[llvm] [Parallel] Ensure getThreadIndex()==0 for sequential tasks (PR #109084)

[Alexey Lapshin via llvm-commits]

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@@ -217,13 +194,18 @@ TaskGroup::~TaskGroup() {
 void TaskGroup::spawn(std::function<void()> F, bool Sequential) {
 #if LLVM_ENABLE_THREADS
   if (Parallel) {
+    if (Sequential) {
+      // Act as worker thread 0.
+      threadIndex = 0;
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avl-llvm wrote:

I see, thanks. So removing Sequential mode and including the for... loop in the task at the call site in elf::scanRelocations would OK, then.

https://github.com/llvm/llvm-project/pull/109084