Add a new pass for doing late hoisting of floating-point and vector
constants out of loops. These aren't covered by the regular LICM
pass, because in LLVM IR constants don't require separate
instructions. They're not always covered by the MachineLICM pass
either, because it doesn't know how to unfold folded constant-pool
loads. This is somewhat experimental at this point, and off by
default.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82076 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LLVMTargetMachine.cpp b/lib/CodeGen/LLVMTargetMachine.cpp
index 5b6cfdc..94c6fa6 100644
--- a/lib/CodeGen/LLVMTargetMachine.cpp
+++ b/lib/CodeGen/LLVMTargetMachine.cpp
@@ -39,6 +39,8 @@
cl::desc("Dump emitter generated instructions as assembly"));
static cl::opt<bool> PrintGCInfo("print-gc", cl::Hidden,
cl::desc("Dump garbage collector data"));
+static cl::opt<bool> HoistConstants("hoist-constants", cl::Hidden,
+ cl::desc("Hoist constants out of loops"));
static cl::opt<bool> VerifyMachineCode("verify-machineinstrs", cl::Hidden,
cl::desc("Verify generated machine code"),
cl::init(getenv("LLVM_VERIFY_MACHINEINSTRS")!=NULL));
@@ -259,8 +261,11 @@
// Make sure that no unreachable blocks are instruction selected.
PM.add(createUnreachableBlockEliminationPass());
- if (OptLevel != CodeGenOpt::None)
+ if (OptLevel != CodeGenOpt::None) {
+ if (HoistConstants)
+ PM.add(createCodeGenLICMPass());
PM.add(createCodeGenPreparePass(getTargetLowering()));
+ }
PM.add(createStackProtectorPass(getTargetLowering()));