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Calculate and pass load sizes to the alias analysis infrastructure

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5635 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2003-02-26 19:27:35 +00:00
parent d80651df46
commit f98d8d8611
1 changed files with 19 additions and 8 deletions
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27
lib/Analysis/LoadValueNumbering.cpp
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@ -15,6 +15,7 @@
#include "llvm/Analysis/ValueNumbering.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Pass.h"
#include "llvm/iMemory.h"
#include "llvm/BasicBlock.h"
@ -72,6 +73,7 @@ void LoadVN::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<AliasAnalysis>();
AU.addRequired<ValueNumbering>();
AU.addRequired<DominatorSet>();
AU.addRequired<TargetData>();
}
// getEqualNumberNodes - Return nodes with the same value number as the
@ -81,7 +83,7 @@ void LoadVN::getEqualNumberNodes(Value *V,
std::vector<Value*> &RetVals) const {
if (LoadInst *LI = dyn_cast<LoadInst>(V)) {
// If we have a load instruction find all of the load instructions that use
// If we have a load instruction, find all of the load instructions that use
// the same source operand. We implement this recursively, because there
// could be a load of a load of a load that are all identical. We are
// guaranteed that this cannot be an infinite recursion because load
@ -147,7 +149,8 @@ void LoadVN::getEqualNumberNodes(Value *V,
// (until DestBB) contain an instruction that might invalidate Ptr.
//
static bool CheckForInvalidatingInst(BasicBlock *BB, BasicBlock *DestBB,
Value *Ptr, AliasAnalysis &AA,
Value *Ptr, unsigned Size,
AliasAnalysis &AA,
std::set<BasicBlock*> &VisitedSet) {
// Found the termination point!
if (BB == DestBB || VisitedSet.count(BB)) return false;
@ -156,12 +159,12 @@ static bool CheckForInvalidatingInst(BasicBlock *BB, BasicBlock *DestBB,
VisitedSet.insert(BB);
// Can this basic block modify Ptr?
if (AA.canBasicBlockModify(*BB, Ptr))
if (AA.canBasicBlockModify(*BB, Ptr, Size))
return true;
// Check all of our predecessor blocks...
for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI)
if (CheckForInvalidatingInst(*PI, DestBB, Ptr, AA, VisitedSet))
if (CheckForInvalidatingInst(*PI, DestBB, Ptr, Size, AA, VisitedSet))
return true;
// None of our predecessor blocks contain an invalidating instruction, and we
@ -192,6 +195,12 @@ bool LoadVN::haveEqualValueNumber(LoadInst *L1, LoadInst *L2,
BasicBlock *BB1 = L1->getParent(), *BB2 = L2->getParent();
Value *LoadAddress = L1->getOperand(0);
assert(L1->getType() == L2->getType() &&
"How could the same source pointer return different types?");
// Find out how many bytes of memory are loaded by the load instruction...
unsigned LoadSize = getAnalysis<TargetData>().getTypeSize(L1->getType());
// L1 now dominates L2. Check to see if the intervening instructions between
// the two loads include a store or call...
//
@ -199,7 +208,7 @@ bool LoadVN::haveEqualValueNumber(LoadInst *L1, LoadInst *L2,
// In this degenerate case, no checking of global basic blocks has to occur
// just check the instructions BETWEEN L1 & L2...
//
if (AA.canInstructionRangeModify(*L1, *L2, LoadAddress))
if (AA.canInstructionRangeModify(*L1, *L2, LoadAddress, LoadSize))
return false; // Cannot eliminate load
// No instructions invalidate the loads, they produce the same value!
@ -208,13 +217,14 @@ bool LoadVN::haveEqualValueNumber(LoadInst *L1, LoadInst *L2,
// Make sure that there are no store instructions between L1 and the end of
// it's basic block...
//
if (AA.canInstructionRangeModify(*L1, *BB1->getTerminator(), LoadAddress))
if (AA.canInstructionRangeModify(*L1, *BB1->getTerminator(), LoadAddress,
LoadSize))
return false; // Cannot eliminate load
// Make sure that there are no store instructions between the start of BB2
// and the second load instruction...
//
if (AA.canInstructionRangeModify(BB2->front(), *L2, LoadAddress))
if (AA.canInstructionRangeModify(BB2->front(), *L2, LoadAddress, LoadSize))
return false; // Cannot eliminate load
// Do a depth first traversal of the inverse CFG starting at L2's block,
@ -223,7 +233,8 @@ bool LoadVN::haveEqualValueNumber(LoadInst *L1, LoadInst *L2,
//
std::set<BasicBlock*> VisitedSet;
for (pred_iterator PI = pred_begin(BB2), PE = pred_end(BB2); PI != PE; ++PI)
if (CheckForInvalidatingInst(*PI, BB1, LoadAddress, AA, VisitedSet))
if (CheckForInvalidatingInst(*PI, BB1, LoadAddress, LoadSize, AA,
VisitedSet))
return false;
// If we passed all of these checks then we are sure that the two loads