[llvm] [AMDGPU] Fixed crash due to virtual register defs not dominating uses (PR #198472)

[Matt Arsenault via llvm-commits]

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@@ -44,6 +45,12 @@ using namespace llvm;
 DEBUG_COUNTER(RewriteAGPRCopyMFMACounter, DEBUG_TYPE,
               "Controls which MFMA chains are rewritten to AGPR form");
 
+static cl::opt<unsigned> ImplicitDefScanLimit(
+    "amdgpu-mfma-vgpr-to-agpr-spill-scan-limit", cl::Hidden, cl::init(4),
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arsenm wrote:

As a general rule do not add cl::opts 

https://github.com/llvm/llvm-project/pull/198472