--- Reverse-merging r107947 into '.':
U utils/TableGen/FastISelEmitter.cpp
--- Reverse-merging r107943 into '.':
U test/CodeGen/X86/fast-isel.ll
U test/CodeGen/X86/fast-isel-loads.ll
U include/llvm/Target/TargetLowering.h
U include/llvm/Support/PassNameParser.h
U include/llvm/CodeGen/FunctionLoweringInfo.h
U include/llvm/CodeGen/CallingConvLower.h
U include/llvm/CodeGen/FastISel.h
U include/llvm/CodeGen/SelectionDAGISel.h
U lib/CodeGen/LLVMTargetMachine.cpp
U lib/CodeGen/CallingConvLower.cpp
U lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
U lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
U lib/CodeGen/SelectionDAG/FastISel.cpp
U lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
U lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
U lib/CodeGen/SelectionDAG/InstrEmitter.cpp
U lib/CodeGen/SelectionDAG/TargetLowering.cpp
U lib/Target/XCore/XCoreISelLowering.cpp
U lib/Target/XCore/XCoreISelLowering.h
U lib/Target/X86/X86ISelLowering.cpp
U lib/Target/X86/X86FastISel.cpp
U lib/Target/X86/X86ISelLowering.h
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107987 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LLVMTargetMachine.cpp b/lib/CodeGen/LLVMTargetMachine.cpp
index bf3137e..d437370 100644
--- a/lib/CodeGen/LLVMTargetMachine.cpp
+++ b/lib/CodeGen/LLVMTargetMachine.cpp
@@ -329,15 +329,19 @@
if (OptLevel != CodeGenOpt::None)
PM.add(createOptimizePHIsPass());
- if (OptLevel != CodeGenOpt::None) {
- // With optimization, dead code should already be eliminated. However
- // there is one known exception: lowered code for arguments that are only
- // used by tail calls, where the tail calls reuse the incoming stack
- // arguments directly (see t11 in test/CodeGen/X86/sibcall.ll).
- PM.add(createDeadMachineInstructionElimPass());
- printAndVerify(PM, "After codegen DCE pass",
- /* allowDoubleDefs= */ true);
+ // Delete dead machine instructions regardless of optimization level.
+ //
+ // At -O0, fast-isel frequently creates dead instructions.
+ //
+ // With optimization, dead code should already be eliminated. However
+ // there is one known exception: lowered code for arguments that are only
+ // used by tail calls, where the tail calls reuse the incoming stack
+ // arguments directly (see t11 in test/CodeGen/X86/sibcall.ll).
+ PM.add(createDeadMachineInstructionElimPass());
+ printAndVerify(PM, "After codegen DCE pass",
+ /* allowDoubleDefs= */ true);
+ if (OptLevel != CodeGenOpt::None) {
PM.add(createOptimizeExtsPass());
if (!DisableMachineLICM)
PM.add(createMachineLICMPass());