6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2026-04-26 12:20:42 +00:00
Code Issues Projects Releases Wiki Activity

Skeleton for pairwise subscript testing.

Browse Source 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77437 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andreas Bolka
2009-07-29 05:35:53 +00:00
parent 45ce89ba08
commit 15f72dbf97
2 changed files with 56 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/Analysis/LoopDependenceAnalysis.cpp
+45 -3
View File
@@ -15,6 +15,8 @@
//
// TODO: adapt as implementation progresses.
//
// TODO: document lingo (pair, subscript, index)
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "lda"
@@ -24,6 +26,7 @@
#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Instructions.h"
#include "llvm/Operator.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
@@ -87,6 +90,10 @@ static AliasAnalysis::AliasResult UnderlyingObjectsAlias(AliasAnalysis *AA,
bObj, AA->getTypeStoreSize(bObj->getType()));
}
static inline const SCEV *GetZeroSCEV(ScalarEvolution *SE) {
return SE->getConstant(Type::Int32Ty, 0L);
}
//===----------------------------------------------------------------------===//
// Dependence Testing
//===----------------------------------------------------------------------===//
@@ -116,6 +123,13 @@ bool LoopDependenceAnalysis::findOrInsertDependencePair(Value *A,
return false;
}
LoopDependenceAnalysis::DependenceResult
LoopDependenceAnalysis::analyseSubscript(const SCEV *A,
const SCEV *B,
Subscript *S) const {
return Unknown; // TODO: Implement.
}
LoopDependenceAnalysis::DependenceResult
LoopDependenceAnalysis::analysePair(DependencePair *P) const {
DEBUG(errs() << "Analysing:\n" << *P->A << "\n" << *P->B << "\n");
@@ -145,9 +159,37 @@ LoopDependenceAnalysis::analysePair(DependencePair *P) const {
break; // The underlying objects alias, test accesses for dependence.
}
// We failed to analyse this pair to get a more specific answer.
DEBUG(errs() << "---> [?] cannot analyse\n");
return Unknown;
const GEPOperator *aGEP = dyn_cast<GEPOperator>(aPtr);
const GEPOperator *bGEP = dyn_cast<GEPOperator>(bPtr);
if (!aGEP || !bGEP)
return Unknown;
// FIXME: Is filtering coupled subscripts necessary?
// Analyse indices pairwise (FIXME: use GetGEPOperands from BasicAA), adding
// trailing zeroes to the smaller GEP, if needed.
GEPOperator::const_op_iterator aIdx = aGEP->idx_begin(),
aEnd = aGEP->idx_end(),
bIdx = bGEP->idx_begin(),
bEnd = bGEP->idx_end();
while (aIdx != aEnd && bIdx != bEnd) {
const SCEV* aSCEV = (aIdx != aEnd) ? SE->getSCEV(*aIdx) : GetZeroSCEV(SE);
const SCEV* bSCEV = (bIdx != bEnd) ? SE->getSCEV(*bIdx) : GetZeroSCEV(SE);
Subscript subscript;
DependenceResult result = analyseSubscript(aSCEV, bSCEV, &subscript);
if (result != Dependent) {
// We either proved independence or failed to analyse this subscript.
// Further subscripts will not improve the situation, so abort early.
return result;
}
P->Subscripts.push_back(subscript);
if (aIdx != aEnd) ++aIdx;
if (bIdx != bEnd) ++bIdx;
}
// Either there were no subscripts or all subscripts were analysed to be
// dependent; in both cases we know the accesses are dependent.
return Dependent;
}
bool LoopDependenceAnalysis::depends(Value *A, Value *B) {