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[MachineSink] Clear kill flags on operands outside loop

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If an instruction is sunk into a loop then any kill flags on
operands declared outside the loop must be cleared as these
will be live for all loop iterations.

Fixes #46827

Reviewed By: MatzeB

Differential Revision: https://reviews.llvm.org/D126754
This commit is contained in:
Carl Ritson 2022-06-24 14:02:48 +09:00
parent f401dd6f43
commit 874fbe2cbb
2 changed files with 81 additions and 0 deletions
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6
llvm/lib/CodeGen/MachineSink.cpp
View File

@ -1289,6 +1289,12 @@ bool MachineSinking::SinkIntoCycle(MachineCycle *Cycle, MachineInstr &I) {
SinkBlock->splice(SinkBlock->SkipPHIsAndLabels(SinkBlock->begin()), Preheader,
I);
// Conservatively clear any kill flags on uses of sunk instruction
for (MachineOperand &MO : I.operands()) {
if (MO.isReg() && MO.readsReg())
RegsToClearKillFlags.insert(MO.getReg());
}
// The instruction is moved from its basic block, so do not retain the
// debug information.
assert(!I.isDebugInstr() && "Should not sink debug inst");

75
llvm/test/CodeGen/SystemZ/machinelicm-sunk-kill-flags.mir Normal file
View File

@ -0,0 +1,75 @@
# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
# RUN: llc -mtriple=s390x-linux-gnu -sink-insts-to-avoid-spills -verify-machineinstrs -run-pass=machine-sink -o - %s | FileCheck %s
# Test kill flags are cleared after sinking operations into cycle during MachineLICM.
--- |
target datalayout = "E-m:e-i1:8:16-i8:8:16-i64:64-f128:64-a:8:16-n32:64"
target triple = "s390x-unknown-linux-gnu"
%0 = type <{ i32, [3 x i8] }>
@b = external dso_local global [1 x %0], align 2
define dso_local void @c() local_unnamed_addr {
ret void
}
...
---
name: c
tracksRegLiveness: true
body: |
; CHECK-LABEL: name: c
; CHECK: bb.0:
; CHECK-NEXT: successors: %bb.1(0x80000000)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: [[LARL:%[0-9]+]]:addr64bit = LARL @b
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.1:
; CHECK-NEXT: successors: %bb.1(0x80000000)
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: [[LA:%[0-9]+]]:gr64bit = LA [[LARL]], 49, $noreg
; CHECK-NEXT: [[LGHI:%[0-9]+]]:gr64bit = LGHI 7
; CHECK-NEXT: [[DEF:%[0-9]+]]:gr64bit = IMPLICIT_DEF
; CHECK-NEXT: [[DEF1:%[0-9]+]]:gr64bit = IMPLICIT_DEF
; CHECK-NEXT: ADJCALLSTACKDOWN 0, 0
; CHECK-NEXT: $r2d = COPY [[DEF]]
; CHECK-NEXT: $r3d = COPY [[LA]]
; CHECK-NEXT: $r4d = COPY [[LGHI]]
; CHECK-NEXT: CallBRASL &memcpy, $r2d, $r3d, $r4d, csr_systemz_elf, implicit-def dead $r14d, implicit-def dead $cc, implicit $fpc, implicit-def $r2d
; CHECK-NEXT: ADJCALLSTACKUP 0, 0
; CHECK-NEXT: ADJCALLSTACKDOWN 0, 0
; CHECK-NEXT: $r2d = COPY [[DEF1]]
; CHECK-NEXT: $r3d = COPY [[LA]]
; CHECK-NEXT: $r4d = COPY [[LGHI]]
; CHECK-NEXT: CallBRASL &memcpy, $r2d, $r3d, $r4d, csr_systemz_elf, implicit-def dead $r14d, implicit-def dead $cc, implicit $fpc, implicit-def $r2d
; CHECK-NEXT: ADJCALLSTACKUP 0, 0
; CHECK-NEXT: J %bb.1
bb.0:
successors: %bb.1(0x80000000)
%1:addr64bit = LARL @b
%0:gr64bit = LA killed %1, 49, $noreg
%2:gr64bit = LGHI 7
%3:gr64bit = IMPLICIT_DEF
%5:gr64bit = IMPLICIT_DEF
bb.1:
successors: %bb.1(0x80000000)
ADJCALLSTACKDOWN 0, 0
$r2d = COPY %3
$r3d = COPY %0
$r4d = COPY %2
CallBRASL &memcpy, $r2d, $r3d, $r4d, csr_systemz_elf, implicit-def dead $r14d, implicit-def dead $cc, implicit $fpc, implicit-def $r2d
ADJCALLSTACKUP 0, 0
ADJCALLSTACKDOWN 0, 0
$r2d = COPY %5
$r3d = COPY %0
$r4d = COPY %2
CallBRASL &memcpy, $r2d, $r3d, $r4d, csr_systemz_elf, implicit-def dead $r14d, implicit-def dead $cc, implicit $fpc, implicit-def $r2d
ADJCALLSTACKUP 0, 0
J %bb.1
...