This adds support for lowering sibling calls with outgoing arguments.
define void @foo(i32 %a)
Support is ported from AArch64ISelLowering's isEligibleForTailCallOptimization. The only thing that is missing is a full port of TargetLowering::parametersInCSRMatch. So, if we're using swiftself, we'll never tail call.
- Rename analyzeCallResult to analyzeArgInfo, since the function is now used for both outgoing and incoming arguments
- Teach OutgoingArgHandler about tail calls. Tail calls use frame indices for stack arguments.
- Teach lowerFormalArguments to set the bytes in the caller's stack argument area. This is used later to check if the tail call's parameters will fit on the caller's stack.
- Add areCalleeOutgoingArgsTailCallable to perform the eligibility check on the callee's outgoing arguments.
- Update call-translator-tail-call to verify that we can now tail call with outgoing arguments, use G_FRAME_INDEX for stack arguments, and respect the size of the caller's stack
- Remove GISel-specific check lines from speculation-hardening.ll, since GISel now tail calls like the other selectors
- Add a GISel test line to tailcall-string-rvo.ll since we can tail call in that test now
- Add a GISel test line to tailcall_misched_graph.ll since we tail call there now. Add specific check lines for GISel, since the debug output from the machine-scheduler differs with GlobalISel. The dependency still holds, but the output comes out in a different order.