optimize "integer extraction out of the middle of a vector" as produced
by SRoA. This is part of rdar://7892780, but needs another xform to
expose this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112232 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/InstCombine/InstCombineCasts.cpp b/lib/Transforms/InstCombine/InstCombineCasts.cpp
index ef5bbc4..82c3591 100644
--- a/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -1337,31 +1337,53 @@
/// 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) {
+static Instruction *OptimizeIntToFloatBitCast(BitCastInst &CI,InstCombiner &IC){
Value *Src = CI.getOperand(0);
+ const Type *DestTy = CI.getType();
// If this is a bitcast from int to float, check to see if the int is an
// extraction from a vector.
Value *VecInput = 0;
+ // bitcast(trunc(bitcast(somevector)))
if (match(Src, m_Trunc(m_BitCast(m_Value(VecInput)))) &&
isa<VectorType>(VecInput->getType())) {
const VectorType *VecTy = cast<VectorType>(VecInput->getType());
- const Type *DestTy = CI.getType();
+ unsigned DestWidth = DestTy->getPrimitiveSizeInBits();
+
+ if (VecTy->getPrimitiveSizeInBits() % DestWidth == 0) {
+ // If the element type of the vector doesn't match the result type,
+ // bitcast it to be a vector type we can extract from.
+ if (VecTy->getElementType() != DestTy) {
+ VecTy = VectorType::get(DestTy,
+ VecTy->getPrimitiveSizeInBits() / DestWidth);
+ VecInput = IC.Builder->CreateBitCast(VecInput, VecTy);
+ }
- // If the element type of the vector doesn't match the result type, but the
- // vector type's size is a multiple of the result type, bitcast it to be a
- // vector type we can extract from.
- if (VecTy->getElementType() != DestTy &&
- VecTy->getPrimitiveSizeInBits() % DestTy->getPrimitiveSizeInBits()==0) {
- VecTy = VectorType::get(DestTy,
- VecTy->getPrimitiveSizeInBits() / DestTy->getPrimitiveSizeInBits());
- VecInput = IC.Builder->CreateBitCast(VecInput, VecTy);
- }
-
- if (VecTy->getElementType() == DestTy)
return ExtractElementInst::Create(VecInput, IC.Builder->getInt32(0));
+ }
}
+ // bitcast(trunc(lshr(bitcast(somevector), cst))
+ ConstantInt *ShAmt = 0;
+ if (match(Src, m_Trunc(m_LShr(m_BitCast(m_Value(VecInput)),
+ m_ConstantInt(ShAmt)))) &&
+ isa<VectorType>(VecInput->getType())) {
+ const VectorType *VecTy = cast<VectorType>(VecInput->getType());
+ unsigned DestWidth = DestTy->getPrimitiveSizeInBits();
+ if (VecTy->getPrimitiveSizeInBits() % DestWidth == 0 &&
+ ShAmt->getZExtValue() % DestWidth == 0) {
+ // If the element type of the vector doesn't match the result type,
+ // bitcast it to be a vector type we can extract from.
+ if (VecTy->getElementType() != DestTy) {
+ VecTy = VectorType::get(DestTy,
+ VecTy->getPrimitiveSizeInBits() / DestWidth);
+ VecInput = IC.Builder->CreateBitCast(VecInput, VecTy);
+ }
+
+ unsigned Elt = ShAmt->getZExtValue() / DestWidth;
+ return ExtractElementInst::Create(VecInput, IC.Builder->getInt32(Elt));
+ }
+ }
return 0;
}