diff options
| -rw-r--r-- | llvm/lib/CodeGen/MachineSink.cpp | 16 | ||||
| -rw-r--r-- | llvm/test/CodeGen/AArch64/fast-isel-machine-sink.ll | 27 |
2 files changed, 40 insertions, 3 deletions
diff --git a/llvm/lib/CodeGen/MachineSink.cpp b/llvm/lib/CodeGen/MachineSink.cpp index 81aaca02a4d..0c29c76309e 100644 --- a/llvm/lib/CodeGen/MachineSink.cpp +++ b/llvm/lib/CodeGen/MachineSink.cpp @@ -736,9 +736,19 @@ bool MachineSinking::SinkInstruction(MachineInstr *MI, bool &SawStore) { ++MachineBasicBlock::iterator(DbgMI)); } - // Conservatively, clear any kill flags, since it's possible that they are no - // longer correct. - MI->clearKillInfo(); + // When sinking the instruction the live time of its operands can be extended + // bejond their original last use (marked with a kill flag). Conservatively + // clear the kill flag in all instructions that use the same operand + // registers. + for (auto &MO : MI->uses()) + if (MO.isReg() && MO.isUse()) { + // Preserve the kill flag for this instruction. + bool IsKill = MO.isKill(); + // Clear the kill flag in all instruction that use this operand. + MRI->clearKillFlags(MO.getReg()); + // Restore the kill flag for only this instruction. + MO.setIsKill(IsKill); + } return true; } diff --git a/llvm/test/CodeGen/AArch64/fast-isel-machine-sink.ll b/llvm/test/CodeGen/AArch64/fast-isel-machine-sink.ll new file mode 100644 index 00000000000..74d3e8dbad0 --- /dev/null +++ b/llvm/test/CodeGen/AArch64/fast-isel-machine-sink.ll @@ -0,0 +1,27 @@ +; RUN: llc -mtriple=aarch64-apple-darwin -fast-isel -verify-machineinstrs < %s + +define void @test() { + %sext = shl i64 undef, 32 + %1 = ashr exact i64 %sext, 32 + %2 = icmp sgt i64 undef, %1 + br i1 %2, label %3, label %.critedge1 + +; <label>:3 ; preds = %0 + %4 = getelementptr inbounds i32* undef, i64 %1 + %5 = load i32* %4, align 4 + br i1 undef, label %6, label %.critedge1 + +; <label>:6 ; preds = %3 + %7 = and i32 %5, 255 + %8 = icmp eq i32 %7, 255 + br i1 %8, label %.lr.ph, label %._crit_edge + +.lr.ph: ; preds = %.lr.ph, %6 + br i1 undef, label %.lr.ph, label %.critedge1 + +._crit_edge: ; preds = %6 + ret void + +.critedge1: ; preds = %.lr.ph, %3, %0 + ret void +} |
