ARM: Creating a vector from a lane of another.
The VDUP instruction source register doesn't allow a non-constant lane
index, so make sure we don't construct a ARM::VDUPLANE node asking it to
do so.
rdar://13328063
http://llvm.org/bugs/show_bug.cgi?id=13963
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176413 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index 5d24e92..514971f 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -4452,8 +4452,11 @@
// If we are VDUPing a value that comes directly from a vector, that will
// cause an unnecessary move to and from a GPR, where instead we could
- // just use VDUPLANE.
- if (Value->getOpcode() == ISD::EXTRACT_VECTOR_ELT) {
+ // just use VDUPLANE. We can only do this if the lane being extracted
+ // is at a constant index, as the VDUP from lane instructions only have
+ // constant-index forms.
+ if (Value->getOpcode() == ISD::EXTRACT_VECTOR_ELT &&
+ isa<ConstantSDNode>(Value->getOperand(1))) {
// We need to create a new undef vector to use for the VDUPLANE if the
// size of the vector from which we get the value is different than the
// size of the vector that we need to create. We will insert the element