[PATCH] D111133: [AARCH64] Teach AArch64FrameLowering::getFrameIndexReferencePreferSP really prefer SP.

[Serguei Katkov via Phabricator via llvm-commits]

skatkov created this revision.
skatkov added reviewers: reames, loicottet, ostannard.
Herald added subscribers: arphaman, hiraditya, kristof.beyls.
skatkov requested review of this revision.
Herald added a project: LLVM.

Make more efforts to use sp even if fp is present in method.

This is used by STATEPOINT instruction.


https://reviews.llvm.org/D111133

Files:
  llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
  llvm/test/CodeGen/AArch64/statepoint-call-lowering-sp.ll


Index: llvm/test/CodeGen/AArch64/statepoint-call-lowering-sp.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AArch64/statepoint-call-lowering-sp.ll
@@ -0,0 +1,23 @@
+; RUN: llc -mtriple aarch64-none-linux-gnu -verify-machineinstrs -stop-after=prologepilog < %s | FileCheck %s
+
+; Check that STATEPOINT instruction prefer to use sp in presense of fp.
+target datalayout = "e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "aarch64-unknown-linux-gnu"
+
+declare void @consume(i32 addrspace(1)* %obj)
+
+define i1 @test(i32 addrspace(1)* %a) "frame-pointer"="all" gc "statepoint-example" {
+entry:
+  %safepoint_token = tail call token (i64, i32, i1 ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_i1f(i64 0, i32 0, i1 ()* @return_i1, i32 0, i32 0, i32 0, i32 0) ["gc-live" (i32 addrspace(1)* %a)]
+; CHECK: STATEPOINT 0, 0, 0, @return_i1, 2, 0, 2, 0, 2, 0, 2, 1, 1, 8, $sp, 24, 2, 0, 2, 1, 0, 0
+  %call1 = call i32 addrspace(1)* @llvm.experimental.gc.relocate.p1i32(token %safepoint_token,  i32 0, i32 0)
+  %call2 = call zeroext i1 @llvm.experimental.gc.result.i1(token %safepoint_token)
+  call void @consume(i32 addrspace(1)* %call1)
+  ret i1 %call2
+}
+
+
+declare i1 @return_i1()
+declare token @llvm.experimental.gc.statepoint.p0f_i1f(i64, i32, i1 ()*, i32, i32, ...)
+declare i32 addrspace(1)* @llvm.experimental.gc.relocate.p1i32(token, i32, i32)
+declare i1 @llvm.experimental.gc.result.i1(token)
Index: llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
+++ llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
@@ -3533,6 +3533,19 @@
     FrameReg = AArch64::SP;
     return StackOffset::getFixed(MFI.getObjectOffset(FI));
   }
+  if (!MFI.hasVarSizedObjects()) {
+    FrameReg = AArch64::SP;
+    bool isFixed = MFI.isFixedObjectIndex(FI);
+    int64_t ObjectOffset = MFI.getObjectOffset(FI);
+    const auto *AFI = MF.getInfo<AArch64FunctionInfo>();
+    bool isCSR =
+        !isFixed && ObjectOffset >= -((int)AFI->getCalleeSavedStackSize(MFI));
+    int64_t Offset = getStackOffset(MF, ObjectOffset).getFixed();
+    StackOffset ScalableOffset = {};
+    if (isFixed || isCSR)
+      ScalableOffset = getSVEStackSize(MF);
+    return StackOffset::getFixed(Offset) + ScalableOffset;
+  }
 
   return getFrameIndexReference(MF, FI, FrameReg);
 }


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