[PATCH] D84042: [AArch64][SVE] Don't align the last SVE callee save.

[Sander de Smalen via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG26b4ef369497: [AArch64][SVE] Don't align the last SVE callee save. (authored by sdesmalen).

Changed prior to commit:
  https://reviews.llvm.org/D84042?vs=280495&id=281233#toc

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D84042/new/

https://reviews.llvm.org/D84042

Files:
  llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
  llvm/test/CodeGen/AArch64/framelayout-sve.mir
  llvm/test/CodeGen/AArch64/sve-trunc.ll


Index: llvm/test/CodeGen/AArch64/sve-trunc.ll
===================================================================
--- llvm/test/CodeGen/AArch64/sve-trunc.ll
+++ llvm/test/CodeGen/AArch64/sve-trunc.ll
@@ -117,7 +117,7 @@
 ; CHECK-NEXT:    addvl sp, sp, #-1
 ; CHECK-NEXT:    str p4, [sp, #7, mul vl] // 2-byte Folded Spill
 ; CHECK-NEXT:    .cfi_def_cfa_offset 16
-; CHECK-NEXT:    .cfi_offset p4, -16
+; CHECK-NEXT:    .cfi_offset p4, -2
 ; CHECK-NEXT:    .cfi_offset w29, -16
 ; CHECK-NEXT:    ptrue p0.d
 ; CHECK-NEXT:    and z7.d, z7.d, #0x1
Index: llvm/test/CodeGen/AArch64/framelayout-sve.mir
===================================================================
--- llvm/test/CodeGen/AArch64/framelayout-sve.mir
+++ llvm/test/CodeGen/AArch64/framelayout-sve.mir
@@ -573,7 +573,7 @@
 # CHECK-NEXT:       stack-id: sve-vec, callee-saved-register: '$z23',
 # CHECK:        - { id: 8, name: '', type: spill-slot, offset: -34, size: 2, alignment: 2,
 # CHECK-NEXT:       stack-id: sve-vec, callee-saved-register: '$p4',
-# CHECK:        - { id: 9, name: '', type: spill-slot, offset: -48, size: 2, alignment: 16,
+# CHECK:        - { id: 9, name: '', type: spill-slot, offset: -36, size: 2, alignment: 2,
 # CHECK-NEXT:       stack-id: sve-vec, callee-saved-register: '$p15',
 # CHECK:        - { id: 10, name: '', type: spill-slot, offset: -16, size: 8, alignment: 16,
 # CHECK-NEXT:       stack-id: default, callee-saved-register: '$fp',
Index: llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
+++ llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
@@ -1192,7 +1192,7 @@
 
   // Process the SVE callee-saves to determine what space needs to be
   // allocated.
-  if (AFI->getSVECalleeSavedStackSize()) {
+  if (int64_t CalleeSavedSize = AFI->getSVECalleeSavedStackSize()) {
     // Find callee save instructions in frame.
     CalleeSavesBegin = MBBI;
     assert(IsSVECalleeSave(CalleeSavesBegin) && "Unexpected instruction");
@@ -1200,11 +1200,7 @@
       ++MBBI;
     CalleeSavesEnd = MBBI;
 
-    int64_t OffsetToFirstCalleeSaveFromSP =
-        MFI.getObjectOffset(AFI->getMaxSVECSFrameIndex());
-    StackOffset OffsetToCalleeSavesFromSP =
-        StackOffset(OffsetToFirstCalleeSaveFromSP, MVT::nxv1i8) + SVEStackSize;
-    AllocateBefore -= OffsetToCalleeSavesFromSP;
+    AllocateBefore = {CalleeSavedSize, MVT::nxv1i8};
     AllocateAfter = SVEStackSize - AllocateBefore;
   }
 
@@ -1582,7 +1578,7 @@
   // deallocated.
   StackOffset DeallocateBefore = {}, DeallocateAfter = SVEStackSize;
   MachineBasicBlock::iterator RestoreBegin = LastPopI, RestoreEnd = LastPopI;
-  if (AFI->getSVECalleeSavedStackSize()) {
+  if (int64_t CalleeSavedSize = AFI->getSVECalleeSavedStackSize()) {
     RestoreBegin = std::prev(RestoreEnd);;
     while (IsSVECalleeSave(RestoreBegin) &&
            RestoreBegin != MBB.begin())
@@ -1592,12 +1588,9 @@
     assert(IsSVECalleeSave(RestoreBegin) &&
            IsSVECalleeSave(std::prev(RestoreEnd)) && "Unexpected instruction");
 
-    int64_t OffsetToFirstCalleeSaveFromSP =
-        MFI.getObjectOffset(AFI->getMaxSVECSFrameIndex());
-    StackOffset OffsetToCalleeSavesFromSP =
-        StackOffset(OffsetToFirstCalleeSaveFromSP, MVT::nxv1i8) + SVEStackSize;
-    DeallocateBefore = OffsetToCalleeSavesFromSP;
-    DeallocateAfter = SVEStackSize - DeallocateBefore;
+    StackOffset CalleeSavedSizeAsOffset = {CalleeSavedSize, MVT::nxv1i8};
+    DeallocateBefore = SVEStackSize - CalleeSavedSizeAsOffset;
+    DeallocateAfter = CalleeSavedSizeAsOffset;
   }
 
   // Deallocate the SVE area.
@@ -2612,9 +2605,6 @@
 
   // Then process all callee saved slots.
   if (getSVECalleeSaveSlotRange(MFI, MinCSFrameIndex, MaxCSFrameIndex)) {
-    // Make sure to align the last callee save slot.
-    MFI.setObjectAlignment(MaxCSFrameIndex, Align(16));
-
     // Assign offsets to the callee save slots.
     for (int I = MinCSFrameIndex; I <= MaxCSFrameIndex; ++I) {
       Offset += MFI.getObjectSize(I);
@@ -2624,6 +2614,9 @@
     }
   }
 
+  // Ensure that the Callee-save area is aligned to 16bytes.
+  Offset = alignTo(Offset, Align(16U));
+
   // Create a buffer of SVE objects to allocate and sort it.
   SmallVector<int, 8> ObjectsToAllocate;
   for (int I = 0, E = MFI.getObjectIndexEnd(); I != E; ++I) {


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