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More Cleanup:

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* Name the instructions by appending to name of original
* Factor common part out of a switch statement.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21597 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Reid Spencer 2005-04-27 17:46:54 +00:00
parent e3142bee52
commit 3f7d8c65bb
1 changed files with 26 additions and 28 deletions
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54
lib/Transforms/IPO/SimplifyLibCalls.cpp
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@ -267,6 +267,7 @@ ModulePass *llvm::createSimplifyLibCallsPass()
// auto registers it into the "optlist" global above.
namespace {
// Forward declare a utility function.
bool getConstantStringLength(Value* V, uint64_t& len );
/// This LibCallOptimization will find instances of a call to "exit" that occurs
@ -366,17 +367,22 @@ public:
/// @brief Optimize the strcat library function
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
{
// Extract some information from the instruction
Module* M = ci->getParent()->getParent()->getParent();
Value* dest = ci->getOperand(1);
Value* src = ci->getOperand(2);
// Extract the initializer (while making numerous checks) from the
// source operand of the call to strcat. If we get null back, one of
// a variety of checks in get_GVInitializer failed
uint64_t len = 0;
if (!getConstantStringLength(ci->getOperand(2),len))
if (!getConstantStringLength(src,len))
return false;
// Handle the simple, do-nothing case
if (len == 0)
{
ci->replaceAllUsesWith(ci->getOperand(1));
ci->replaceAllUsesWith(dest);
ci->eraseFromParent();
return true;
}
@ -385,15 +391,13 @@ public:
// terminator as well.
len++;
// Extract some information from the instruction
Module* M = ci->getParent()->getParent()->getParent();
// We need to find the end of the destination string. That's where the
// memory is to be moved to. We just generate a call to strlen (further
// optimized in another pass). Note that the SLC.get_strlen() call
// caches the Function* for us.
CallInst* strlen_inst =
new CallInst(SLC.get_strlen(), ci->getOperand(1),"",ci);
new CallInst(SLC.get_strlen(), dest, dest->getName()+".len",ci);
// Now that we have the destination's length, we must index into the
// destination's pointer to get the actual memcpy destination (end of
@ -401,7 +405,7 @@ public:
std::vector<Value*> idx;
idx.push_back(strlen_inst);
GetElementPtrInst* gep =
new GetElementPtrInst(ci->getOperand(1),idx,"",ci);
new GetElementPtrInst(dest,idx,dest->getName()+".indexed",ci);
// We have enough information to now generate the memcpy call to
// do the concatenation for us.
@ -410,12 +414,12 @@ public:
vals.push_back(ci->getOperand(2)); // source
vals.push_back(ConstantSInt::get(Type::IntTy,len)); // length
vals.push_back(ConstantSInt::get(Type::IntTy,1)); // alignment
CallInst* memcpy_inst = new CallInst(SLC.get_memcpy(), vals, "", ci);
new CallInst(SLC.get_memcpy(), vals, "", ci);
// Finally, substitute the first operand of the strcat call for the
// strcat call itself since strcat returns its first operand; and,
// kill the strcat CallInst.
ci->replaceAllUsesWith(ci->getOperand(1));
ci->replaceAllUsesWith(dest);
ci->eraseFromParent();
return true;
}
@ -499,7 +503,7 @@ public:
vals.push_back(src); // source
vals.push_back(ConstantSInt::get(Type::IntTy,len)); // length
vals.push_back(ConstantSInt::get(Type::IntTy,1)); // alignment
CallInst* memcpy_inst = new CallInst(SLC.get_memcpy(), vals, "", ci);
new CallInst(SLC.get_memcpy(), vals, "", ci);
// Finally, substitute the first operand of the strcat call for the
// strcat call itself since strcat returns its first operand; and,
@ -586,36 +590,30 @@ public:
if (len > alignment)
return false;
// Get the type we will cast to, based on size of the string
Value* dest = ci->getOperand(1);
Value* src = ci->getOperand(2);
CastInst* SrcCast = 0;
CastInst* DestCast = 0;
Type* castType = 0;
switch (len)
{
case 0:
// The memcpy is a no-op so just dump its call.
ci->eraseFromParent();
return true;
case 1:
SrcCast = new CastInst(src,PointerType::get(Type::SByteTy),"",ci);
DestCast = new CastInst(dest,PointerType::get(Type::SByteTy),"",ci);
break;
case 2:
SrcCast = new CastInst(src,PointerType::get(Type::ShortTy),"",ci);
DestCast = new CastInst(dest,PointerType::get(Type::ShortTy),"",ci);
break;
case 4:
SrcCast = new CastInst(src,PointerType::get(Type::IntTy),"",ci);
DestCast = new CastInst(dest,PointerType::get(Type::IntTy),"",ci);
break;
case 8:
SrcCast = new CastInst(src,PointerType::get(Type::LongTy),"",ci);
DestCast = new CastInst(dest,PointerType::get(Type::LongTy),"",ci);
break;
case 1: castType = Type::SByteTy; break;
case 2: castType = Type::ShortTy; break;
case 4: castType = Type::IntTy; break;
case 8: castType = Type::LongTy; break;
default:
return false;
}
LoadInst* LI = new LoadInst(SrcCast,"",ci);
// Cast source and dest to the right sized primitive and then load/store
CastInst* SrcCast =
new CastInst(src,PointerType::get(castType),src->getName()+".cast",ci);
CastInst* DestCast =
new CastInst(dest,PointerType::get(castType),dest->getName()+".cast",ci);
LoadInst* LI = new LoadInst(SrcCast,SrcCast->getName()+".val",ci);
StoreInst* SI = new StoreInst(LI, DestCast, ci);
ci->eraseFromParent();
return true;