[PATCH] D124615: [AArch64][SVE] Restore SP from FP when SVE CSRs and variable sized objects are present

[Bradley Smith via Phabricator via llvm-commits]

bsmith updated this revision to Diff 426057.
bsmith retitled this revision from "[AArch64][SVE] Restore SP from base pointer when it and SVE frame are present" to "[AArch64][SVE] Restore SP from FP when SVE CSRs and variable sized objects are present".
bsmith edited the summary of this revision.
bsmith added a comment.

- Rework patch to use same mechanism as stack reaignment, rather than using base pointer.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D124615/new/

https://reviews.llvm.org/D124615

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


Index: llvm/test/CodeGen/AArch64/sve-alloca.ll
===================================================================
--- llvm/test/CodeGen/AArch64/sve-alloca.ll
+++ llvm/test/CodeGen/AArch64/sve-alloca.ll
@@ -66,6 +66,7 @@
 ; CHECK-NEXT:    st1d { z1.d }, p0, [x0, #1, mul vl]
 ; CHECK-NEXT:    st1d { z0.d }, p0, [x0]
 ; CHECK-NEXT:    bl bar
+; CHECK-NEXT:    addvl sp, x29, #-18
 ; CHECK-NEXT:    ldr p15, [sp, #4, mul vl] // 2-byte Folded Reload
 ; CHECK-NEXT:    ldr p14, [sp, #5, mul vl] // 2-byte Folded Reload
 ; CHECK-NEXT:    ldr p13, [sp, #6, mul vl] // 2-byte Folded Reload
@@ -94,7 +95,6 @@
 ; CHECK-NEXT:    ldr z10, [sp, #15, mul vl] // 16-byte Folded Reload
 ; CHECK-NEXT:    ldr z9, [sp, #16, mul vl] // 16-byte Folded Reload
 ; CHECK-NEXT:    ldr z8, [sp, #17, mul vl] // 16-byte Folded Reload
-; CHECK-NEXT:    addvl sp, sp, #18
 ; CHECK-NEXT:    mov sp, x29
 ; CHECK-NEXT:    ldp x28, x19, [sp, #16] // 16-byte Folded Reload
 ; CHECK-NEXT:    ldp x29, x30, [sp], #32 // 16-byte Folded Reload
Index: llvm/test/CodeGen/AArch64/framelayout-sve.mir
===================================================================
--- llvm/test/CodeGen/AArch64/framelayout-sve.mir
+++ llvm/test/CodeGen/AArch64/framelayout-sve.mir
@@ -629,7 +629,6 @@
 # CHECK-NEXT: $sp = frame-setup SUBXri $sp, 16, 0
 # CHECK-NEXT: $x19 = ADDXri $sp, 0, 0
 # CHECK-NEXT: STRXui $xzr, $x19, 0
-# CHECK-NEXT: $sp = frame-destroy ADDVL_XXI $sp, 1
 # CHECK-NEXT: $sp = frame-destroy ADDXri $fp, 0, 0
 # CHECK-NEXT: frame-destroy CFI_INSTRUCTION def_cfa $wsp, 32
 # CHECK-NEXT: $x19 = frame-destroy LDRXui $sp, 2
Index: llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
+++ llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
@@ -1953,7 +1953,10 @@
 
   // Deallocate the SVE area.
   if (SVEStackSize) {
-    if (AFI->isStackRealigned()) {
+    // If we have variable sized objects on the stack, we must also treat the
+    // stack as being realigned, so as to restore the stack pointer prior to
+    // SVE CSR restoration.
+    if (AFI->isStackRealigned() || MFI.hasVarSizedObjects()) {
       if (int64_t CalleeSavedSize = AFI->getSVECalleeSavedStackSize()) {
         // Set SP to start of SVE callee-save area from which they can
         // be reloaded. The code below will deallocate the stack space


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