Add a flag to disable the ARM64DeadRegisterDefinitionsPass
This patch adds a -arm64-dead-def-elimination flag so that it is possible to
disable dead definition elimination. Includes test case.
llvm-svn: 206207
diff --git a/llvm/lib/Target/ARM64/ARM64TargetMachine.cpp b/llvm/lib/Target/ARM64/ARM64TargetMachine.cpp
index 101dc25..f4a7996 100644
--- a/llvm/lib/Target/ARM64/ARM64TargetMachine.cpp
+++ b/llvm/lib/Target/ARM64/ARM64TargetMachine.cpp
@@ -39,6 +39,14 @@
" optimization hints (LOH)"),
cl::init(true));
+static cl::opt<bool>
+EnableDeadRegisterElimination("arm64-dead-def-elimination", cl::Hidden,
+ cl::desc("Enable the pass that removes dead"
+ " definitons and replaces stores to"
+ " them with stores to the zero"
+ " register"),
+ cl::init(true));
+
extern "C" void LLVMInitializeARM64Target() {
// Register the target.
RegisterTargetMachine<ARM64TargetMachine> X(TheARM64Target);
@@ -135,7 +143,8 @@
bool ARM64PassConfig::addPostRegAlloc() {
// Change dead register definitions to refer to the zero register.
- addPass(createARM64DeadRegisterDefinitions());
+ if (EnableDeadRegisterElimination)
+ addPass(createARM64DeadRegisterDefinitions());
return true;
}