Add an experimental option to run gep-splitting and no-load GVN
just before codegen.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89439 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LLVMTargetMachine.cpp b/lib/CodeGen/LLVMTargetMachine.cpp
index 0db459b..8800f22 100644
--- a/lib/CodeGen/LLVMTargetMachine.cpp
+++ b/lib/CodeGen/LLVMTargetMachine.cpp
@@ -66,6 +66,11 @@
EnableFastISelOption("fast-isel", cl::Hidden,
cl::desc("Enable the \"fast\" instruction selector"));
+// Enable or disable an experimental optimization to split GEPs
+// and run a special GVN pass which does not examine loads, in
+// an effort to factor out redundancy implicit in complex GEPs.
+static cl::opt<bool> EnableSplitGEPGVN("split-gep-gvn", cl::Hidden,
+ cl::desc("Split GEPs and run no-load GVN"));
LLVMTargetMachine::LLVMTargetMachine(const Target &T,
const std::string &TargetTriple)
@@ -223,6 +228,12 @@
CodeGenOpt::Level OptLevel) {
// Standard LLVM-Level Passes.
+ // Optionally, tun split-GEPs and no-load GVN.
+ if (EnableSplitGEPGVN) {
+ PM.add(createGEPSplitterPass());
+ PM.add(createGVNPass(/*NoPRE=*/false, /*NoLoads=*/true));
+ }
+
// Run loop strength reduction before anything else.
if (OptLevel != CodeGenOpt::None && !DisableLSR) {
PM.add(createLoopStrengthReducePass(getTargetLowering()));