[AArch64][GlobalISel] Always fall back on tail calls with -tailcallopt
-tailcallopt requires that we perform different stack adjustments than with
sibling calls. For example, the `@caller_to0_from8` function in
test/CodeGen/AArch64/tail-call.ll requires that we adjust SP. Without
-tailcallopt, this adjustment does not happen. With it, however, it is expected.
So, to ensure that adding sibling call support doesn't break -tailcallopt,
make CallLowering always fall back on possible tail calls when -tailcallopt
is passed in.
Update test/CodeGen/AArch64/tail-call.ll with a GlobalISel line to make sure
that we don't differ from the SDAG implementation at any point.
Differential Revision: https://reviews.llvm.org/D67245
llvm-svn: 371227
diff --git a/llvm/lib/Target/AArch64/AArch64CallLowering.cpp b/llvm/lib/Target/AArch64/AArch64CallLowering.cpp
index e97b329..ffca0e7 100644
--- a/llvm/lib/Target/AArch64/AArch64CallLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64CallLowering.cpp
@@ -567,6 +567,12 @@
return false;
}
+ if (Info.IsTailCall && MF.getTarget().Options.GuaranteedTailCallOpt) {
+ // TODO: Until we lower all tail calls, we should fall back on this.
+ LLVM_DEBUG(dbgs() << "Cannot handle -tailcallopt yet.\n");
+ return false;
+ }
+
SmallVector<ArgInfo, 8> SplitArgs;
for (auto &OrigArg : Info.OrigArgs) {
splitToValueTypes(OrigArg, SplitArgs, DL, MRI, Info.CallConv);