llvm/test/CodeGen/X86/code-align-loops.ll

; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc < %s -mtriple=x86_64-pc-linux-gnu | FileCheck %s -check-prefixes=CHECK,ALIGN
; RUN: llc < %s -mtriple=x86_64-pc-linux-gnu -align-loops=32 | FileCheck %s -check-prefixes=CHECK,ALIGN32
; RUN: llc < %s -mtriple=x86_64-pc-linux-gnu -align-loops=256 | FileCheck %s -check-prefixes=CHECK,ALIGN256

; This test is to check if .p2align can be correctly generated by considerring
; 1. -align-loops=N from llc option
; 2. loop metadata node !{!"llvm.loop.align", i32 64}
; The test IR is generated from below simple C file:
; $ clang -S -emit-llvm loop.c
; $ cat loop.c
; void bar(void);
; void var(void);
; void foo(int a) {
;   for (int i = 0; i < a; ++i)
;     bar();
;   for (int i = 0; i < a; ++i)
;     var();
; }
; The difference between test1 and test2 is test2 only set one loop metadata node for the second loop.

; CHECK-LABEL: test1:
; ALIGN: .p2align 6
; ALIGN-NEXT: .LBB0_2: # %for.body
; ALIGN: .p2align 9
; ALIGN-NEXT: .LBB0_3: # %for.body

; ALIGN32: .p2align 6
; ALIGN32-NEXT: .LBB0_2: # %for.body
; ALIGN32: .p2align 9
; ALIGN32-NEXT: .LBB0_3: # %for.body

; ALIGN256: .p2align 8
; ALIGN256-NEXT: .LBB0_2: # %for.body
; ALIGN256: .p2align 9
; ALIGN256-NEXT: .LBB0_3: # %for.body

define void @test1(i32 %a) nounwind {
entry:
  %cmp12 = icmp sgt i32 %a, 0
  br i1 %cmp12, label %for.body, label %for.cond.cleanup4

for.body:                                         ; preds = %entry, %for.body
  %i.013 = phi i32 [ %inc, %for.body ], [ 0, %entry ]
  tail call void @bar()
  %inc = add nuw nsw i32 %i.013, 1
  %exitcond.not = icmp eq i32 %inc, %a
  br i1 %exitcond.not, label %for.body5, label %for.body, !llvm.loop !0

for.cond.cleanup4:                                ; preds = %for.body5, %entry
  ret void

for.body5:                                        ; preds = %for.body, %for.body5
  %i1.015 = phi i32 [ %inc7, %for.body5 ], [ 0, %for.body ]
  tail call void @var()
  %inc7 = add nuw nsw i32 %i1.015, 1
  %exitcond16.not = icmp eq i32 %inc7, %a
  br i1 %exitcond16.not, label %for.cond.cleanup4, label %for.body5, !llvm.loop !2
}

; CHECK-LABEL: test2:
; ALIGN: .p2align 4
; ALIGN-NEXT: .LBB1_2: # %for.body
; ALIGN: .p2align 9
; ALIGN-NEXT: .LBB1_3: # %for.body

; ALIGN32: .p2align 5
; ALIGN32-NEXT: .LBB1_2: # %for.body
; ALIGN32: .p2align 9
; ALIGN32-NEXT: .LBB1_3: # %for.body

; ALIGN256: .p2align 8
; ALIGN256-NEXT: .LBB1_2: # %for.body
; ALIGN256: .p2align 9
; ALIGN256-NEXT: .LBB1_3: # %for.body
define void @test2(i32 %a) nounwind {
entry:
  %cmp12 = icmp sgt i32 %a, 0
  br i1 %cmp12, label %for.body, label %for.cond.cleanup4

for.body:                                         ; preds = %entry, %for.body
  %i.013 = phi i32 [ %inc, %for.body ], [ 0, %entry ]
  tail call void @bar()
  %inc = add nuw nsw i32 %i.013, 1
  %exitcond.not = icmp eq i32 %inc, %a
  br i1 %exitcond.not, label %for.body5, label %for.body

for.cond.cleanup4:                                ; preds = %for.body5, %entry
  ret void

for.body5:                                        ; preds = %for.body, %for.body5
  %i1.015 = phi i32 [ %inc7, %for.body5 ], [ 0, %for.body ]
  tail call void @var()
  %inc7 = add nuw nsw i32 %i1.015, 1
  %exitcond16.not = icmp eq i32 %inc7, %a
  br i1 %exitcond16.not, label %for.cond.cleanup4, label %for.body5, !llvm.loop !2
}

; test3 and test4 is to check if .p2align can be correctly set on loops with
; multi latches. The IR is generated from below simple C file:
; $ clang -O0 -S -emit-llvm loop.c
; $ cat loop.c
; int test3() {
;     int i = 0;
;     [[clang::code_align(32)]]
;     while (i < 10) {
;         if (i % 2) {
;             continue;
;         }
;         i++;
;     }
; }
; CHECK-LABEL: test3_multilatch:
; ALIGN: .p2align 6
; ALIGN-NEXT: .LBB2_1: # %while.cond
define dso_local i32 @test3_multilatch() #0 {
entry:
  %retval = alloca i32, align 4
  %i = alloca i32, align 4
  store i32 0, ptr %retval, align 4
  store i32 0, ptr %i, align 4
  br label %while.cond

while.cond:                                       ; preds = %if.end, %if.then, %entry
  %0 = load i32, ptr %i, align 4
  %cmp = icmp slt i32 %0, 10
  br i1 %cmp, label %while.body, label %while.end

while.body:                                       ; preds = %while.cond
  %1 = load i32, ptr %i, align 4
  %rem = srem i32 %1, 2
  %tobool = icmp ne i32 %rem, 0
  br i1 %tobool, label %if.then, label %if.end

if.then:                                          ; preds = %while.body
  br label %while.cond, !llvm.loop !0

if.end:                                           ; preds = %while.body
  %2 = load i32, ptr %i, align 4
  %inc = add nsw i32 %2, 1
  store i32 %inc, ptr %i, align 4
  br label %while.cond, !llvm.loop !0

while.end:                                        ; preds = %while.cond
  %3 = load i32, ptr %retval, align 4
  ret i32 %3
}

; CHECK-LABEL: test4_multilatch:
; ALIGN: .p2align 6
; ALIGN-NEXT: .LBB3_4: # %bb4
define void @test4_multilatch(i32 %a, i32 %b, i32 %c, i32 %d) nounwind {
entry:
  br label %bb1

bb1:                               ; preds = %bb2, %bb4, %entry
  call void @bar()
  %cmp3 = icmp sgt i32 %c, 10
  br i1 %cmp3, label %bb3, label %bb4

bb2:                                ; preds = %bb3
  call void @bar()
  %cmp1 = icmp sgt i32 %a, 11
  br i1 %cmp1, label %bb1, label %exit, !llvm.loop !0

bb3:                                ; preds = %bb1
  call void @bar()
  %cmp2 = icmp sgt i32 %b, 12
  br i1 %cmp2, label %bb2, label %exit

bb4:                                ; preds = %bb1
  call void @bar()
  %cmp4 = icmp sgt i32 %d, 14
  br i1 %cmp4, label %bb1, label %exit

exit:                               ; preds = %bb2, %bb3, %bb4
  ret void
}

declare void @bar()
declare void @var()

!0 = distinct !{!0, !1}
!1 = !{!"llvm.loop.align", i32 64}
!2 = distinct !{!2, !3}
!3 = !{!"llvm.loop.align", i32 512}