diff options
| -rw-r--r-- | lib/Target/ARM/ARMISelLowering.cpp | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp index 8cd9aa27d7..d9bb3e65fa 100644 --- a/lib/Target/ARM/ARMISelLowering.cpp +++ b/lib/Target/ARM/ARMISelLowering.cpp @@ -1637,7 +1637,11 @@ ARMTargetLowering::IsEligibleForTailCallOptimization(SDValue Callee, return false; // FIXME: Completely disable sibcall for Thumb1 since Thumb1RegisterInfo:: - // emitEpilogue is not ready for them. + // emitEpilogue is not ready for them. Thumb tail calls also use t2B, as + // the Thumb1 16-bit unconditional branch doesn't have sufficient relocation + // support in the assembler and linker to be used. This would need to be + // fixed to fully support tail calls in Thumb1. + // // Doing this is tricky, since the LDM/POP instruction on Thumb doesn't take // LR. This means if we need to reload LR, it takes an extra instructions, // which outweighs the value of the tail call; but here we don't know yet |