Alternative, where we dont add a verifier pass after fallback instead

Author: davemgreen

llvm/lib/CodeGen/TargetPassConfig.cpp

@@ -1039,11 +1039,13 @@ bool TargetPassConfig::addCoreISelPasses() {
 
     if (addGlobalInstructionSelect())
       return true;
+  }
 
-    // Pass to reset the MachineFunction if the ISel failed.
+  // Pass to reset the MachineFunction if the ISel failed. Outside of the above
+  // if so that the verifier is not added to it.
+  if (Selector == SelectorType::GlobalISel)
     addPass(createResetMachineFunctionPass(
         reportDiagnosticWhenGlobalISelFallback(), isGlobalISelAbortEnabled()));
-  }
 
   // Run the SDAG InstSelector, providing a fallback path when we do not want to
   // abort on not-yet-supported input.

llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.cpp

@@ -788,12 +788,6 @@ 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())
-    return false;
-
   if (!mayNeedAGPRs()) {
     UsesAGPRs = false;
     return false;