RyuJit: Functions with stackalloc won't inline #7109
Description
Functions using stackalloc will fail to inline with reason unknown opcode
Discovered this as part of this PR davidfowl/Channels#145 (should have probably raised it then)
Example function that will fail to inline even with aggressive inlinining
public unsafe bool TrySliceTo(byte b1, byte b2, out ReadableBuffer slice, out ReadCursor cursor)
{
byte* twoBytes = stackalloc byte[2];
twoBytes[0] = b1;
twoBytes[1] = b2;
return TrySliceTo(new Span<byte>(twoBytes, 2), out slice, out cursor);
}Changed function that will inline successfully without aggressive inlinining
public unsafe bool TrySliceTo(byte b1, byte b2, out ReadableBuffer slice, out ReadCursor cursor)
{
// use address of ushort rather than stackalloc as the inliner won't inline functions with stackalloc
ushort twoBytes;
byte* byteArray = (byte*)&twoBytes;
byteArray[0] = b1;
byteArray[1] = b2;
return TrySliceTo(new Span<byte>(byteArray, 2), out slice, out cursor);
}/cc @AndyAyersMS @JosephTremoulet
category:cq
theme:inlining
skill-level:expert
cost:medium