test/Analysis/DependenceAnalysis/rdiv-minor-algebra.ll

; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 6
; RUN: opt < %s -disable-output "-passes=print<da>" 2>&1 \
; RUN:     | FileCheck %s --check-prefixes=CHECK,CHECK-ALL
;
; for (i = 0; i < 2; i++) {
;   A[-2] = 0;
;   for (j = 0; j < 2; j++) {
;     if (i == j)
;       A[INT64_MAX*i + INT64_MAX*j] = 1;
;   }
; }
;
; There is a dependency between the two stores.
;
;  memory access                | (i, j) == (1, 1)
; ------------------------------|------------------
;  A[-2]                        | A[-2]
;  A[INT64_MAX*i + INT64_MAX*j] | A[-2]
;
; Previously, this dependency was missed because RDIV performs "minor algebra"
; and transforms the subscripts as follows:
;
;   A[-2] and A[INT64_MAX*i + INT64_MAX*j]
;
;    | minor algebra
;    v
;
;   A[-INT64_MAX*j - 2] and A[INT64_MAX*i]
;
; This is unsound.
;
define void @f(ptr %A) {
; CHECK-LABEL: 'f'
; CHECK-NEXT:  Src: store i8 0, ptr %gep.0, align 1 --> Dst: store i8 0, ptr %gep.0, align 1
; CHECK-NEXT:    da analyze - output [S]!
; CHECK-NEXT:  Src: store i8 0, ptr %gep.0, align 1 --> Dst: store i8 1, ptr %gep.1, align 1
; CHECK-NEXT:    da analyze - output [*|<]!
; CHECK-NEXT:  Src: store i8 1, ptr %gep.1, align 1 --> Dst: store i8 1, ptr %gep.1, align 1
; CHECK-NEXT:    da analyze - output [* *]!
;
entry:
  br label %loop.i.header

loop.i.header:
  %i = phi i64 [ 0, %entry ], [ %i.inc, %loop.i.latch ]
  %i.mul = mul i64 %i, 9223372036854775807
  %gep.0 = getelementptr i8, ptr %A, i64 -2
  store i8 0, ptr %gep.0
  br label %loop.j.header

loop.j.header:
  %j = phi i64 [ 0, %loop.i.header ], [ %j.inc, %loop.j.latch ]
  %j.mul = mul i64 %j, 9223372036854775807
  %offset.tmp = add i64 %i.mul, %j.mul
  %offset = add i64 %offset.tmp, -2
  %cond = icmp eq i64 %i, %j
  br i1 %cond, label %if.then, label %loop.j.latch

if.then:
  %gep.1 = getelementptr i8, ptr %A, i64 %offset
  store i8 1, ptr %gep.1
  br label %loop.j.latch

loop.j.latch:
  %j.inc = add i64 %j, 1
  %ec.j = icmp eq i64 %j.inc, 2
  br i1 %ec.j, label %loop.i.latch, label %loop.j.header

loop.i.latch:
  %i.inc = add i64 %i, 1
  %ec.i = icmp eq i64 %i.inc, 2
  br i1 %ec.i, label %exit, label %loop.i.header

exit:
  ret void
}
;; NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line:
; CHECK-ALL: {{.*}}