[llvm] [GlobalISel][AMDGPU] Do not cache UsesAGPRs from empty functions. (PR #124799)

[Matt Arsenault via llvm-commits]

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@@ -788,6 +788,12 @@ bool SIMachineFunctionInfo::usesAGPRs(const MachineFunction &MF) const {
   if (UsesAGPRs)
     return *UsesAGPRs;
 
+  // Assume we cannot get any useful information about an empty function, but do
+  // not cache the result as we may not have useful information yet (for example
+  // after a Global-ISel fallback).
+  if (MF.empty())
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arsenm wrote:

I would hope this could not reach here 

https://github.com/llvm/llvm-project/pull/124799