d1d3005c9f
The attiny4/attiny5/attiny9/attiny10 have a slightly modified
instruction set that drops a number of useful instructions. This patch
makes sure to not emit them on these "reduced tiny" cores.
The affected instructions are:
* lds and sts (load/store directly from data)
* ldd and std (load/store with displacement)
* adiw and sbiw (add/sub register pairs)
* various other instructions that were emitted without checking
whether the chip actually supports them (movw, adiw, etc)
There is a variant on lds and sts on these chips, but it can only
address a limited portion of the address space and is mainly useful to
load/store I/O registers (as an extension to the in and out
instructions). I have not implemented it here, implementing it can be
done in a separate patch.
This patch is not optimal. I'm sure it can be improved a lot. For
example, we could teach the instruction selector to not select lddw/stdw
instructions so that the weird pointer adjustments are not necessary.
But for now I've focused just on correctness, not on code quality.
Updates: https://github.com/llvm/llvm-project/issues/53459
Differential Revision: https://reviews.llvm.org/D131867
35 lines
1.1 KiB
YAML
35 lines
1.1 KiB
YAML
# RUN: llc -O0 -run-pass=avr-expand-pseudo %s -o - | FileCheck %s
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# RUN: llc -O0 -run-pass=avr-expand-pseudo -mattr=avrtiny %s -o - | FileCheck %s --check-prefix=CHECK-TINY
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# This test checks the expansion of the 16-bit 'LDDWRdPtrQ' pseudo instruction.
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--- |
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target triple = "avr--"
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define void @test_lddwrdptrq() {
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entry:
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ret void
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}
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...
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---
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name: test_lddwrdptrq
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tracksRegLiveness: true
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body: |
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bb.0.entry:
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liveins: $r31r30
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; CHECK-LABEL: test_lddwrdptrq
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; CHECK: $r24 = LDDRdPtrQ $r31r30, 10
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; CHECK-NEXT: $r25 = LDDRdPtrQ $r31r30, 11
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; CHECK-TINY: $r30 = SUBIRdK $r30, 246, implicit-def $sreg
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; CHECK-TINY-NEXT: $r31 = SBCIRdK $r31, 255, implicit-def $sreg, implicit killed $sreg
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; CHECK-TINY-NEXT: $r24, $r31r30 = LDRdPtrPi killed $r31r30
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; CHECK-TINY-NEXT: $r25, $r31r30 = LDRdPtrPi killed $r31r30
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; CHECK-TINY-NEXT: $r30 = SUBIRdK $r30, 12, implicit-def $sreg
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; CHECK-TINY-NEXT: $r31 = SBCIRdK $r31, 0, implicit-def $sreg, implicit killed $sreg
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early-clobber $r25r24 = LDDWRdPtrQ undef $r31r30, 10
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...
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