[clang] [llvm] [AMDGPU] Emit a waitcnt instruction after each memory instruction (PR #79236)

[Matt Arsenault via cfe-commits]

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@@ -2326,6 +2326,20 @@ bool SIInsertWaitcnts::insertWaitcntInBlock(MachineFunction &MF,
     }
 #endif
 
+    if (ST->isPreciseMemoryEnabled() && Inst.mayLoadOrStore()) {
+      AMDGPU::Waitcnt Wait;
+      if (ST->hasExtendedWaitCounts())
+        Wait = AMDGPU::Waitcnt(0, 0, 0, 0, 0, 0, 0);
+      else
+        Wait = AMDGPU::Waitcnt(0, 0, 0, 0);
+
+      if (!Inst.mayStore())
+        Wait.StoreCnt = ~0u;
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arsenm wrote:

gfx11 doesn't have the separate load/store counters, that's gfx11. I would expect this to only use lgkmcnt here 

https://github.com/llvm/llvm-project/pull/79236