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[AVR] Generate 'rcall' instead of 'call' on avr2 and avr25
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The 'call' (long call) instruction is available on avr3 and above,
and devices in avr2 and avr25 should use the 'rcall' (short call)
instruction for function calls.

Reviewed By: aykevl, dylanmckay

Differential Revision: https://reviews.llvm.org/D121539
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@benshi001
benshi001 committed Mar 23, 2022
1 parent 6edfe45 commit 4563893
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Showing 2 changed files with 61 additions and 31 deletions.
28 changes: 16 additions & 12 deletions llvm/lib/Target/AVR/AVRInstrInfo.td
View file
Expand Up @@ -194,6 +194,11 @@ def brtarget_13 : Operand<OtherVT> {
let EncoderMethod = "encodeRelCondBrTarget<AVR::fixup_13_pcrel>";
}

def rcalltarget_13 : Operand<i16> {
let PrintMethod = "printPCRelImm";
let EncoderMethod = "encodeRelCondBrTarget<AVR::fixup_13_pcrel>";
}

// The target of a 22 or 16-bit call/jmp instruction.
def call_target : Operand<iPTR> {
let EncoderMethod = "encodeCallTarget";
Expand Down Expand Up @@ -965,10 +970,8 @@ let isBarrier = 1, isBranch = 1, isTerminator = 1 in {
let isCall = 1 in {
// SP is marked as a use to prevent stack-pointer assignments that appear
// immediately before calls from potentially appearing dead.
let Uses = [SP] in def RCALLk : FBRk<1, (outs),
(ins brtarget_13
: $target),
"rcall\t$target", []>;
let Uses = [SP] in def RCALLk : FBRk<1, (outs), (ins rcalltarget_13:$k),
"rcall\t$k", [(AVRcall imm:$k)]>;

// SP is marked as a use to prevent stack-pointer assignments that appear
// immediately before calls from potentially appearing dead.
Expand All @@ -985,13 +988,10 @@ let isCall = 1 in {
// SP is marked as a use to prevent stack-pointer assignments that appear
// immediately before calls from potentially appearing dead.
//
//: TODO: the imm field can be either 16 or 22 bits in devices with more
// TODO: the imm field can be either 16 or 22 bits in devices with more
// than 64k of ROM, fix it once we support the largest devices.
let Uses = [SP] in def CALLk : F32BRk<0b111, (outs),
(ins call_target
: $k),
"call\t$k", [(AVRcall imm
: $k)]>,
let Uses = [SP] in def CALLk : F32BRk<0b111, (outs), (ins call_target:$k),
"call\t$k", [(AVRcall imm:$k)]>,
Requires<[HasJMPCALL]>;
}

Expand Down Expand Up @@ -2448,8 +2448,12 @@ def : Pat<(adde i8
: $src2))>;

// Calls.
def : Pat<(AVRcall(i16 tglobaladdr : $dst)), (CALLk tglobaladdr : $dst)>;
def : Pat<(AVRcall(i16 texternalsym : $dst)), (CALLk texternalsym : $dst)>;
let Predicates = [HasJMPCALL] in {
def : Pat<(AVRcall(i16 tglobaladdr:$dst)), (CALLk tglobaladdr:$dst)>;
def : Pat<(AVRcall(i16 texternalsym:$dst)), (CALLk texternalsym:$dst)>;
}
def : Pat<(AVRcall(i16 tglobaladdr:$dst)), (RCALLk tglobaladdr:$dst)>;
def : Pat<(AVRcall(i16 texternalsym:$dst)), (RCALLk texternalsym:$dst)>;

// `anyext`
def : Pat<(i16(anyext i8
Expand Down
64 changes: 45 additions & 19 deletions llvm/test/CodeGen/AVR/call.ll
View file
@@ -1,4 +1,5 @@
; RUN: llc < %s -march=avr -mattr=avr6 | FileCheck %s
; RUN: llc < %s -mtriple=avr -mcpu=avr6 | FileCheck %s --check-prefixes=CHECK,AVR6
; RUN: llc < %s -mtriple=avr -mcpu=avr2 | FileCheck %s --check-prefixes=CHECK,AVR2

