683.diff


2 Files Affected:

- (modified) llvm/lib/Support/Unix/Threading.inc (+6) 
- (modified) llvm/unittests/Support/Threading.cpp (+1-1) 


``````````diff
diff --git a/llvm/lib/Support/Unix/Threading.inc b/llvm/lib/Support/Unix/Threading.inc
index 819748db4ec21e8..1d5f01264784d4e 100644
--- a/llvm/lib/Support/Unix/Threading.inc
+++ b/llvm/lib/Support/Unix/Threading.inc
@@ -55,6 +55,10 @@
 #include <unistd.h>      // For syscall()
 #endif
 
+#if defined(_AIX)
+#include <sys/systemcfg.h>
+#endif
+
 namespace llvm {
 pthread_t
 llvm_execute_on_thread_impl(void *(*ThreadFunc)(void *), void *Arg,
@@ -432,6 +436,8 @@ static int computeHostNumPhysicalCores() {
       static_cast<uintptr_t>(reinterpret_cast<unsigned int &>(CVT[CVTCSD])));
   return reinterpret_cast<int &>(CSD[CSD_NUMBER_ONLINE_STANDARD_CPS]);
 }
+#elif defined(_AIX)
+static int computeHostNumPhysicalCores() { return _system_configuration.ncpus; }
 #else
 // On other systems, return -1 to indicate unknown.
 static int computeHostNumPhysicalCores() { return -1; }
diff --git a/llvm/unittests/Support/Threading.cpp b/llvm/unittests/Support/Threading.cpp
index b5eff6f6f14fba6..7fd8b1cfe3a5b9c 100644
--- a/llvm/unittests/Support/Threading.cpp
+++ b/llvm/unittests/Support/Threading.cpp
@@ -29,7 +29,7 @@ static bool isThreadingSupportedArchAndOS() {
   return (Host.isOSWindows() && llvm_is_multithreaded()) || Host.isOSDarwin() ||
          (Host.isX86() && Host.isOSLinux()) ||
          (Host.isOSLinux() && !Host.isAndroid()) ||
-         (Host.isSystemZ() && Host.isOSzOS());
+         (Host.isSystemZ() && Host.isOSzOS()) || Host.isOSAIX();
 #else
   return false;
 #endif

``````````

</details>


https://github.com/llvm/llvm-project/pull/67683