llvm-project/llvm/test/Analysis/ScalarEvolution/trip-count14.ll

; RUN: opt -S -analyze -scalar-evolution < %s | FileCheck %s

define void @s32_max1(i32 %n, i32* %p) {
entry:
  %add = add i32 %n, 1
  br label %do.body

do.body:
  %i.0 = phi i32 [ %n, %entry ], [ %inc, %do.body ]
  %arrayidx = getelementptr i32, i32* %p, i32 %i.0
  store i32 %i.0, i32* %arrayidx, align 4
  %inc = add i32 %i.0, 1
  %cmp = icmp slt i32 %i.0, %add
  br i1 %cmp, label %do.body, label %do.end ; taken either 0 or 1 times

; CHECK-LABEL: Determining loop execution counts for: @s32_max1
; CHECK-NEXT: Loop %do.body: backedge-taken count is ((-1 * %n) + ((1 + %n) smax %n))
; CHECK-NEXT: Loop %do.body: max backedge-taken count is 1, actual taken count either this or zero.

do.end:
  ret void
}

define void @s32_max2(i32 %n, i32* %p) {
entry:
  %add = add i32 %n, 2
  br label %do.body

do.body:
  %i.0 = phi i32 [ %n, %entry ], [ %inc, %do.body ]
  %arrayidx = getelementptr i32, i32* %p, i32 %i.0
  store i32 %i.0, i32* %arrayidx, align 4
  %inc = add i32 %i.0, 1
  %cmp = icmp slt i32 %i.0, %add
  br i1 %cmp, label %do.body, label %do.end ; taken either 0 or 2 times

; CHECK-LABEL: Determining loop execution counts for: @s32_max2
; CHECK-NEXT: Loop %do.body: backedge-taken count is ((-1 * %n) + ((2 + %n) smax %n))
; CHECK-NEXT: Loop %do.body: max backedge-taken count is 2, actual taken count either this or zero.

do.end:
  ret void
}

define void @s32_maxx(i32 %n, i32 %x, i32* %p) {
entry:
  %add = add i32 %x, %n
  br label %do.body

do.body:
  %i.0 = phi i32 [ %n, %entry ], [ %inc, %do.body ]
  %arrayidx = getelementptr i32, i32* %p, i32 %i.0
  store i32 %i.0, i32* %arrayidx, align 4
  %inc = add i32 %i.0, 1
  %cmp = icmp slt i32 %i.0, %add
  br i1 %cmp, label %do.body, label %do.end ; taken either 0 or x times

; CHECK-LABEL: Determining loop execution counts for: @s32_maxx
; CHECK-NEXT: Loop %do.body: backedge-taken count is ((-1 * %n) + ((%n + %x) smax %n))
; CHECK-NEXT: Loop %do.body: max backedge-taken count is -1{{$}}

do.end:
  ret void
}

define void @s32_max2_unpredictable_exit(i32 %n, i32 %x, i32* %p) {
entry:
  %add = add i32 %n, 2
  br label %do.body

do.body:
  %i.0 = phi i32 [ %n, %entry ], [ %inc, %if.end ]
  %cmp = icmp eq i32 %i.0, %x
  br i1 %cmp, label %do.end, label %if.end ; unpredictable

if.end:
  %arrayidx = getelementptr i32, i32* %p, i32 %i.0
  store i32 %i.0, i32* %arrayidx, align 4
  %inc = add i32 %i.0, 1
  %cmp1 = icmp slt i32 %i.0, %add
  br i1 %cmp1, label %do.body, label %do.end ; taken either 0 or 2 times

