f7f44f018f
Setting up a lazy-save mechanism around calls is done during SelectionDAG because calls to intrinsics may be expanded into an actual function call (e.g. calls to @llvm.cos()), and maintaining an allowed-list in the SMEABI pass is not feasible. The approach for conditionally restoring the lazy-save based on the runtime value of TPIDR2_EL0 is similar to how we handle conditional smstart/smstop. We create a pseudo-node which gets expanded into a conditional branch and expands to a call to __arm_tpidr2_restore(%tpidr2_object_ptr). The lazy-save buffer and TPIDR2 block are only allocated once at the start of the function. For each call, the TPIDR2 block is initialised, and at the end of the call, a pseudo node (RestoreZA) is planted. Patch by Sander de Smalen. Differential Revision: https://reviews.llvm.org/D133900
69 lines
2.4 KiB
LLVM
69 lines
2.4 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
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; RUN: llc -mtriple=aarch64-linux-gnu -mattr=+sme -verify-machineinstrs < %s | FileCheck %s
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declare void @private_za_callee()
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; Ensure that we don't use tail call optimization when a lazy-save is required.
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define void @disable_tailcallopt() "aarch64_pstate_za_shared" nounwind {
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; CHECK-LABEL: disable_tailcallopt:
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; CHECK: // %bb.0:
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; CHECK-NEXT: stp x29, x30, [sp, #-16]! // 16-byte Folded Spill
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; CHECK-NEXT: mov x29, sp
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; CHECK-NEXT: sub sp, sp, #16
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; CHECK-NEXT: rdsvl x8, #1
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; CHECK-NEXT: mov x9, sp
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; CHECK-NEXT: mul x8, x8, x8
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; CHECK-NEXT: sub x9, x9, x8
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; CHECK-NEXT: mov sp, x9
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; CHECK-NEXT: sub x10, x29, #16
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; CHECK-NEXT: str x9, [x29]
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; CHECK-NEXT: sturh w8, [x29, #-8]
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; CHECK-NEXT: msr TPIDR2_EL0, x10
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; CHECK-NEXT: bl private_za_callee
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; CHECK-NEXT: smstart za
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; CHECK-NEXT: sub x0, x29, #16
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; CHECK-NEXT: mrs x8, TPIDR2_EL0
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; CHECK-NEXT: cbnz x8, .LBB0_2
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; CHECK-NEXT: // %bb.1:
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; CHECK-NEXT: bl __arm_tpidr2_restore
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; CHECK-NEXT: .LBB0_2:
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; CHECK-NEXT: msr TPIDR2_EL0, xzr
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; CHECK-NEXT: mov sp, x29
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; CHECK-NEXT: ldp x29, x30, [sp], #16 // 16-byte Folded Reload
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; CHECK-NEXT: ret
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tail call void @private_za_callee()
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ret void
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}
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; Ensure we set up and restore the lazy save correctly for instructions which are lowered to lib calls
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define fp128 @f128_call_za(fp128 %a, fp128 %b) "aarch64_pstate_za_shared" nounwind {
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; CHECK-LABEL: f128_call_za:
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; CHECK: // %bb.0:
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; CHECK-NEXT: stp x29, x30, [sp, #-16]! // 16-byte Folded Spill
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; CHECK-NEXT: mov x29, sp
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; CHECK-NEXT: sub sp, sp, #16
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; CHECK-NEXT: rdsvl x8, #1
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; CHECK-NEXT: mov x9, sp
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; CHECK-NEXT: mul x8, x8, x8
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; CHECK-NEXT: sub x9, x9, x8
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; CHECK-NEXT: mov sp, x9
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; CHECK-NEXT: sub x10, x29, #16
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; CHECK-NEXT: sturh w8, [x29, #-8]
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; CHECK-NEXT: str x9, [x29]
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; CHECK-NEXT: msr TPIDR2_EL0, x10
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; CHECK-NEXT: bl __addtf3
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; CHECK-NEXT: smstart za
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; CHECK-NEXT: add x0, x29, #0
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; CHECK-NEXT: mrs x8, TPIDR2_EL0
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; CHECK-NEXT: cbnz x8, .LBB1_2
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; CHECK-NEXT: // %bb.1:
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; CHECK-NEXT: bl __arm_tpidr2_restore
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; CHECK-NEXT: .LBB1_2:
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; CHECK-NEXT: msr TPIDR2_EL0, xzr
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; CHECK-NEXT: mov sp, x29
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; CHECK-NEXT: ldp x29, x30, [sp], #16 // 16-byte Folded Reload
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; CHECK-NEXT: ret
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%res = fadd fp128 %a, %b
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ret fp128 %res
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}
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