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[STATEPOINT] Mark LR is early-clobber implicit def. 

LR is modified at the moment of the call and before any use is read.

Reviewers: reames
Reviewed By: reames
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D120114
This commit is contained in:
Serguei Katkov 2022-02-18 18:10:14 +07:00
parent 7b67d2e398
commit 7f2293ba25
2 changed files with 24 additions and 3 deletions
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11
llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
View File

@ -2353,9 +2353,14 @@ MachineBasicBlock *AArch64TargetLowering::EmitInstrWithCustomInserter(
case TargetOpcode::STATEPOINT:
// STATEPOINT is a pseudo instruction which has no implicit defs/uses
// while bl call instruction (where statepoint will be lowered at the end)
// has implicit def. Add this implicit dead def here as a workaround.
MI.addOperand(*MI.getMF(), MachineOperand::CreateReg(AArch64::LR, true,
true, false, true));
// has implicit def. This def is early-clobber as it will be set at
// the moment of the call and earlier than any use is read.
// Add this implicit dead def here as a workaround.
MI.addOperand(*MI.getMF(),
MachineOperand::CreateReg(
AArch64::LR, /*isDef*/ true,
/*isImp*/ true, /*isKill*/ false, /*isDead*/ true,
/*isUndef*/ false, /*isEarlyClobber*/ true));
LLVM_FALLTHROUGH;
case TargetOpcode::STACKMAP:
case TargetOpcode::PATCHPOINT:

16
llvm/test/CodeGen/AArch64/statepoint-call-lowering-lr.ll Normal file
View File

@ -0,0 +1,16 @@
; RUN: llc -mtriple aarch64-none-linux-gnu -verify-machineinstrs -stop-after=prologepilog < %s | FileCheck %s
; Check that STATEPOINT instruction has an early clobber implicit def for LR.
target datalayout = "e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "aarch64-unknown-linux-gnu"
define void @test() "frame-pointer"="all" gc "statepoint-example" {
entry:
%safepoint_token = tail call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_i1f(i64 0, i32 0, void ()* elementtype(void ()) @return_i1, i32 0, i32 0, i32 0, i32 0) ["gc-live" ()]
; CHECK: STATEPOINT 0, 0, 0, @return_i1, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, csr_aarch64_aapcs, implicit-def $sp, implicit-def dead early-clobber $lr
ret void
}
declare void @return_i1()
declare token @llvm.experimental.gc.statepoint.p0f_i1f(i64, i32, void ()*, i32, i32, ...)