[llvm] [AMDGPU] IGLP: Fix static variables (PR #137549)

[Matt Arsenault via llvm-commits]

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@@ -229,13 +229,13 @@ class SchedGroup {
   SchedGroup(SchedGroupMask SGMask, std::optional<unsigned> MaxSize,
              ScheduleDAGInstrs *DAG, const SIInstrInfo *TII)
       : SGMask(SGMask), MaxSize(MaxSize), DAG(DAG), TII(TII) {
-    SGID = NumSchedGroups++;
+    SGID = __atomic_fetch_add(&NumSchedGroups, 1, __ATOMIC_SEQ_CST);
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arsenm wrote:

Nothing should be atomic here 

https://github.com/llvm/llvm-project/pull/137549