; CHECK-LABEL: Determining loop execution counts for: @s32_max2_unpredictable_exit
; CHECK-NEXT: Loop %do.body: <multiple exits> backedge-taken count is (((-1 * %n) + ((2 + %n) smax %n)) umin ((-1 * %n) + %x))
; CHECK-NEXT:   exit count for do.body: ((-1 * %n) + %x)
; CHECK-NEXT:   exit count for if.end: ((-1 * %n) + ((2 + %n) smax %n))
; CHECK-NEXT: Loop %do.body: max backedge-taken count is 2{{$}}

do.end:
  ret void
}

define void @u32_max1(i32 %n, i32* %p) {
entry:
  %add = add i32 %n, 1
  br label %do.body

do.body:
  %i.0 = phi i32 [ %n, %entry ], [ %inc, %do.body ]
  %arrayidx = getelementptr i32, i32* %p, i32 %i.0
  store i32 %i.0, i32* %arrayidx, align 4
  %inc = add i32 %i.0, 1
  %cmp = icmp ult i32 %i.0, %add
  br i1 %cmp, label %do.body, label %do.end ; taken either 0 or 1 times

; CHECK-LABEL: Determining loop execution counts for: @u32_max1
; CHECK-NEXT: Loop %do.body: backedge-taken count is ((-1 * %n) + ((1 + %n) umax %n))
; CHECK-NEXT: Loop %do.body: max backedge-taken count is 1, actual taken count either this or zero.

do.end:
  ret void
}

define void @u32_max2(i32 %n, i32* %p) {
entry:
  %add = add i32 %n, 2
  br label %do.body

do.body:
  %i.0 = phi i32 [ %n, %entry ], [ %inc, %do.body ]
  %arrayidx = getelementptr i32, i32* %p, i32 %i.0
  store i32 %i.0, i32* %arrayidx, align 4
  %inc = add i32 %i.0, 1
  %cmp = icmp ult i32 %i.0, %add
  br i1 %cmp, label %do.body, label %do.end ; taken either 0 or 2 times

; CHECK-LABEL: Determining loop execution counts for: @u32_max2
; CHECK-NEXT: Loop %do.body: backedge-taken count is ((-1 * %n) + ((2 + %n) umax %n))
; CHECK-NEXT: Loop %do.body: max backedge-taken count is 2, actual taken count either this or zero.

do.end:
  ret void
}

define void @u32_maxx(i32 %n, i32 %x, i32* %p) {
entry:
  %add = add i32 %x, %n
  br label %do.body

do.body:
  %i.0 = phi i32 [ %n, %entry ], [ %inc, %do.body ]
  %arrayidx = getelementptr i32, i32* %p, i32 %i.0
  store i32 %i.0, i32* %arrayidx, align 4
  %inc = add i32 %i.0, 1
  %cmp = icmp ult i32 %i.0, %add
  br i1 %cmp, label %do.body, label %do.end ; taken either 0 or x times

; CHECK-LABEL: Determining loop execution counts for: @u32_maxx
; CHECK-NEXT: Loop %do.body: backedge-taken count is ((-1 * %n) + ((%n + %x) umax %n))
; CHECK-NEXT: Loop %do.body: max backedge-taken count is -1{{$}}

do.end:
  ret void
}

define void @u32_max2_unpredictable_exit(i32 %n, i32 %x, i32* %p) {
entry:
  %add = add i32 %n, 2
  br label %do.body

do.body:
  %i.0 = phi i32 [ %n, %entry ], [ %inc, %if.end ]
  %cmp = icmp eq i32 %i.0, %x
  br i1 %cmp, label %do.end, label %if.end ; unpredictable

if.end:
  %arrayidx = getelementptr i32, i32* %p, i32 %i.0
  store i32 %i.0, i32* %arrayidx, align 4
  %inc = add i32 %i.0, 1
  %cmp1 = icmp ult i32 %i.0, %add
  br i1 %cmp1, label %do.body, label %do.end ; taken either 0 or 2 times

; CHECK-LABEL: Determining loop execution counts for: @u32_max2_unpredictable_exit
; CHECK-NEXT: Loop %do.body: <multiple exits> backedge-taken count is (((-1 * %n) + ((2 + %n) umax %n)) umin ((-1 * %n) + %x))
; CHECK-NEXT:   exit count for do.body: ((-1 * %n) + %x)
; CHECK-NEXT:   exit count for if.end: ((-1 * %n) + ((2 + %n) umax %n))
; CHECK-NEXT: Loop %do.body: max backedge-taken count is 2{{$}}

do.end:
  ret void
}