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fix a bug Anders ran into where scalarrepl would crash when promoting

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a union containing a vector and an array whose elements were smaller than
the vector elements.  this means we need to compile the load of the 
array elements into an extract element plus a truncate.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47752 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-02-29 07:12:06 +00:00
parent 800de31776
commit 9d34c4d678
2 changed files with 84 additions and 57 deletions
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125
lib/Transforms/Scalar/ScalarReplAggregates.cpp
View File

@ -1154,70 +1154,81 @@ Value *SROA::ConvertUsesOfLoadToScalar(LoadInst *LI, AllocaInst *NewAI,
// We win, no conversion needed.
return NV;
}
// If the result type of the 'union' is a pointer, then this must be ptr->ptr
// cast. Anything else would result in NV being an integer.
if (isa<PointerType>(NV->getType())) {
assert(isa<PointerType>(LI->getType()));
return new BitCastInst(NV, LI->getType(), LI->getName(), LI);
}
if (const VectorType *PTy = dyn_cast<VectorType>(NV->getType())) {
if (const VectorType *VTy = dyn_cast<VectorType>(NV->getType())) {
// If the result alloca is a vector type, this is either an element
// access or a bitcast to another vector type.
if (isa<VectorType>(LI->getType())) {
NV = new BitCastInst(NV, LI->getType(), LI->getName(), LI);
} else {
// Must be an element access.
const TargetData &TD = getAnalysis<TargetData>();
unsigned Elt = Offset/TD.getABITypeSizeInBits(PTy->getElementType());
NV = new ExtractElementInst(NV, ConstantInt::get(Type::Int32Ty, Elt),
"tmp", LI);
if (isa<VectorType>(LI->getType()))
return new BitCastInst(NV, LI->getType(), LI->getName(), LI);
// Otherwise it must be an element access.
const TargetData &TD = getAnalysis<TargetData>();
unsigned Elt = 0;
if (Offset) {
unsigned EltSize = TD.getABITypeSizeInBits(VTy->getElementType());
Elt = Offset/EltSize;
Offset -= EltSize*Elt;
}
} else if (isa<PointerType>(NV->getType())) {
assert(isa<PointerType>(LI->getType()));
// Must be ptr->ptr cast. Anything else would result in NV being
// an integer.
NV = new ExtractElementInst(NV, ConstantInt::get(Type::Int32Ty, Elt),
"tmp", LI);
// If we're done, return this element.
if (NV->getType() == LI->getType() && Offset == 0)
return NV;
}
const IntegerType *NTy = cast<IntegerType>(NV->getType());
// If this is a big-endian system and the load is narrower than the
// full alloca type, we need to do a shift to get the right bits.
int ShAmt = 0;
const TargetData &TD = getAnalysis<TargetData>();
if (TD.isBigEndian()) {
// On big-endian machines, the lowest bit is stored at the bit offset
// from the pointer given by getTypeStoreSizeInBits. This matters for
// integers with a bitwidth that is not a multiple of 8.
ShAmt = TD.getTypeStoreSizeInBits(NTy) -
TD.getTypeStoreSizeInBits(LI->getType()) - Offset;
} else {
ShAmt = Offset;
}
// Note: we support negative bitwidths (with shl) which are not defined.
// We do this to support (f.e.) loads off the end of a structure where
// only some bits are used.
if (ShAmt > 0 && (unsigned)ShAmt < NTy->getBitWidth())
NV = BinaryOperator::createLShr(NV,
ConstantInt::get(NV->getType(),ShAmt),
LI->getName(), LI);
else if (ShAmt < 0 && (unsigned)-ShAmt < NTy->getBitWidth())
