6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-12-13 20:32:21 +00:00
Code Issues Projects Releases Wiki Activity

Make InstCombineCasts.cpp:OptimizeIntToFloatBitCast endian safe.

Browse Source 
The OptimizeIntToFloatBitCast converts shift-truncate sequences
into extractelement operations.  The computation of the element
index to be used in the resulting operation is currently only
correct for little-endian targets.

This commit fixes the element index computation to be correct
for big-endian targets as well.  If the target byte order is
unknown, the optimization cannot be performed at all.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178031 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Ulrich Weigand 2013-03-26 15:36:14 +00:00
parent a8c8c45838
commit fdc6177490
1 changed files with 9 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
lib/Transforms/InstCombine/InstCombineCasts.cpp
View File

@ -1610,6 +1610,9 @@ static Value *OptimizeIntegerToVectorInsertions(BitCastInst &CI,
/// OptimizeIntToFloatBitCast - See if we can optimize an integer->float/double
/// bitcast. The various long double bitcasts can't get in here.
static Instruction *OptimizeIntToFloatBitCast(BitCastInst &CI,InstCombiner &IC){
// We need to know the target byte order to perform this optimization.
if (!IC.getDataLayout()) return 0;
Value *Src = CI.getOperand(0);
Type *DestTy = CI.getType();
@ -1631,7 +1634,10 @@ static Instruction *OptimizeIntToFloatBitCast(BitCastInst &CI,InstCombiner &IC){
VecInput = IC.Builder->CreateBitCast(VecInput, VecTy);
}
return ExtractElementInst::Create(VecInput, IC.Builder->getInt32(0));
unsigned Elt = 0;
if (IC.getDataLayout()->isBigEndian())
Elt = VecTy->getPrimitiveSizeInBits() / DestWidth - 1;
return ExtractElementInst::Create(VecInput, IC.Builder->getInt32(Elt));
}
}
@ -1653,6 +1659,8 @@ static Instruction *OptimizeIntToFloatBitCast(BitCastInst &CI,InstCombiner &IC){
}
unsigned Elt = ShAmt->getZExtValue() / DestWidth;
if (IC.getDataLayout()->isBigEndian())
Elt = VecTy->getPrimitiveSizeInBits() / DestWidth - 1 - Elt;
return ExtractElementInst::Create(VecInput, IC.Builder->getInt32(Elt));
}
}