Temporarily disable on-demand fast-isel.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107393 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());
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 073e296..94f0efc 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -709,11 +709,13 @@
FastIS->startNewBlock(BB);
// Do FastISel on as many instructions as possible.
for (; BI != End; ++BI) {
+#if 0
// Defer instructions with no side effects; they'll be emitted
// on-demand later.
if (BI->isSafeToSpeculativelyExecute() &&
!FuncInfo->isExportedInst(BI))
continue;
+#endif
// Try to select the instruction with FastISel.
if (FastIS->SelectInstruction(BI))