llvm/test/Analysis/DependenceAnalysis/symbolic-rdiv-overflow.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
; RUN: opt < %s -disable-output "-passes=print<da>" -da-enable-dependence-test=symbolic-rdiv 2>&1 \
; RUN:     | FileCheck %s --check-prefixes=CHECK,CHECK-SYMBOLIC-RDIV

; for (i = 0; i < (1LL << 62); i++) {
;   if (0 <= 2*i - 2)
;     A[2*i - 2] = 1;
;   A[i] = 2;
; }
;
; FIXME: DependenceAnalysis currently detects no dependency between the two
; stores, but it does exist. For example, each store will access A[0] when i
; is 1 and 0 respectively.
; The root cause is that the product of the BTC and the coefficient
; ((1LL << 62) - 1 and 2) overflows in a signed sense.
define void @symbolicrdiv_prod_ovfl(ptr %A) {
; CHECK-ALL-LABEL: 'symbolicrdiv_prod_ovfl'
; CHECK-ALL-NEXT:  Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 1, ptr %gep.0, align 1
; CHECK-ALL-NEXT:    da analyze - none!
; CHECK-ALL-NEXT:  Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-ALL-NEXT:    da analyze - none!
; CHECK-ALL-NEXT:  Src: store i8 2, ptr %gep.1, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-ALL-NEXT:    da analyze - none!
;
; CHECK-SYMBOLIC-RDIV-LABEL: 'symbolicrdiv_prod_ovfl'
; CHECK-SYMBOLIC-RDIV-NEXT:  Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 1, ptr %gep.0, align 1
; CHECK-SYMBOLIC-RDIV-NEXT:    da analyze - none!
; CHECK-SYMBOLIC-RDIV-NEXT:  Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-SYMBOLIC-RDIV-NEXT:    da analyze - none!
; CHECK-SYMBOLIC-RDIV-NEXT:  Src: store i8 2, ptr %gep.1, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-SYMBOLIC-RDIV-NEXT:    da analyze - consistent output [*]!
;
entry:
  br label %loop.header

loop.header:
  %i = phi i64 [ 0, %entry ], [ %i.inc, %loop.latch ]
  %offset = phi i64 [ -2, %entry ], [ %offset.next, %loop.latch ]
  %ec = icmp eq i64 %i, 4611686018427387904
  br i1 %ec, label %exit, label %loop.body

loop.body:
  %cond = icmp sge i64 %offset, 0
  br i1 %cond, label %if.then, label %loop.latch

if.then:
  %gep.0 = getelementptr inbounds i8, ptr %A, i64 %offset
  store i8 1, ptr %gep.0
  br label %loop.latch

loop.latch:
  %gep.1 = getelementptr inbounds i8, ptr %A, i64 %i
  store i8 2, ptr %gep.1
  %i.inc = add nuw nsw i64 %i, 1
  %offset.next = add nsw i64 %offset, 2
  br label %loop.header

exit:
  ret void
}

; offset0 = -4611686018427387904;  // -2^62
; offset1 =  4611686018427387904;  // 2^62
; for (i = 0; i < (1LL << 62) - 100; i++) {
;   if (0 <= offset0)
;     A[offset0] = 1;
;   if (0 <= offset1)
;     A[offset1] = 2;
;   offset0 += 2;
;   offset1 -= 1;
; }
;
; FIXME: DependenceAnalysis currently detects no dependency between the two
; stores, but it does exist. For example,
;
;  memory access           | i == 2^61 | i == 2^61 + 2^59 | i == 2^61 + 2^60
; -------------------------|-----------|------------------|-------------------
;  A[2*i - 2^62] (offset0) |           | A[2^60]          | A[2^61]
;  A[-i + 2^62]  (offset1) | A[2^61]   |                  | A[2^60]
;
; The root cause is that the calculation of the differenct between the two
; constants (-2^62 and 2^62) overflows in a signed sense.
define void @symbolicrdiv_delta_ovfl(ptr %A) {
; CHECK-ALL-LABEL: 'symbolicrdiv_delta_ovfl'
; CHECK-ALL-NEXT:  Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 1, ptr %gep.0, align 1
; CHECK-ALL-NEXT:    da analyze - none!
; CHECK-ALL-NEXT:  Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-ALL-NEXT:    da analyze - none!
; CHECK-ALL-NEXT:  Src: store i8 2, ptr %gep.1, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-ALL-NEXT:    da analyze - none!
;
; CHECK-SYMBOLIC-RDIV-LABEL: 'symbolicrdiv_delta_ovfl'
; CHECK-SYMBOLIC-RDIV-NEXT:  Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 1, ptr %gep.0, align 1
; CHECK-SYMBOLIC-RDIV-NEXT:    da analyze - consistent output [*]!
; CHECK-SYMBOLIC-RDIV-NEXT:  Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-SYMBOLIC-RDIV-NEXT:    da analyze - none!
; CHECK-SYMBOLIC-RDIV-NEXT:  Src: store i8 2, ptr %gep.1, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-SYMBOLIC-RDIV-NEXT:    da analyze - consistent output [*]!
;
entry:
  br label %loop.header

loop.header:
  %i = phi i64 [ 0, %entry ], [ %i.inc, %loop.latch ]
  %offset.0 = phi i64 [ -4611686018427387904, %entry ], [ %offset.0.next, %loop.latch ]
  %offset.1 = phi i64 [ 4611686018427387904, %entry ], [ %offset.1.next, %loop.latch ]
  %cond.0 = icmp sge i64 %offset.0, 0
  %cond.1 = icmp sge i64 %offset.1, 0
  br i1 %cond.0, label %if.then.0, label %loop.middle

if.then.0:
  %gep.0 = getelementptr inbounds i8, ptr %A, i64 %offset.0
  store i8 1, ptr %gep.0
  br label %loop.middle

loop.middle:
  br i1 %cond.1, label %if.then.1, label %loop.latch

if.then.1:
  %gep.1 = getelementptr inbounds i8, ptr %A, i64 %offset.1
  store i8 2, ptr %gep.1
  br label %loop.latch

loop.latch:
  %i.inc = add nuw nsw i64 %i, 1
  %offset.0.next = add nsw i64 %offset.0, 2
  %offset.1.next = sub nsw i64 %offset.1, 1
  %ec = icmp eq i64 %i.inc, 4611686018427387804 ; 2^62 - 100
  br i1 %ec, label %exit, label %loop.header

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