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| author | Jim Grosbach <grosbach@apple.com> | 2011-07-08 20:18:11 +0000 |
|---|---|---|
| committer | Jim Grosbach <grosbach@apple.com> | 2011-07-08 20:18:11 +0000 |
| commit | 8dc41f33f7ff668f7dd56f37bd33fbd4ed82889d (patch) | |
| tree | 0baa4f4be2137fa7ab8a69951ad9217c7451128e | |
| parent | e36e21e83097c7d1ec6704cb0d17d71336b2218e (diff) | |
Add more info to FIXME.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134729 91177308-0d34-0410-b5e6-96231b3b80d8
| -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 |