[llvm] [MachineScheduler] Add support for scheduling while in SSA (PR #161054)

[Matt Arsenault via llvm-commits]

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@@ -526,6 +526,11 @@ static cl::opt<bool> HasClosedWorldAssumption(
     cl::desc("Whether has closed-world assumption at link time"),
     cl::init(false), cl::Hidden);
 
+static cl::opt<bool>
+    UseSSAMachineScheduler("amdgpu-use-ssa-machine-scheduler",
+                           cl::desc("Use the machine scheduler in SSA mode."),
+                           cl::init(false), cl::Hidden);
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arsenm wrote:

Can you fix this to have one general flag that works instead of making every target override a virtual and add its own flag? This is a really stupid pattern that keeps repeating

https://github.com/llvm/llvm-project/pull/161054