; TODO: test returning byval structs

Expand All @@ -18,11 +19,13 @@ declare i64 @foo64_2(i64, i64, i64)
define i8 @calli8_reg() {
; CHECK-LABEL: calli8_reg:
; CHECK: ldi r24, 12
; CHECK: call foo8_1
; AVR6: call foo8_1
; AVR2: rcall foo8_1
; CHECK: ldi r24, 12
; CHECK: ldi r22, 13
; CHECK: ldi r20, 14
; CHECK: call foo8_2
; AVR6: call foo8_2
; AVR2: rcall foo8_2
%result1 = call i8 @foo8_1(i8 12)
%result2 = call i8 @foo8_2(i8 12, i8 13, i8 14)
ret i8 %result2
Expand All @@ -34,7 +37,8 @@ define i8 @calli8_stack() {
; CHECK: ldi [[REG2:r[0-9]+]], 11
; CHECK: std Z+1, [[REG1]]
; CHECK: std Z+2, [[REG2]]
; CHECK: call foo8_3
; AVR6: call foo8_3
; AVR2: rcall foo8_3
%result1 = call i8 @foo8_3(i8 1, i8 2, i8 3, i8 4, i8 5, i8 6, i8 7, i8 8, i8 9, i8 10, i8 11)
ret i8 %result1
}
Expand All @@ -45,7 +49,8 @@ define i16 @calli16_reg() {
; CHECK: ldi r25, 2
; CHECK: ldi r22, 2
; CHECK: ldi r23, 2
; CHECK: call foo16_1
; AVR6: call foo16_1
; AVR2: rcall foo16_1
%result1 = call i16 @foo16_1(i16 513, i16 514)
ret i16 %result1
}
Expand All @@ -60,7 +65,8 @@ define i16 @calli16_stack() {
; CHECK: ldi [[REG2:r[0-9]+]], 2
; CHECK: std Z+1, [[REG1]]
; CHECK: std Z+2, [[REG2]]
; CHECK: call foo16_2
; AVR6: call foo16_2
; AVR2: rcall foo16_2
%result1 = call i16 @foo16_2(i16 512, i16 513, i16 514, i16 515, i16 516, i16 517, i16 518, i16 519, i16 520, i16 521, i16 522)
ret i16 %result1
}
Expand All @@ -75,7 +81,8 @@ define i32 @calli32_reg() {
; CHECK: ldi r19, 132
; CHECK: ldi r20, 30
; CHECK: ldi r21, 2
; CHECK: call foo32_1
; AVR6: call foo32_1
; AVR2: rcall foo32_1
%result1 = call i32 @foo32_1(i32 34554432, i32 35554432)
ret i32 %result1
}
Expand All @@ -90,7 +97,8 @@ define i32 @calli32_stack() {
; CHECK: ldi [[REG2:r[0-9]+]], 66
; CHECK: std Z+1, [[REG1]]
; CHECK: std Z+2, [[REG2]]
; CHECK: call foo32_2
; AVR6: call foo32_2
; AVR2: rcall foo32_2
%result1 = call i32 @foo32_2(i32 1, i32 2, i32 3, i32 4, i32 34554432)
ret i32 %result1
}
Expand All @@ -105,7 +113,8 @@ define i64 @calli64_reg() {
; CHECK: ldi r23, 73
; CHECK: ldi r24, 31
; CHECK: ldi r25, 242
; CHECK: call foo64_1
; AVR6: call foo64_1
; AVR2: rcall foo64_1
%result1 = call i64 @foo64_1(i64 17446744073709551615)
ret i64 %result1
}
Expand All @@ -129,7 +138,8 @@ define i64 @calli64_stack() {
; CHECK: ldi [[REG2:r[0-9]+]], 255
; CHECK: std Z+1, [[REG1]]
; CHECK: std Z+2, [[REG2]]
; CHECK: call foo64_2
; AVR6: call foo64_2
; AVR2: rcall foo64_2
%result1 = call i64 @foo64_2(i64 1, i64 2, i64 17446744073709551615)
ret i64 %result1
}
Expand Down Expand Up @@ -171,7 +181,9 @@ define void @testcallprologue() {

define i32 @icall(i32 (i32) addrspace(1)* %foo) {
; CHECK-LABEL: icall:
; CHECK: movw r30, r24
; AVR6: movw r30, r24
; AVR2: mov r30, r24
; AVR2: mov r31, r25
; CHECK: ldi r22, 147
; CHECK: ldi r23, 248
; CHECK: ldi r24, 214
Expand All @@ -192,14 +204,28 @@ declare i32 @foofloat(float)

define i32 @externcall(float %a, float %b) {
; CHECK-LABEL: externcall:
; CHECK: movw [[REG1:(r[0-9]+|[XYZ])]], r24
; CHECK: movw [[REG2:(r[0-9]+|[XYZ])]], r22
; CHECK: movw r22, r18
; CHECK: movw r24, r20
; CHECK: movw r18, [[REG2]]
; CHECK: movw r20, [[REG1]]
; CHECK: call __divsf3
; CHECK: call foofloat
; AVR6: movw [[REG0:(r[0-9]+|[XYZ])]], r24
; AVR6: movw [[REG1:(r[0-9]+|[XYZ])]], r22
; AVR6: movw r22, r18
; AVR6: movw r24, r20
; AVR6: movw r18, [[REG1]]
; AVR6: movw r20, [[REG0]]
; AVR6: call __divsf3
; AVR6: call foofloat
; AVR2: mov [[REG0:(r[0-9]+)]], r24
; AVR2: mov [[REG1:(r[0-9]+)]], r25
; AVR2: mov [[REG2:(r[0-9]+)]], r22
; AVR2: mov [[REG3:(r[0-9]+)]], r23
; AVR2: mov r22, r18
; AVR2: mov r23, r19
; AVR2: mov r24, r20
; AVR2: mov r25, r21
; AVR2: mov r18, [[REG2]]
; AVR2: mov r19, [[REG3]]
; AVR2: mov r20, [[REG0]]
; AVR2: mov r21, [[REG1]]
; AVR2: rcall __divsf3
; AVR2: rcall foofloat
; CHECK: subi r22, 251
; CHECK: sbci r23, 255
; CHECK: sbci r24, 255
Expand Down

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