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Constant fold vector bitcasts of halves similarly to how floats and doubles are folded. Test case included. 

llvm-svn: 176131
This commit is contained in:
Michael Ilseman 2013-02-26 22:51:07 +00:00
parent fd666e9e3c
commit a7b93c1e5f
2 changed files with 13 additions and 6 deletions
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14
llvm/lib/Analysis/ConstantFolding.cpp
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@ -54,13 +54,12 @@ static Constant *FoldBitCast(Constant *C, Type *DestTy,
// Handle a vector->integer cast.
if (IntegerType *IT = dyn_cast<IntegerType>(DestTy)) {
ConstantDataVector *CDV = dyn_cast<ConstantDataVector>(C);
if (CDV == 0)
VectorType *VTy = dyn_cast<VectorType>(C->getType());
if (VTy == 0)
return ConstantExpr::getBitCast(C, DestTy);
unsigned NumSrcElts = CDV->getType()->getNumElements();
Type *SrcEltTy = CDV->getType()->getElementType();
unsigned NumSrcElts = VTy->getNumElements();
Type *SrcEltTy = VTy->getElementType();
// If the vector is a vector of floating point, convert it to vector of int
// to simplify things.
@ -70,9 +69,12 @@ static Constant *FoldBitCast(Constant *C, Type *DestTy,
VectorType::get(IntegerType::get(C->getContext(), FPWidth), NumSrcElts);
// Ask IR to do the conversion now that #elts line up.
C = ConstantExpr::getBitCast(C, SrcIVTy);
CDV = cast<ConstantDataVector>(C);
}
ConstantDataVector *CDV = dyn_cast<ConstantDataVector>(C);
if (CDV == 0)
return ConstantExpr::getBitCast(C, DestTy);
// Now that we know that the input value is a vector of integers, just shift
// and insert them into our result.
unsigned BitShift = TD.getTypeAllocSizeInBits(SrcEltTy);

5
llvm/test/Transforms/InstCombine/bitcast-vector-fold.ll
View File

@ -31,3 +31,8 @@ define <4 x i32> @test6() {
%tmp3 = bitcast <2 x double> <double 0.5, double 1.0> to <4 x i32>
ret <4 x i32> %tmp3
}
define i32 @test7() {
%tmp3 = bitcast <2 x half> <half 0xH1100, half 0xH0011> to i32
ret i32 %tmp3
}