CalledValuePropagation.cpp File Reference

#include "llvm/Transforms/IPO/CalledValuePropagation.h"
#include "llvm/Analysis/SparsePropagation.h"
#include "llvm/Analysis/ValueLatticeUtils.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Transforms/IPO.h"

Go to the source code of this file.

Classes
struct	llvm::LatticeKeyInfo< CVPLatticeKey >
	A specialization of LatticeKeyInfo for CVPLatticeKeys. More...

Namespaces
namespace	llvm
	This is an optimization pass for GlobalISel generic memory operations.

Macros
#define	DEBUG_TYPE   "called-value-propagation"

Functions
static bool	runCVP (Module &M)

Variables
static cl::opt< unsigned >	MaxFunctionsPerValue ("cvp-max-functions-per-value", cl::Hidden, cl::init(4), cl::desc("The maximum number of functions to track per lattice value"))
	The maximum number of functions to track per lattice value.

Macro Definition Documentation

DEBUG_TYPE

#define DEBUG_TYPE   "called-value-propagation"

Definition at line 30 of file CalledValuePropagation.cpp.

Function Documentation

runCVP()

bool runCVP ( Module & M )

static

Definition at line 375 of file CalledValuePropagation.cpp.

References llvm::CallingConv::C, llvm::canTrackArgumentsInterprocedurally(), Changed, llvm::MDBuilder::createCallees(), F, llvm::SparseSolver< LatticeKey, LatticeVal, KeyInfo >::getExistingValueState(), llvm::SparseSolver< LatticeKey, LatticeVal, KeyInfo >::MarkBlockExecutable(), and llvm::SparseSolver< LatticeKey, LatticeVal, KeyInfo >::Solve().

Referenced by llvm::CalledValuePropagationPass::run().

Variable Documentation

MaxFunctionsPerValue

cl::opt< unsigned > MaxFunctionsPerValue("cvp-max-functions-per-value", cl::Hidden, cl::init(4), cl::desc("The maximum number of functions to track per lattice value")) ( "cvp-max-functions-per-value" , cl::Hidden , cl::init(4) , cl::desc("The maximum number of functions to track per lattice value")  )

static

The maximum number of functions to track per lattice value.

Once the number of functions a call site can possibly target exceeds this threshold, it's lattice value becomes overdefined. The number of possible lattice values is bounded by Ch(F, M), where F is the number of functions in the module and M is MaxFunctionsPerValue. As such, this value should be kept very small. We likely can't do anything useful for call sites with a large number of possible targets, anyway.