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llvm-mirror/test/CodeGen/AVR/rot.ll
Ayke van Laethem 8ded1a7aa8 [AVR] Fix rotate instructions
This patch fixes some issues with the RORB pseudo instruction.

  - A minor issue in which the instructions were said to use the SREG,
    which is not true.
  - An issue with the BLD instruction, which did not have an output operand.
  - A major issue in which invalid instructions were generated. The fix
    also reduce RORB from 4 to 3 instructions, so it's also a small
    optimization.

These issues were flagged by the machine verifier.

Differential Revision: https://reviews.llvm.org/D96957
2021-07-24 14:03:26 +02:00

59 lines
1.0 KiB
LLVM

; RUN: llc < %s -march=avr | FileCheck %s
; Bit rotation tests.
; CHECK-LABEL: rol8:
define i8 @rol8(i8 %val, i8 %amt) {
; CHECK: andi r22, 7
; CHECK-NEXT: dec r22
; CHECK-NEXT: brmi .LBB0_2
; CHECK-NEXT: .LBB0_1:
; CHECK-NEXT: lsl r24
; CHECK-NEXT: adc r24, r1
; CHECK-NEXT: dec r22
; CHECK-NEXT: brpl .LBB0_1
; CHECK-NEXT: .LBB0_2:
; CHECK-NEXT: ret
%mod = urem i8 %amt, 8
%inv = sub i8 8, %mod
%parta = shl i8 %val, %mod
%partb = lshr i8 %val, %inv
%rotl = or i8 %parta, %partb
ret i8 %rotl
}
; CHECK-LABEL: ror8:
define i8 @ror8(i8 %val, i8 %amt) {
; CHECK: andi r22, 7
; CHECK-NEXT: dec r22
; CHECK-NEXT: brmi .LBB1_2
; CHECK-NEXT: .LBB1_1:
; CHECK-NEXT: bst r24, 0
; CHECK-NEXT: ror r24
; CHECK-NEXT: bld r24, 7
; CHECK-NEXT: dec r22
; CHECK-NEXT: brpl .LBB1_1
; CHECK-NEXT: .LBB1_2:
; CHECK-NEXT: ret
%mod = urem i8 %amt, 8
%inv = sub i8 8, %mod
%parta = lshr i8 %val, %mod
%partb = shl i8 %val, %inv
%rotr = or i8 %parta, %partb
ret i8 %rotr
}