llvm/test/Transforms/LoopInstSimplify/basic.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -S %s -passes=loop-instsimplify | FileCheck %s
; RUN: opt -S %s -passes=loop-instsimplify -enable-mssa-loop-dependency=true -verify-memoryssa | FileCheck %s

; Test very basic folding and propagation occurs within a loop body. This should
; collapse to the loop iteration structure and the LCSSA PHI node.
define i32 @test1(i32 %n, i32 %x) {
; CHECK-LABEL: @test1(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[I_NEXT:%.*]], [[LOOP]] ]
; CHECK-NEXT:    [[I_NEXT]] = add nsw i32 [[I]], 1
; CHECK-NEXT:    [[I_CMP:%.*]] = icmp slt i32 [[I_NEXT]], [[N:%.*]]
; CHECK-NEXT:    br i1 [[I_CMP]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    [[X_LCSSA:%.*]] = phi i32 [ [[X:%.*]], [[LOOP]] ]
; CHECK-NEXT:    ret i32 [[X_LCSSA]]
;
entry:
  br label %loop

loop:
  %i = phi i32 [ 0, %entry ], [ %i.next, %loop ]
  %x.add = add nsw i32 %x, 0
  %x.sub = sub i32 %x.add, 0
  %x.and = and i32 %x.sub, -1
  %i.next = add nsw i32 %i, 1
  %i.cmp = icmp slt i32 %i.next, %n
  br i1 %i.cmp, label %loop, label %exit

exit:
  %x.lcssa = phi i32 [ %x.and, %loop ]
  ret i32 %x.lcssa
}

; Test basic loop structure that still has a simplification feed a prior PHI.
define i32 @test2(i32 %n, i32 %x) {
; CHECK-LABEL: @test2(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[I_NEXT:%.*]], [[LOOP]] ]
; CHECK-NEXT:    [[I_NEXT]] = add nsw i32 [[I]], 1
; CHECK-NEXT:    [[I_CMP:%.*]] = icmp slt i32 [[I_NEXT]], [[N:%.*]]
; CHECK-NEXT:    br i1 [[I_CMP]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    [[X_LCSSA:%.*]] = phi i32 [ [[X:%.*]], [[LOOP]] ]
; CHECK-NEXT:    ret i32 [[X_LCSSA]]
;
entry:
  br label %loop

loop:
  %i = phi i32 [ 0, %entry ], [ %i.next, %loop ]
  %x.loop = phi i32 [ %x, %entry ], [ %x.next, %loop ]
  %x.next = add nsw i32 %x.loop, 0
  %i.next = add nsw i32 %i, 1
  %i.cmp = icmp slt i32 %i.next, %n
  br i1 %i.cmp, label %loop, label %exit

exit:
  %x.lcssa = phi i32 [ %x.loop, %loop ]
  ret i32 %x.lcssa
}

; Test a diamond CFG with inner PHI nodes.
define i32 @test3(i32 %n, i32 %x) {
; CHECK-LABEL: @test3(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[I_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
; CHECK-NEXT:    [[X_CMP:%.*]] = icmp slt i32 [[I]], 42
; CHECK-NEXT:    br i1 [[X_CMP]], label [[LOOP_LHS:%.*]], label [[LOOP_RHS:%.*]]
; CHECK:       loop.lhs:
; CHECK-NEXT:    br label [[LOOP_LATCH]]
; CHECK:       loop.rhs:
; CHECK-NEXT:    br label [[LOOP_LATCH]]
; CHECK:       loop.latch:
; CHECK-NEXT:    [[I_NEXT]] = add nsw i32 [[I]], 1
; CHECK-NEXT:    [[I_CMP:%.*]] = icmp slt i32 [[I_NEXT]], [[N:%.*]]
; CHECK-NEXT:    br i1 [[I_CMP]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    [[X_LCSSA:%.*]] = phi i32 [ [[X:%.*]], [[LOOP_LATCH]] ]
; CHECK-NEXT:    ret i32 [[X_LCSSA]]
;
entry:
  br label %loop

loop:
  %i = phi i32 [ 0, %entry ], [ %i.next, %loop.latch ]
  %x.loop = phi i32 [ %x, %entry ], [ %x.phi, %loop.latch ]
  %x.add = add nsw i32 %x.loop, 0
  %x.cmp = icmp slt i32 %i, 42
  br i1 %x.cmp, label %loop.lhs, label %loop.rhs

loop.lhs:
  %x.l.add = add nsw i32 %x.add, 0
  br label %loop.latch

loop.rhs:
  %x.r.sub = sub nsw i32 %x.add, 0
  br label %loop.latch

loop.latch:
  %x.phi = phi i32 [ %x.l.add, %loop.lhs ], [ %x.r.sub, %loop.rhs ]
  %i.next = add nsw i32 %i, 1
  %i.cmp = icmp slt i32 %i.next, %n
  br i1 %i.cmp, label %loop, label %exit

exit:
  %x.lcssa = phi i32 [ %x.loop, %loop.latch ]
  ret i32 %x.lcssa
}

; Test an inner loop that is only simplified when processing the outer loop, and
; an outer loop only simplified when processing the inner loop.
define i32 @test4(i32 %n, i32 %m, i32 %x) {
; CHECK-LABEL: @test4(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[I_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
; CHECK-NEXT:    br label [[LOOP_INNER:%.*]]
; CHECK:       loop.inner:
; CHECK-NEXT:    [[J:%.*]] = phi i32 [ 0, [[LOOP]] ], [ [[J_NEXT:%.*]], [[LOOP_INNER]] ]
; CHECK-NEXT:    [[J_NEXT]] = add nsw i32 [[J]], 1
; CHECK-NEXT:    [[J_CMP:%.*]] = icmp slt i32 [[J_NEXT]], [[M:%.*]]
; CHECK-NEXT:    br i1 [[J_CMP]], label [[LOOP_INNER]], label [[LOOP_LATCH]]
; CHECK:       loop.latch:
; CHECK-NEXT:    [[I_NEXT]] = add nsw i32 [[I]], 1
; CHECK-NEXT:    [[I_CMP:%.*]] = icmp slt i32 [[I_NEXT]], [[N:%.*]]
; CHECK-NEXT:    br i1 [[I_CMP]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    [[X_LCSSA:%.*]] = phi i32 [ [[X:%.*]], [[LOOP_LATCH]] ]
; CHECK-NEXT:    ret i32 [[X_LCSSA]]
;
entry:
  br label %loop

loop:
  %i = phi i32 [ 0, %entry ], [ %i.next, %loop.latch ]
  %x.loop = phi i32 [ %x, %entry ], [ %x.inner.lcssa, %loop.latch ]
  %x.add = add nsw i32 %x.loop, 0
  br label %loop.inner

loop.inner:
  %j = phi i32 [ 0, %loop ], [ %j.next, %loop.inner ]
  %x.inner.loop = phi i32 [ %x.add, %loop ], [ %x.inner.add, %loop.inner ]
  %x.inner.add = add nsw i32 %x.inner.loop, 0
  %j.next = add nsw i32 %j, 1
  %j.cmp = icmp slt i32 %j.next, %m
  br i1 %j.cmp, label %loop.inner, label %loop.latch

loop.latch:
  %x.inner.lcssa = phi i32 [ %x.inner.loop, %loop.inner ]
  %i.next = add nsw i32 %i, 1
  %i.cmp = icmp slt i32 %i.next, %n
  br i1 %i.cmp, label %loop, label %exit

exit:
  %x.lcssa = phi i32 [ %x.loop, %loop.latch ]
  ret i32 %x.lcssa
}