llvm/test/Transforms/LoopInterchange/inner-preheader-multi-entry-phi.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
; RUN: opt -passes=loop-interchange -loop-interchange-profitabilities=ignore \
; RUN:   -verify-dom-info -verify-loop-info -verify-loop-lcssa -S %s \
; RUN:   | FileCheck %s

; The outer header branches to the inner preheader via duplicate edges, giving
; the preheader a PHI with two identical incoming entries. Interchange must
; succeed: both entries carry the same value so the PHI can be safely removed.

define void @multi_entry_phi(ptr noalias %A, i1 %c) {
; CHECK-LABEL: define void @multi_entry_phi(
; CHECK-SAME: ptr noalias [[A:%.*]], i1 [[C:%.*]]) {
; CHECK-NEXT:  [[ENTRY:.*:]]
; CHECK-NEXT:    br label %[[INNER_PH:.*]]
; CHECK:       [[OUTER_HEADER_PREHEADER:.*]]:
; CHECK-NEXT:    br label %[[OUTER_HEADER:.*]]
; CHECK:       [[OUTER_HEADER]]:
; CHECK-NEXT:    [[I:%.*]] = phi i64 [ [[I_INC:%.*]], %[[OUTER_LATCH:.*]] ], [ 0, %[[OUTER_HEADER_PREHEADER]] ]
; CHECK-NEXT:    br i1 [[C]], label %[[INNER_SPLIT1:.*]], label %[[INNER_SPLIT1]]
; CHECK:       [[INNER_PH]]:
; CHECK-NEXT:    br label %[[INNER:.*]]
; CHECK:       [[INNER]]:
; CHECK-NEXT:    [[J:%.*]] = phi i64 [ 0, %[[INNER_PH]] ], [ [[TMP0:%.*]], %[[INNER_SPLIT:.*]] ]
; CHECK-NEXT:    br label %[[OUTER_HEADER_PREHEADER]]
; CHECK:       [[INNER_SPLIT1]]:
; CHECK-NEXT:    [[IDX:%.*]] = mul i64 [[J]], 10
; CHECK-NEXT:    [[OFF:%.*]] = add i64 [[IDX]], [[I]]
; CHECK-NEXT:    [[GEP:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[OFF]]
; CHECK-NEXT:    store i32 0, ptr [[GEP]], align 4
; CHECK-NEXT:    [[J_INC:%.*]] = add i64 [[J]], 1
; CHECK-NEXT:    [[EC_J:%.*]] = icmp eq i64 [[J_INC]], 10
; CHECK-NEXT:    br label %[[OUTER_LATCH]]
; CHECK:       [[INNER_SPLIT]]:
; CHECK-NEXT:    [[TMP0]] = add i64 [[J]], 1
; CHECK-NEXT:    [[TMP1:%.*]] = icmp eq i64 [[TMP0]], 10
; CHECK-NEXT:    br i1 [[TMP1]], label %[[EXIT:.*]], label %[[INNER]]
; CHECK:       [[OUTER_LATCH]]:
; CHECK-NEXT:    [[I_INC]] = add i64 [[I]], 1
; CHECK-NEXT:    [[EC_I:%.*]] = icmp eq i64 [[I_INC]], 10
; CHECK-NEXT:    br i1 [[EC_I]], label %[[INNER_SPLIT]], label %[[OUTER_HEADER]]
; CHECK:       [[EXIT]]:
; CHECK-NEXT:    ret void
;
entry:
  br label %outer.header

outer.header:
  %i = phi i64 [ 0, %entry ], [ %i.inc, %outer.latch ]
  br i1 %c, label %inner.ph, label %inner.ph

inner.ph:
  %p = phi i64 [ 42, %outer.header ], [ 42, %outer.header ]
  br label %inner

inner:
  %j = phi i64 [ 0, %inner.ph ], [ %j.inc, %inner ]
  %idx = mul i64 %j, 10
  %off = add i64 %idx, %i
  %gep = getelementptr inbounds i32, ptr %A, i64 %off
  store i32 0, ptr %gep, align 4
  %j.inc = add i64 %j, 1
  %ec.j = icmp eq i64 %j.inc, 10
  br i1 %ec.j, label %outer.latch, label %inner

outer.latch:
  %i.inc = add i64 %i, 1
  %ec.i = icmp eq i64 %i.inc, 10
  br i1 %ec.i, label %exit, label %outer.header

exit:
  ret void
}