[llvm] [AMDGPU] Do not count implicit VGPRs in SIInsertWaitcnts (PR #109049)

Stanislav Mekhanoshin via llvm-commits llvm-commits at lists.llvm.org
Fri Sep 20 01:58:47 PDT 2024


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@@ -1752,6 +1752,15 @@ bool SIInsertWaitcnts::generateWaitcntInstBefore(MachineInstr &MI,
         const bool IsVGPR = TRI->isVectorRegister(*MRI, Op.getReg());
         for (int RegNo = Interval.first; RegNo < Interval.second; ++RegNo) {
           if (IsVGPR) {
+            // Implicit VGPR defs and uses are never a part of the memory
+            // instructions description and usually present to account for
+            // super-register liveness. Tied implicit sources on loads though
+            // are real uses.
+            // TODO: Most of the other instructions also have implicit uses
+            // for the liveness accounting only.
+            if (Op.isImplicit() && MI.mayLoadOrStore() && !Op.isTied())
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rampitec wrote:

Just did it, removed the check for tied operand.

https://github.com/llvm/llvm-project/pull/109049


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