Add 'musttail' marker to call instructions
This is similar to the 'tail' marker, except that it guarantees that
tail call optimization will occur. It also comes with convervative IR
verification rules that ensure that tail call optimization is possible.
Reviewers: nicholas
Differential Revision: http://llvm-reviews.chandlerc.com/D3240
llvm-svn: 207143
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 0c0ce5a..fce7d2f 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -3720,6 +3720,10 @@
isTailCall = IsEligibleForTailCallOptimization(Callee, CallConv, isVarArg,
Ins, DAG);
+ if (!isTailCall && CLI.CS && CLI.CS->isMustTailCall())
+ report_fatal_error("failed to perform tail call elimination on a call "
+ "site marked musttail");
+
if (PPCSubTarget.isSVR4ABI()) {
if (PPCSubTarget.isPPC64())
return LowerCall_64SVR4(Chain, Callee, CallConv, isVarArg,