[PATCH] D130488: AMDGPU: Fix assertion when printing unreachable functions

[Matt Arsenault via Phabricator via llvm-commits]

arsenm updated this revision to Diff 447459.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D130488/new/

https://reviews.llvm.org/D130488

Files:
  llvm/lib/Target/AMDGPU/AMDGPUResourceUsageAnalysis.cpp
  llvm/test/CodeGen/AMDGPU/resource-usage-dead-function.ll


Index: llvm/test/CodeGen/AMDGPU/resource-usage-dead-function.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AMDGPU/resource-usage-dead-function.ll
@@ -0,0 +1,34 @@
+; RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 -o - %s | FileCheck -check-prefix=GCN %s
+
+; Make sure there's no assertion when trying to report the resource
+; usage for a function which becomes dead during codegen.
+
+ at gv.fptr0 = external hidden unnamed_addr addrspace(4) constant void()*, align 4
+
+; GCN-LABEL: unreachable:
+; Function info:
+; codeLenInByte = 4
+define internal fastcc void @unreachable() {
+  %fptr = load void()*, void()* addrspace(4)* @gv.fptr0
+  call void %fptr()
+  unreachable
+}
+
+
+; GCN-LABEL: entry:
+; GCN-NOT: s_swappc_b64
+; GCN: s_endpgm
+
+; GCN: .amdhsa_private_segment_fixed_size 0
+; GCN: .amdhsa_uses_dynamic_stack 0
+define amdgpu_kernel void @entry() {
+bb0:
+  br i1 false, label %bb1, label %bb2
+
+bb1:
+  tail call fastcc void @unreachable()
+  unreachable
+
+bb2:
+  ret void
+}
Index: llvm/lib/Target/AMDGPU/AMDGPUResourceUsageAnalysis.cpp
===================================================================
--- llvm/lib/Target/AMDGPU/AMDGPUResourceUsageAnalysis.cpp
+++ llvm/lib/Target/AMDGPU/AMDGPUResourceUsageAnalysis.cpp
@@ -125,6 +125,26 @@
     HasIndirectCall |= Info.HasIndirectCall;
   }
 
+  // It's possible we have unreachable functions in the module which weren't
+  // visited by the PO traversal. Make sure we have some resource counts to
+  // report.
+  for (const auto &IT : CG) {
+    const Function *F = IT.first;
+    if (!F || F->isDeclaration())
+      continue;
+
+    auto CI = CallGraphResourceInfo.insert(
+      std::make_pair(F, SIFunctionResourceInfo()));
+    if (!CI.second) // Skip already visited functions
+      continue;
+
+    SIFunctionResourceInfo &Info = CI.first->second;
+    MachineFunction *MF = MMI.getMachineFunction(*F);
+    assert(MF && "function must have been generated already");
+    Info = analyzeResourceUsage(*MF, TM);
+    HasIndirectCall |= Info.HasIndirectCall;
+  }
+
   if (HasIndirectCall)
     propagateIndirectCallRegisterUsage();
 


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