NV = BinaryOperator::createShl(NV,
ConstantInt::get(NV->getType(),-ShAmt),
LI->getName(), LI);
// Finally, unconditionally truncate the integer to the right width.
unsigned LIBitWidth = TD.getTypeSizeInBits(LI->getType());
if (LIBitWidth < NTy->getBitWidth())
NV = new TruncInst(NV, IntegerType::get(LIBitWidth),
LI->getName(), LI);
// If the result is an integer, this is a trunc or bitcast.
if (isa<IntegerType>(LI->getType())) {
// Should be done.
} else if (LI->getType()->isFloatingPoint()) {
// Just do a bitcast, we know the sizes match up.
NV = new BitCastInst(NV, LI->getType(), LI->getName(), LI);
} else {
const IntegerType *NTy = cast<IntegerType>(NV->getType());
// If this is a big-endian system and the load is narrower than the
// full alloca type, we need to do a shift to get the right bits.
int ShAmt = 0;
const TargetData &TD = getAnalysis<TargetData>();
if (TD.isBigEndian()) {
// On big-endian machines, the lowest bit is stored at the bit offset
// from the pointer given by getTypeStoreSizeInBits. This matters for
// integers with a bitwidth that is not a multiple of 8.
ShAmt = TD.getTypeStoreSizeInBits(NTy) -
TD.getTypeStoreSizeInBits(LI->getType()) - Offset;
} else {
ShAmt = Offset;
}
// Note: we support negative bitwidths (with shl) which are not defined.
// We do this to support (f.e.) loads off the end of a structure where
// only some bits are used.
if (ShAmt > 0 && (unsigned)ShAmt < NTy->getBitWidth())
NV = BinaryOperator::createLShr(NV,
ConstantInt::get(NV->getType(),ShAmt),
LI->getName(), LI);
else if (ShAmt < 0 && (unsigned)-ShAmt < NTy->getBitWidth())
NV = BinaryOperator::createShl(NV,
ConstantInt::get(NV->getType(),-ShAmt),
LI->getName(), LI);
// Finally, unconditionally truncate the integer to the right width.
unsigned LIBitWidth = TD.getTypeSizeInBits(LI->getType());
if (LIBitWidth < NTy->getBitWidth())
NV = new TruncInst(NV, IntegerType::get(LIBitWidth),
LI->getName(), LI);
// If the result is an integer, this is a trunc or bitcast.
if (isa<IntegerType>(LI->getType())) {
assert(NV->getType() == LI->getType() && "Truncate wasn't enough?");
} else if (LI->getType()->isFloatingPoint()) {
// Just do a bitcast, we know the sizes match up.
NV = new BitCastInst(NV, LI->getType(), LI->getName(), LI);
} else {
// Otherwise must be a pointer.
NV = new IntToPtrInst(NV, LI->getType(), LI->getName(), LI);
}
// Otherwise must be a pointer.
NV = new IntToPtrInst(NV, LI->getType(), LI->getName(), LI);
}
assert(NV->getType() == LI->getType() && "Didn't convert right?");
return NV;
}

16
test/Transforms/ScalarRepl/2008-02-28-SubElementExtractCrash.ll Normal file
View File

@ -0,0 +1,16 @@
; RUN: llvm-as < %s | opt -scalarrepl | llvm-dis | not grep alloca
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
target triple = "i686-apple-darwin8"
%struct..0anon = type { <1 x i64> }
define i32 @main(i32 %argc, i8** %argv) {
entry:
%c = alloca %struct..0anon ; <%struct..0anon*> [#uses=2]
%tmp2 = getelementptr %struct..0anon* %c, i32 0, i32 0 ; <<1 x i64>*> [#uses=1]
store <1 x i64> zeroinitializer, <1 x i64>* %tmp2, align 8
%tmp7 = getelementptr %struct..0anon* %c, i32 0, i32 0 ; <<1 x i64>*> [#uses=1]
%tmp78 = bitcast <1 x i64>* %tmp7 to [2 x i32]* ; <[2 x i32]*> [#uses=1]
%tmp9 = getelementptr [2 x i32]* %tmp78, i32 0, i32 0 ; <i32*> [#uses=1]
%tmp10 = load i32* %tmp9, align 4 ; <i32> [#uses=0]
unreachable
}