[PATCH] D136579: [AArch64][SME] Fix chain for arm_locally_streaming functions.

[Sander de Smalen via Phabricator via llvm-commits]

sdesmalen created this revision.
sdesmalen added reviewers: aemerson, david-arm, kmclaughlin.
Herald added subscribers: hiraditya, kristof.beyls.
Herald added a project: All.
sdesmalen requested review of this revision.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

The Chain wasn't set correctly in the DAG for functions marked
with aarch64_pstate_sm_body, which meant that SelectionDAG would
dead-code some of the CopyToReg's. This didn't show up in the
existing tests because all uses were in the same block, but when
adding some control-flow, suddenly things would break.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D136579

Files:
  llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
  llvm/test/CodeGen/AArch64/sme-streaming-body.ll


Index: llvm/test/CodeGen/AArch64/sme-streaming-body.ll
===================================================================
--- llvm/test/CodeGen/AArch64/sme-streaming-body.ll
+++ llvm/test/CodeGen/AArch64/sme-streaming-body.ll
@@ -263,3 +263,46 @@
 }
 
 declare double @llvm.cos.f64(double)
+
+
+define float @test_arg_survives_loop(float %arg, i32 %N) nounwind "aarch64_pstate_sm_body" {
+; CHECK-LABEL: test_arg_survives_loop:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    sub sp, sp, #80
+; CHECK-NEXT:    stp d15, d14, [sp, #16] // 16-byte Folded Spill
+; CHECK-NEXT:    stp d13, d12, [sp, #32] // 16-byte Folded Spill
+; CHECK-NEXT:    stp d11, d10, [sp, #48] // 16-byte Folded Spill
+; CHECK-NEXT:    stp d9, d8, [sp, #64] // 16-byte Folded Spill
+; CHECK-NEXT:    str s0, [sp, #12] // 4-byte Folded Spill
+; CHECK-NEXT:    smstart sm
+; CHECK-NEXT:  .LBB9_1: // %for.body
+; CHECK-NEXT:    // =>This Inner Loop Header: Depth=1
+; CHECK-NEXT:    subs w0, w0, #1
+; CHECK-NEXT:    b.ne .LBB9_1
+; CHECK-NEXT:  // %bb.2: // %for.cond.cleanup
+; CHECK-NEXT:    fmov s0, #1.00000000
+; CHECK-NEXT:    ldr s1, [sp, #12] // 4-byte Folded Reload
+; CHECK-NEXT:    fadd s0, s1, s0
+; CHECK-NEXT:    str s0, [sp, #12] // 4-byte Folded Spill
+; CHECK-NEXT:    smstop sm
+; CHECK-NEXT:    ldp d9, d8, [sp, #64] // 16-byte Folded Reload
+; CHECK-NEXT:    ldp d11, d10, [sp, #48] // 16-byte Folded Reload
+; CHECK-NEXT:    ldp d13, d12, [sp, #32] // 16-byte Folded Reload
+; CHECK-NEXT:    ldp d15, d14, [sp, #16] // 16-byte Folded Reload
+; CHECK-NEXT:    ldr s0, [sp, #12] // 4-byte Folded Reload
+; CHECK-NEXT:    add sp, sp, #80
+; CHECK-NEXT:    ret
+entry:
+  br label %for.body
+
+for.body:
+  %i.02 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+  %inc = add nuw nsw i32 %i.02, 1
+  %exitcond.not = icmp eq i32 %inc, %N
+  br i1 %exitcond.not, label %for.cond.cleanup, label %for.body
+
+for.cond.cleanup:
+  %add = fadd float %arg, 1.000000e+00
+  ret float %add
+
+}
Index: llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -6302,8 +6302,8 @@
     for (unsigned I=0; I<InVals.size(); ++I) {
       Register Reg = MF.getRegInfo().createVirtualRegister(
           getRegClassFor(InVals[I].getValueType().getSimpleVT()));
-      SDValue X = DAG.getCopyToReg(Chain, DL, Reg, InVals[I]);
-      InVals[I] = DAG.getCopyFromReg(X, DL, Reg,
+      Chain = DAG.getCopyToReg(Chain, DL, Reg, InVals[I]);
+      InVals[I] = DAG.getCopyFromReg(Chain, DL, Reg,
                                      InVals[I].getValueType());
     }
   }


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D136579.470063.patch
Type: text/x-patch
Size: 2708 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20221024/ee28e3ee/attachment.bin>