[PATCH] D46777: [ARM] Back up R4 and LR if calling the stack probe function

[Martin Storsjö via Phabricator via llvm-commits]

mstorsjo added inline comments.


================
Comment at: lib/Target/ARM/ARMFrameLowering.cpp:1624
+    unsigned SpillEstimate = SavedRegs.count();
+    unsigned StackEstimate = MFI.estimateStackSize(MF) + 4 * SpillEstimate + 16;
+
----------------
efriedma wrote:
> Where does this StackEstimate come from?  Could it be factored out into a helper?
Hmm, unsure how feasible it is... But after looking closer, it seems we don't really need all of it; `MFI.estimateStackSize(MF)` should in itself be the value needed (or an overestimate of it).


Repository:
  rL LLVM

https://reviews.llvm.org/D46777