[GIsel][LegalizerHelper] Account for debug insts when creating mem libcalls [5/14]
Summary:
While lowering memory intrinsics, GIsel attempts to form a tail call to
a library routine.
There might be a DBG_LABEL or something after the intrinsic call,
though: in that case, GIsel should still be able to form the tail call,
and should also delete the debug insts after the tail call as the
transform makes them invalid.
Reviewers: dsanders, aemerson
Subscribers: hiraditya, aprantl, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D78335
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index 2a9cef2..47c723c 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -462,7 +462,8 @@
/// True if an instruction is in tail position in its caller. Intended for
/// legalizing libcalls as tail calls when possible.
static bool isLibCallInTailPosition(MachineInstr &MI) {
- const Function &F = MI.getParent()->getParent()->getFunction();
+ MachineBasicBlock &MBB = *MI.getParent();
+ const Function &F = MBB.getParent()->getFunction();
// Conservatively require the attributes of the call to match those of
// the return. Ignore NoAlias and NonNull because they don't affect the
@@ -481,8 +482,8 @@
// Only tail call if the following instruction is a standard return.
auto &TII = *MI.getMF()->getSubtarget().getInstrInfo();
- MachineInstr *Next = MI.getNextNode();
- if (!Next || TII.isTailCall(*Next) || !Next->isReturn())
+ auto Next = next_nodbg(MI.getIterator(), MBB.instr_end());
+ if (Next == MBB.instr_end() || TII.isTailCall(*Next) || !Next->isReturn())
return false;
return true;
@@ -584,14 +585,16 @@
if (Info.LoweredTailCall) {
assert(Info.IsTailCall && "Lowered tail call when it wasn't a tail call?");
- // We must have a return following the call to get past
+ // We must have a return following the call (or debug insts) to get past
// isLibCallInTailPosition.
- assert(MI.getNextNode() && MI.getNextNode()->isReturn() &&
- "Expected instr following MI to be a return?");
-
- // We lowered a tail call, so the call is now the return from the block.
- // Delete the old return.
- MI.getNextNode()->eraseFromParent();
+ do {
+ MachineInstr *Next = MI.getNextNode();
+ assert(Next && (Next->isReturn() || Next->isDebugInstr()) &&
+ "Expected instr following MI to be return or debug inst?");
+ // We lowered a tail call, so the call is now the return from the block.
+ // Delete the old return.
+ Next->eraseFromParent();
+ } while (MI.getNextNode());
}
return LegalizerHelper::Legalized;
