[PATCH] D43566: [ARM] Fix access to stack arguments when re-aligning SP in Armv6m

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

Would it be possible to use ResolveFrameIndexReference here, like ARMBaseRegisterInfo::eliminateFrameIndex does?



================
Comment at: lib/Target/ARM/ThumbRegisterInfo.cpp:534
     // pointer or base pointer instead.
-    if (!hasBasePointer(MF)) {
+    if (isFixed) {
       FrameReg = getFrameRegister(MF);
----------------
Please add a comment explaining which objects must be referenced some particular way, and which objects you prefer to reference one way or the other for the sake of optimization.


================
Comment at: lib/Target/ARM/ThumbRegisterInfo.cpp:543
+             MF.getSubtarget().getRegisterInfo()->needsStackRealignment(MF)) {
+    FrameReg = getFrameRegister(MF);
+    Offset -= AFI->getFramePtrSpillOffset();
----------------
Please put a comment here briefly explaining why this special-case is necessary.


Repository:
  rL LLVM

https://reviews.llvm.org/D43566