[llvm] [AMDGPU] Graph-based Module Splitting Rewrite (PR #104763)

[Siu Chi Chan via llvm-commits]

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@@ -251,23 +216,30 @@ calculateFunctionCosts(SplitModuleLogger &SML, GetTTIFn GetTTI, Module &M,
     assert((ModuleCost + FnCost) >= ModuleCost && "Overflow!");
     ModuleCost += FnCost;
 
-    if (isEntryPoint(&Fn))
+    if (AMDGPU::isEntryFunctionCC(Fn.getCallingConv()))
       KernelCost += FnCost;
   }
 
-  CostType FnCost = (ModuleCost - KernelCost);
-  CostType ModuleCostOr1 = ModuleCost ? ModuleCost : 1;
-  SML << "=> Total Module Cost: " << ModuleCost << '\n'
-      << "  => KernelCost: " << KernelCost << " ("
-      << format("%0.2f", (float(KernelCost) / ModuleCostOr1) * 100) << "%)\n"
-      << "  => FnsCost: " << FnCost << " ("
-      << format("%0.2f", (float(FnCost) / ModuleCostOr1) * 100) << "%)\n";
+  if (CostMap.empty())
+    return 0;
+
+  assert(ModuleCost);
+  LLVM_DEBUG({
+    const CostType FnCost = ModuleCost - KernelCost;
+    dbgs() << " - total module cost is " << ModuleCost << ". kernels cost "
+           << "" << KernelCost << " ("
+           << format("%0.2f", (float(KernelCost) / ModuleCost) * 100)
+           << "% of the module), functions cost " << FnCost << " ("
+           << format("%0.2f", (float(FnCost) / ModuleCost) * 100)
+           << "% of the module)\n";
+  });
 
   return ModuleCost;
 }
 
+/// \return true if \p F can be indirectly called
 static bool canBeIndirectlyCalled(const Function &F) {
-  if (F.isDeclaration() || isEntryPoint(&F))
+  if (F.isDeclaration() || AMDGPU::isEntryFunctionCC(F.getCallingConv()))
     return false;
   return !F.hasLocalLinkage() ||
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scchan wrote:

Given this is an AMDGPU module and that the module should be standalone/closed-world, we should have visibility of all the callers.  The only externally reachable functions are the kernel functions so we can probably assume non-kernel functions without address taken can't be indirectly called?  

https://github.com/llvm/llvm-project/pull/104763