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* Eliminate constant pool dependancies:

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* Eliminate DoRemoveUnusedConstants


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@453 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2001-09-07 16:42:08 +00:00
parent 9b644cc627
commit 2f11a9ded3
1 changed files with 6 additions and 29 deletions
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35
lib/Transforms/Scalar/DCE.cpp
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@ -108,31 +108,8 @@ static bool RemoveSingularPHIs(BasicBlock *BB) {
return true; // Yes, we nuked at least one phi node
}
bool opt::DoRemoveUnusedConstants(SymTabValue *S) {
bool Changed = false;
ConstantPool &CP = S->getConstantPool();
for (ConstantPool::plane_iterator PI = CP.begin(); PI != CP.end(); ++PI)
Changed |= RemoveUnusedDefs(**PI, ConstPoolDCE());
return Changed;
}
static void ReplaceUsesWithConstant(Instruction *I) {
// Get the method level constant pool
ConstantPool &CP = I->getParent()->getParent()->getConstantPool();
ConstPoolVal *CPV = 0;
ConstantPool::PlaneType *P;
if (!CP.getPlane(I->getType(), P)) { // Does plane exist?
// Yes, is it empty?
if (!P->empty()) CPV = P->front();
}
if (CPV == 0) { // We don't have an existing constant to reuse. Just add one.
CPV = ConstPoolVal::getNullConstant(I->getType()); // Create a new constant
// Add the new value to the constant pool...
CP.insert(CPV);
}
ConstPoolVal *CPV = ConstPoolVal::getNullConstant(I->getType());
// Make all users of this instruction reference the constant instead
I->replaceAllUsesWith(CPV);
@ -180,12 +157,14 @@ static void PropogatePredecessorsForPHIs(BasicBlock *BB, BasicBlock *Succ) {
// WARNING: The entry node of a method may not be simplified.
//
bool opt::SimplifyCFG(Method::iterator &BBIt) {
assert(*BBIt && (*BBIt)->getParent() && "Block not embedded in method!");
BasicBlock *BB = *BBIt;
Method *M = BB->getParent();
assert(BB && BB->getParent() && "Block not embedded in method!");
assert(BB->getTerminator() && "Degenerate basic block encountered!");
assert(BB->getParent()->front() != BB && "Can't Simplify entry block!");
// Remove basic blocks that have no predecessors... which are unreachable.
if (pred_begin(BB) == pred_end(BB) &&
!BB->hasConstantPoolReferences()) {
@ -210,7 +189,7 @@ bool opt::SimplifyCFG(Method::iterator &BBIt) {
}
delete M->getBasicBlocks().remove(BBIt);
return true;
}
}
// Check to see if this block has no instructions and only a single
// successor. If so, replace block references with successor.
@ -310,8 +289,7 @@ static bool DoDCEPass(Method *M) {
}
}
// Remove unused constants
return Changed | opt::DoRemoveUnusedConstants(M);
return Changed;
}
@ -341,6 +319,5 @@ bool opt::DoDeadCodeElimination(Module *Mod) {
}
}
while (DoRemoveUnusedConstants(Mod)) Changed = true;
return Changed;
}