llvm/test/CodeGen/X86/fake-use-scheduler.mir

# Prevent the machine scheduler from moving instructions past FAKE_USE.
# RUN: llc -run-pass machine-scheduler -mtriple=x86_64-unknown-linux -debug-only=machine-scheduler 2>&1 -o - %s | FileCheck %s
# REQUIRES: asserts
#
# We make sure that, beginning with the first FAKE_USE instruction,
# no changes to the sequence of instructions are undertaken by the
# scheduler. We don't bother to check that the order of the FAKE_USEs
# remains the same. They should, but it is irrelevant.
#
# CHECK: ********** MI Scheduling **********
# CHECK-NEXT: foo:%bb.0 entry
# CHECK-NEXT:   From: %0:gr64 = COPY $rdi
# CHECK-NEXT:     To: FAKE_USE %5:gr64
# CHECK-NEXT:  RegionInstrs: 7
#
# CHECK: ********** MI Scheduling **********
# CHECK-NEXT: bar:%bb.0 entry
# CHECK-NEXT:   From: %0:gr64 = COPY $rdi
# CHECK-NEXT:     To: RET 0, killed $rax
# CHECK-NEXT:  RegionInstrs: 7
#
--- |
  ; ModuleID = 'test.ll'
  source_filename = "test.ll"
  target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
  
  @glb = common dso_local local_unnamed_addr global [100 x i32] zeroinitializer, align 16
  
  define dso_local i64 @foo(ptr %p) local_unnamed_addr optdebug {
  entry:
    %0 = load i32, ptr @glb, align 16
    store i32 %0, ptr %p, align 4
    %conv = sext i32 %0 to i64
    %1 = load i32, ptr getelementptr inbounds ([100 x i32], ptr @glb, i64 0, i64 1), align 4
    %arrayidx1 = getelementptr inbounds i32, ptr %p, i64 1
    store i32 %1, ptr %arrayidx1, align 4
    %conv2 = sext i32 %1 to i64
    %add3 = add nsw i64 %conv2, %conv
    notail call void (...) @llvm.fake.use(i64 %add3)
    notail call void (...) @llvm.fake.use(i32 %1)
    notail call void (...) @llvm.fake.use(i32 %0)
    notail call void (...) @llvm.fake.use(ptr %p)
    ret i64 %add3
  }
  
  define dso_local i64 @bar(ptr %p) local_unnamed_addr optdebug {
  entry:
    %0 = load i32, ptr @glb, align 16
    store i32 %0, ptr %p, align 4
    %conv = sext i32 %0 to i64
    %1 = load i32, ptr getelementptr inbounds ([100 x i32], ptr @glb, i64 0, i64 1), align 4
    %arrayidx1 = getelementptr inbounds i32, ptr %p, i64 1
    store i32 %1, ptr %arrayidx1, align 4
    %conv2 = sext i32 %1 to i64
    %add3 = add nsw i64 %conv2, %conv
    ret i64 %add3
  }
  
  ; Function Attrs: nocallback nofree nosync nounwind willreturn
  declare void @llvm.stackprotector(ptr, ptr)
  
...
---
name:            foo
alignment:       16
tracksRegLiveness: true
debugInstrRef:   true
registers:
  - { id: 0, class: gr64, preferred-register: '' }
  - { id: 1, class: gr64_with_sub_8bit, preferred-register: '' }
  - { id: 2, class: gr32, preferred-register: '' }
  - { id: 3, class: gr64_with_sub_8bit, preferred-register: '' }
  - { id: 4, class: gr32, preferred-register: '' }
  - { id: 5, class: gr64, preferred-register: '' }
liveins:
  - { reg: '$rdi', virtual-reg: '%0' }
body:             |
  bb.0.entry:
    liveins: $rdi
  
    %0:gr64 = COPY $rdi
    %1:gr64_with_sub_8bit = MOVSX64rm32 $rip, 1, $noreg, @glb, $noreg
    MOV32mr %0, 1, $noreg, 0, $noreg, %1.sub_32bit
    %3:gr64_with_sub_8bit = MOVSX64rm32 $rip, 1, $noreg, @glb + 4, $noreg
    MOV32mr %0, 1, $noreg, 4, $noreg, %3.sub_32bit
    %5:gr64 = COPY %3
    %5:gr64 = nsw ADD64rr %5, %1, implicit-def dead $eflags
    FAKE_USE %5
    FAKE_USE %3.sub_32bit
    FAKE_USE %1.sub_32bit
    FAKE_USE %0
    $rax = COPY %5
    RET 0, killed $rax

...
---
name:            bar
alignment:       16
tracksRegLiveness: true
debugInstrRef:   true
registers:
  - { id: 0, class: gr64, preferred-register: '' }
  - { id: 1, class: gr64_with_sub_8bit, preferred-register: '' }
  - { id: 2, class: gr32, preferred-register: '' }
  - { id: 3, class: gr64_with_sub_8bit, preferred-register: '' }
  - { id: 4, class: gr32, preferred-register: '' }
  - { id: 5, class: gr64_with_sub_8bit, preferred-register: '' }
liveins:
  - { reg: '$rdi', virtual-reg: '%0' }
body:             |
  bb.0.entry:
    liveins: $rdi
  
    %0:gr64 = COPY $rdi
    %1:gr64_with_sub_8bit = MOVSX64rm32 $rip, 1, $noreg, @glb, $noreg
    MOV32mr %0, 1, $noreg, 0, $noreg, %1.sub_32bit
    %5:gr64_with_sub_8bit = MOVSX64rm32 $rip, 1, $noreg, @glb + 4, $noreg
    MOV32mr %0, 1, $noreg, 4, $noreg, %5.sub_32bit
    %5:gr64_with_sub_8bit = nsw ADD64rr %5, %1, implicit-def dead $eflags
    $rax = COPY %5
    RET 0, killed $rax

...