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authorEric Christopher <echristo@apple.com>2008-06-26 01:19:35 +0000
committerEric Christopher <echristo@apple.com>2008-06-26 01:19:35 +0000
commit872a738775ea3a78136da9914a9bbbb56326cacc (patch)
treed1c36a392c0f89ef1044f48731b63bfa9a20cd22 /lib/Transforms/Scalar
parent0d2b0aba424bd3959bb5c807873def8f53e57a3c (diff)
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Remove unused function.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52749 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms/Scalar')
-rw-r--r--lib/Transforms/Scalar/SimplifyLibCalls.cpp83
1 files changed, 1 insertions, 82 deletions
diff --git a/lib/Transforms/Scalar/SimplifyLibCalls.cpp b/lib/Transforms/Scalar/SimplifyLibCalls.cpp
index 79ec3d941f..6bc6ad407f 100644
--- a/lib/Transforms/Scalar/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Scalar/SimplifyLibCalls.cpp
@@ -23,6 +23,7 @@
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/Support/IRBuilder.h"
+#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Target/TargetData.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/StringMap.h"
@@ -229,88 +230,6 @@ void LibCallOptimization::EmitFWrite(Value *Ptr, Value *Size, Value *File,
// Helper Functions
//===----------------------------------------------------------------------===//
-/// GetConstantStringInfo - This function computes the length of a
-/// null-terminated C string pointed to by V. If successful, it returns true
-/// and returns the string in Str. If unsuccessful, it returns false.
-static bool GetConstantStringInfo(Value *V, std::string &Str) {
- // Look bitcast instructions.
- if (BitCastInst *BCI = dyn_cast<BitCastInst>(V))
- return GetConstantStringInfo(BCI->getOperand(0), Str);
-
- // If the value is not a GEP instruction nor a constant expression with a
- // GEP instruction, then return false because ConstantArray can't occur
- // any other way
- User *GEP = 0;
- if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(V)) {
- GEP = GEPI;
- } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
- if (CE->getOpcode() != Instruction::GetElementPtr)
- return false;
- GEP = CE;
- } else {
- return false;
- }
-
- // Make sure the GEP has exactly three arguments.
- if (GEP->getNumOperands() != 3)
- return false;
-
- // Check to make sure that the first operand of the GEP is an integer and
- // has value 0 so that we are sure we're indexing into the initializer.
- if (ConstantInt *Idx = dyn_cast<ConstantInt>(GEP->getOperand(1))) {
- if (!Idx->isZero())
- return false;
- } else
- return false;
-
- // If the second index isn't a ConstantInt, then this is a variable index
- // into the array. If this occurs, we can't say anything meaningful about
- // the string.
- uint64_t StartIdx = 0;
- if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
- StartIdx = CI->getZExtValue();
- else
- return false;
-
- // The GEP instruction, constant or instruction, must reference a global
- // variable that is a constant and is initialized. The referenced constant
- // initializer is the array that we'll use for optimization.
- GlobalVariable* GV = dyn_cast<GlobalVariable>(GEP->getOperand(0));
- if (!GV || !GV->isConstant() || !GV->hasInitializer())
- return false;
- Constant *GlobalInit = GV->getInitializer();
-
- // Handle the ConstantAggregateZero case
- if (isa<ConstantAggregateZero>(GlobalInit)) {
- // This is a degenerate case. The initializer is constant zero so the
- // length of the string must be zero.
- Str.clear();
- return true;
- }
-
- // Must be a Constant Array
- ConstantArray *Array = dyn_cast<ConstantArray>(GlobalInit);
- if (Array == 0 || Array->getType()->getElementType() != Type::Int8Ty)
- return false;
-
- // Get the number of elements in the array
- uint64_t NumElts = Array->getType()->getNumElements();
-
- // Traverse the constant array from StartIdx (derived above) which is
- // the place the GEP refers to in the array.
- for (unsigned i = StartIdx; i < NumElts; ++i) {
- Constant *Elt = Array->getOperand(i);
- ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
- if (!CI) // This array isn't suitable, non-int initializer.
- return false;
- if (CI->isZero())
- return true; // we found end of string, success!
- Str += (char)CI->getZExtValue();
- }
-
- return false; // The array isn't null terminated.
-}
-
/// GetStringLengthH - If we can compute the length of the string pointed to by
/// the specified pointer, return 'len+1'. If we can't, return 0.
static uint64_t GetStringLengthH(Value *V, SmallPtrSet<PHINode*, 32> &PHIs) {