llvm/test/Transforms/LoopInterchange/lcssa-phi-outer-latch.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
; RUN: opt < %s -passes=loop-interchange -cache-line-size=64 -verify-dom-info -verify-loop-info -verify-scev -verify-loop-lcssa -S | FileCheck %s

; This test is checking that blocks outer.body and outer.latch, where outer.body is the exit
; block of the inner loop and outer.latch the latch of the outer loop, correctly
; deal with the phi-node use-def chain %new.cond.lcssa -> %old.cond.lcssa. What we expect
; here is that block outer.latch does not contain a phi node, because it is a single input
; phi in a non-exit block.

target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"

define i16 @main(ptr %a) {
; CHECK-LABEL: define i16 @main(
; CHECK-SAME: ptr [[A:%.*]]) {
; CHECK-NEXT:  [[ENTRY:.*:]]
; CHECK-NEXT:    br label %[[INNER_HEADER_PREHEADER:.*]]
; CHECK:       [[OUTER_HEADER_PREHEADER:.*]]:
; CHECK-NEXT:    br label %[[OUTER_HEADER:.*]]
; CHECK:       [[OUTER_HEADER]]:
; CHECK-NEXT:    [[I:%.*]] = phi i64 [ [[I_NEXT:%.*]], %[[OUTER_LATCH:.*]] ], [ 1, %[[OUTER_HEADER_PREHEADER]] ]
; CHECK-NEXT:    br label %[[INNER_HEADER_SPLIT:.*]]
; CHECK:       [[INNER_HEADER_PREHEADER]]:
; CHECK-NEXT:    br label %[[INNER_HEADER:.*]]
; CHECK:       [[INNER_HEADER]]:
; CHECK-NEXT:    [[J:%.*]] = phi i16 [ [[TMP1:%.*]], %[[INNER_LATCH_SPLIT:.*]] ], [ 0, %[[INNER_HEADER_PREHEADER]] ]
; CHECK-NEXT:    br label %[[OUTER_HEADER_PREHEADER]]
; CHECK:       [[INNER_HEADER_SPLIT]]:
; CHECK-NEXT:    [[ARRAYIDX_US_US:%.*]] = getelementptr i16, ptr [[A]], i16 [[J]]
; CHECK-NEXT:    [[TMP0:%.*]] = load i16, ptr [[ARRAYIDX_US_US]], align 1
; CHECK-NEXT:    [[COND:%.*]] = select i1 false, i16 0, i16 0
; CHECK-NEXT:    br label %[[INNER_LATCH:.*]]
; CHECK:       [[INNER_LATCH]]:
; CHECK-NEXT:    [[J_NEXT:%.*]] = add i16 [[J]], 1
; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i16 [[J]], 42
; CHECK-NEXT:    br label %[[OUTER_BODY:.*]]
; CHECK:       [[INNER_LATCH_SPLIT]]:
; CHECK-NEXT:    [[NEW_COND_LCSSA:%.*]] = phi i16 [ [[COND]], %[[OUTER_LATCH]] ]
; CHECK-NEXT:    [[TMP1]] = add i16 [[J]], 1
; CHECK-NEXT:    [[TMP2:%.*]] = icmp slt i16 [[J]], 42
; CHECK-NEXT:    br i1 [[TMP2]], label %[[INNER_HEADER]], label %[[EXIT:.*]]
; CHECK:       [[OUTER_BODY]]:
; CHECK-NEXT:    br label %[[OUTER_LATCH]]
; CHECK:       [[OUTER_LATCH]]:
; CHECK-NEXT:    [[I_NEXT]] = add i64 [[I]], 1
; CHECK-NEXT:    [[CMP286_US:%.*]] = icmp ugt i64 [[I]], 0
; CHECK-NEXT:    br i1 [[CMP286_US]], label %[[OUTER_HEADER]], label %[[INNER_LATCH_SPLIT]]
; CHECK:       [[EXIT]]:
; CHECK-NEXT:    [[OLD_COND_LCSSA_LCSSA:%.*]] = phi i16 [ [[NEW_COND_LCSSA]], %[[INNER_LATCH_SPLIT]] ]
; CHECK-NEXT:    ret i16 [[OLD_COND_LCSSA_LCSSA]]
;
entry:
  br label %outer.header

outer.header:
  %i = phi i64 [ 1, %entry ], [ %i.next, %outer.latch ]
  br label %inner.header

inner.header:
  %j = phi i16 [ 0, %outer.header ], [ %j.next, %inner.latch ]
  %arrayidx.us.us = getelementptr i16, ptr %a, i16 %j
  %0 = load i16, ptr %arrayidx.us.us, align 1
  %cond = select i1 false, i16 0, i16 0
  br label %inner.latch

inner.latch:
  %j.next = add i16 %j, 1
  %cmp = icmp slt i16 %j, 42
  br i1 %cmp, label %inner.header, label %outer.body

outer.body:
  %new.cond.lcssa = phi i16 [ %cond, %inner.latch ]
  br label %outer.latch

outer.latch:
  %old.cond.lcssa = phi i16 [ %new.cond.lcssa, %outer.body ]
  %i.next = add i64 %i, 1
  %cmp286.us = icmp ugt i64 %i, 0
  br i1 %cmp286.us, label %outer.header, label %exit

exit:
  ret i16 %old.cond.lcssa
}