[llvm-commits] [llvm] r149111 - /llvm/trunk/lib/CodeGen/MachineFunction.cpp
Chris Lattner
sabre at nondot.org
Thu Jan 26 17:46:01 PST 2012
Author: lattner
Date: Thu Jan 26 19:46:00 2012
New Revision: 149111
URL: http://llvm.org/viewvc/llvm-project?rev=149111&view=rev
Log:
Rewrite CanShareConstantPoolEntry to be implemented in terms of the
mid-level constant folding APIs instead of doing its own analysis.
This makes it more general (e.g. can now share a <2 x i64> with a
<4 x i32>) and avoid duplicating a bunch of logic.
Modified:
llvm/trunk/lib/CodeGen/MachineFunction.cpp
Modified: llvm/trunk/lib/CodeGen/MachineFunction.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineFunction.cpp?rev=149111&r1=149110&r2=149111&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineFunction.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineFunction.cpp Thu Jan 26 19:46:00 2012
@@ -27,6 +27,7 @@
#include "llvm/CodeGen/Passes.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
+#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/DebugInfo.h"
#include "llvm/Support/Debug.h"
#include "llvm/Target/TargetData.h"
@@ -654,38 +655,37 @@
// reject them.
if (A->getType() == B->getType()) return false;
+ // We can't handle structs or arrays.
+ if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
+ isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
+ return false;
+
// For now, only support constants with the same size.
uint64_t StoreSize = TD->getTypeStoreSize(A->getType());
if (StoreSize != TD->getTypeStoreSize(B->getType()) ||
StoreSize > 128)
return false;
-
- // If a floating-point value and an integer value have the same encoding,
- // they can share a constant-pool entry.
- if (const ConstantFP *AFP = dyn_cast<ConstantFP>(A))
- if (const ConstantInt *BI = dyn_cast<ConstantInt>(B))
- return AFP->getValueAPF().bitcastToAPInt() == BI->getValue();
- if (const ConstantFP *BFP = dyn_cast<ConstantFP>(B))
- if (const ConstantInt *AI = dyn_cast<ConstantInt>(A))
- return BFP->getValueAPF().bitcastToAPInt() == AI->getValue();
-
- // Two vectors can share an entry if each pair of corresponding
- // elements could.
- if (const ConstantVector *AV = dyn_cast<ConstantVector>(A))
- if (const ConstantVector *BV = dyn_cast<ConstantVector>(B)) {
- if (AV->getType()->getNumElements() != BV->getType()->getNumElements())
- return false;
- for (unsigned i = 0, e = AV->getType()->getNumElements(); i != e; ++i)
- if (!CanShareConstantPoolEntry(AV->getOperand(i),
- BV->getOperand(i), TD))
- return false;
- return true;
- }
+ Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
- // TODO: Handle other cases.
-
- return false;
+ // Try constant folding a bitcast of both instructions to an integer. If we
+ // get two identical ConstantInt's, then we are good to share them. We use
+ // the constant folding APIs to do this so that we get the benefit of
+ // TargetData.
+ if (isa<PointerType>(A->getType()))
+ A = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
+ const_cast<Constant*>(A), TD);
+ else if (A->getType() != IntTy)
+ A = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
+ const_cast<Constant*>(A), TD);
+ if (isa<PointerType>(B->getType()))
+ B = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
+ const_cast<Constant*>(B), TD);
+ else if (B->getType() != IntTy)
+ B = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
+ const_cast<Constant*>(B), TD);
+
+ return A == B;
}
/// getConstantPoolIndex - Create a new entry in the constant pool or return
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