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Promote cases like cast (malloc sbyte, 100) to int* into

(malloc [25 x int]) directly without having to convert to
(malloc [100 x sbyte]) first.

llvm-svn: 24031
This commit is contained in:
Chris Lattner 2005-10-27 06:12:00 +00:00
parent 2b0006cd60
commit 4c9dae5fdb

View File

@ -3826,7 +3826,28 @@ Instruction *InstCombiner::PromoteCastOfAllocation(CastInst &CI,
Amt = InsertNewInstBefore(Tmp, AI);
}
} else {
return 0;
// See if we can satisfy the modulus by pulling a scale out of the array
// size argument.
unsigned ArraySizeScale = 1;
Value *NumElements = AI.getOperand(0);
if (ConstantUInt *CI = dyn_cast<ConstantUInt>(NumElements)) {
ArraySizeScale = CI->getValue();
NumElements = ConstantUInt::get(Type::UIntTy, 1);
}
// If we can now satisfy the modulus, by using a non-1 scale, we really can
// do the xform.
if ((AllocElTySize*ArraySizeScale) % CastElTySize != 0) return 0;
Amt = ConstantUInt::get(Type::UIntTy,
(AllocElTySize*ArraySizeScale)/CastElTySize);
if (ConstantUInt *CI = dyn_cast<ConstantUInt>(NumElements))
Amt = ConstantExpr::getMul(CI, cast<ConstantUInt>(Amt));
else {
Instruction *Tmp = BinaryOperator::createMul(Amt, NumElements, "tmp");
Amt = InsertNewInstBefore(Tmp, AI);
}
}
std::string Name = AI.getName(); AI.setName("");