[llvm] [AMDGPU][GISel] Add RegBankLegalize support for G_SI_CALL (PR #165747)

[Petar Avramovic via llvm-commits]

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@@ -1059,8 +1059,21 @@ bool RegBankLegalizeHelper::lower(MachineInstr &MI,
   }
 
   if (!WaterfallSgprs.empty()) {
-    MachineBasicBlock::iterator I = MI.getIterator();
-    if (!executeInWaterfallLoop(B, make_range(I, std::next(I)), WaterfallSgprs))
+    MachineBasicBlock::iterator Start = MI.getIterator();
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petar-avramovic wrote:

I don't see the point here, move opcode specific logic to generic waterfall loop implementation, then special case G_SI_CALL opcode there

https://github.com/llvm/llvm-project/pull/165747