Fix the compilation assertion due to unreachable BB pruning not deleting the associat...

This patch is added to remove the unreachable MBBs reference in the jump table.

Differential Revisien: https://reviews.llvm.org/D90498
Reviewed by: amyk, bsaleil

diff --git a/llvm/include/llvm/CodeGen/MachineJumpTableInfo.h b/llvm/include/llvm/CodeGen/MachineJumpTableInfo.h
index 1178114..1d082bd 100644 (file)
--- a/llvm/include/llvm/CodeGen/MachineJumpTableInfo.h
+++ b/llvm/include/llvm/CodeGen/MachineJumpTableInfo.h
@@ -106,6 +106,9 @@ public:
     JumpTables[Idx].MBBs.clear();
   }
 
+  /// RemoveMBBFromJumpTables - If MBB is present in any jump tables, remove it.
+  bool RemoveMBBFromJumpTables(MachineBasicBlock *MBB);
+
   /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
   /// the jump tables to branch to New instead.
   bool ReplaceMBBInJumpTables(MachineBasicBlock *Old, MachineBasicBlock *New);

diff --git a/llvm/lib/CodeGen/MachineFunction.cpp b/llvm/lib/CodeGen/MachineFunction.cpp
index a7edc27..2a9a88a 100644 (file)
--- a/llvm/lib/CodeGen/MachineFunction.cpp
+++ b/llvm/lib/CodeGen/MachineFunction.cpp
@@ -420,6 +420,9 @@ MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
 void
 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
   assert(MBB->getParent() == this && "MBB parent mismatch!");
+  // Clean up any references to MBB in jump tables before deleting it.
+  if (JumpTableInfo)
+    JumpTableInfo->RemoveMBBFromJumpTables(MBB);
   MBB->~MachineBasicBlock();
   BasicBlockRecycler.Deallocate(Allocator, MBB);
 }
@@ -1047,6 +1050,17 @@ bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
   return MadeChange;
 }
 
+/// If MBB is present in any jump tables, remove it.
+bool MachineJumpTableInfo::RemoveMBBFromJumpTables(MachineBasicBlock *MBB) {
+  bool MadeChange = false;
+  for (MachineJumpTableEntry &JTE : JumpTables) {
+    auto removeBeginItr = std::remove(JTE.MBBs.begin(), JTE.MBBs.end(), MBB);
+    MadeChange |= (removeBeginItr != JTE.MBBs.end());
+    JTE.MBBs.erase(removeBeginItr, JTE.MBBs.end());
+  }
+  return MadeChange;
+}
+
 /// If Old is a target of the jump tables, update the jump table to branch to
 /// New instead.
 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,

diff --git a/llvm/test/CodeGen/PowerPC/unreachable-mbb-jtreference-elimination.ll b/llvm/test/CodeGen/PowerPC/unreachable-mbb-jtreference-elimination.ll
new file mode 100644 (file)
index 0000000..3ed0559
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/unreachable-mbb-jtreference-elimination.ll
@@ -0,0 +1,76 @@
+; RUN: llc -O2 --verify-machineinstrs -stop-before=livevars \
+; RUN:   -mtriple=powerpc64le-unknown-unknown < %s | FileCheck %s
+
+define dso_local void @foo() #0 {
+; CHECK-LABEL: fixedStack:
+; CHECK-NEXT:  stack: []
+; CHECK-NEXT:  callSites: []
+; CHECK-NEXT:  debugValueSubstitutions: []
+; CHECK-NEXT:  constants: []
+; CHECK-NEXT:  machineFunctionInfo: {}
+; CHECK-NEXT:  jumpTable:
+; CHECK-NEXT:    kind:            label-difference32
+; CHECK-NEXT:    entries:
+; CHECK-NEXT:      - id:              0
+; CHECK-NEXT:        blocks:          [  ]
+; CHECK-NEXT:  body:             |
+; CHECK-NEXT:    bb.0.entry:
+; CHECK-NEXT:      successors: %bb.1(0x80000000)
+; CHECK:           B %bb.1
+; CHECK:         bb.1.next11:
+; CHECK-NEXT:      successors: %bb.2(0x80000000)
+; CHECK:           B %bb.2
+; CHECK:         bb.2.if.end139:
+entry:
+  br label %next11
+next11:                                           ; preds = %entry
+  br i1 false, label %if.then12, label %if.end139
+if.then12:                                        ; preds = %next11
+  br label %for.cond14
+for.cond14:                                       ; preds = %if.then12
+  switch i32 undef, label %sw.epilog [
+    i32 1, label %sw.bb
+    i32 4, label %sw.bb
+    i32 6, label %sw.bb
+    i32 7, label %sw.bb
+    i32 9, label %sw.bb
+    i32 12, label %sw.bb
+    i32 15, label %sw.bb
+    i32 16, label %sw.bb
+    i32 24, label %sw.bb
+    i32 0, label %sw.bb26
+    i32 2, label %sw.bb26
+    i32 3, label %sw.bb26
+    i32 8, label %sw.bb26
+    i32 10, label %sw.bb26
+    i32 11, label %sw.bb26
+    i32 13, label %sw.bb26
+    i32 17, label %sw.bb26
+    i32 18, label %sw.bb26
+    i32 20, label %sw.bb26
+    i32 19, label %sw.bb26
+    i32 21, label %sw.bb26
+    i32 22, label %sw.bb26
+    i32 23, label %sw.bb26
+    i32 25, label %sw.bb26
+    i32 27, label %sw.bb26
+    i32 28, label %sw.bb26
+    i32 26, label %sw.bb37
+    i32 29, label %sw.bb37
+    i32 30, label %sw.bb53
+  ]
+
+sw.bb:                                            ; preds = %for.cond14
+  unreachable
+sw.bb26:                                          ; preds = %for.cond14
+  unreachable
+sw.bb37:                                          ; preds = %for.cond14
+  unreachable
+sw.bb53:                                          ; preds = %for.cond14
+  unreachable
+sw.epilog:                                        ; preds = %for.cond14
+  unreachable
+if.end139:                                        ; preds = %next11
+  unreachable
+}
+attributes #0 = { noinline optnone }