llvm/test/Analysis/DependenceAnalysis/gcd-miv-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=gcd-miv 2>&1 \
; RUN:     | FileCheck %s --check-prefixes=CHECK,CHECK-GCD-MIV

; offset0 = 4;
; offset1 = 0;
; for (i = 0; i < 100; i++) {
;   A[offset0] = 1;
;   A[offset1] = 2;
;   offset0 += 3*m;
;   offset1 += 3;
; }
;
; Dependency exists between the two stores. E.g., consider `m` is
; 12297829382473034411, which is a modular multiplicative inverse of 3 under
; modulo 2^64. Then `offset0` is effectively `i + 4`, so accesses will be as
; follows:
;
;   - A[offset0] : A[4], A[5], A[6], ...
;   - A[offset1] : A[0], A[3], A[6], ...
;
define void @gcdmiv_coef_ovfl(ptr %A, i64 %m) {
; CHECK-ALL-LABEL: 'gcdmiv_coef_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 - consistent output [0]!
; CHECK-ALL-NEXT:    Runtime Assumptions:
; CHECK-ALL-NEXT:    Compare predicate: (3 * %m) ne) 0
; 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 - output [*|<]!
; 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-GCD-MIV-LABEL: 'gcdmiv_coef_ovfl'
; CHECK-GCD-MIV-NEXT:  Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 1, ptr %gep.0, align 1
; CHECK-GCD-MIV-NEXT:    da analyze - consistent output [*]!
; CHECK-GCD-MIV-NEXT:  Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-GCD-MIV-NEXT:    da analyze - consistent output [*|<]!
; CHECK-GCD-MIV-NEXT:  Src: store i8 2, ptr %gep.1, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-GCD-MIV-NEXT:    da analyze - consistent output [*]!
;
entry:
  %step = mul i64 3, %m
  br label %loop

loop:
  %i = phi i64 [ 0, %entry ], [ %i.inc, %loop ]
  %offset.0 = phi i64 [ 4, %entry ] , [ %offset.0.next, %loop ]
  %offset.1 = phi i64 [ 0, %entry ] , [ %offset.1.next, %loop ]
  %gep.0 = getelementptr inbounds i8, ptr %A, i64 %offset.0
  %gep.1 = getelementptr inbounds i8, ptr %A, i64 %offset.1
  store i8 1, ptr %gep.0
  store i8 2, ptr %gep.1
  %i.inc = add nuw nsw i64 %i, 1
  %offset.0.next = add nsw i64 %offset.0, %step
  %offset.1.next = add nsw i64 %offset.1, 3
  %ec = icmp eq i64 %i.inc, 100
  br i1 %ec, label %exit, label %loop

exit:
  ret void
}

; max_i = INT64_MAX/6  // 1537228672809129301
; for (long long i = 0; i <= max_i; i++) {
;   A[-6*i + INT64_MAX] = 0;
;   if (i)
;     A[3*i - 2] = 1;
; }
;
; FIXME: DependenceAnalysis currently detects no dependency between the two
; stores, but it does exist. For example,
;
;  memory access       | i == 1 | i == (max_i + 1) / 2 | i == max_i
; ---------------------|--------|----------------------|-------------------
;  A[-6*i + INT64_MAX] |        | A[3*max_i - 2]       | A[1]
;  A[3*i - 2]          | A[1]   |                      | A[3*max_i - 2]
;
;
define void @gcdmiv_delta_ovfl(ptr %A) {
; CHECK-ALL-LABEL: 'gcdmiv_delta_ovfl'
; CHECK-ALL-NEXT:  Src: store i8 0, ptr %idx.0, align 1 --> Dst: store i8 0, ptr %idx.0, align 1
; CHECK-ALL-NEXT:    da analyze - none!
; CHECK-ALL-NEXT:  Src: store i8 0, ptr %idx.0, align 1 --> Dst: store i8 1, ptr %idx.1, align 1
; CHECK-ALL-NEXT:    da analyze - none!
; CHECK-ALL-NEXT:  Src: store i8 1, ptr %idx.1, align 1 --> Dst: store i8 1, ptr %idx.1, align 1
; CHECK-ALL-NEXT:    da analyze - none!
;
; CHECK-GCD-MIV-LABEL: 'gcdmiv_delta_ovfl'
; CHECK-GCD-MIV-NEXT:  Src: store i8 0, ptr %idx.0, align 1 --> Dst: store i8 0, ptr %idx.0, align 1
; CHECK-GCD-MIV-NEXT:    da analyze - consistent output [*]!
; CHECK-GCD-MIV-NEXT:  Src: store i8 0, ptr %idx.0, align 1 --> Dst: store i8 1, ptr %idx.1, align 1
; CHECK-GCD-MIV-NEXT:    da analyze - consistent output [*|<]!
; CHECK-GCD-MIV-NEXT:  Src: store i8 1, ptr %idx.1, align 1 --> Dst: store i8 1, ptr %idx.1, align 1
; CHECK-GCD-MIV-NEXT:    da analyze - consistent output [*]!
;
entry:
  br label %loop.header

loop.header:
  %i = phi i64 [ 0, %entry ], [ %i.inc, %loop.latch ]
  %subscript.0 = phi i64 [ 9223372036854775807, %entry ], [ %subscript.0.next, %loop.latch ]
  %subscript.1 = phi i64 [ -2, %entry ], [ %subscript.1.next, %loop.latch ]
  %idx.0 = getelementptr inbounds i8, ptr %A, i64 %subscript.0
  store i8 0, ptr %idx.0
  %cond.store = icmp ne i64 %i, 0
  br i1 %cond.store, label %if.store, label %loop.latch

if.store:
  %idx.1 = getelementptr i8, ptr %A, i64 %subscript.1
  store i8 1, ptr %idx.1
  br label %loop.latch

loop.latch:
  %i.inc = add nuw nsw i64 %i, 1
  %subscript.0.next = add nsw i64 %subscript.0, -6
  %subscript.1.next = add nsw i64 %subscript.1, 3
  %exitcond = icmp sgt i64 %i.inc, 1537228672809129301
  br i1 %exitcond, label %exit, label %loop.header

exit:
  ret void
}

; max_i = INT64_MAX/3  // 3074457345618258602
; for (i = 0; i < max_i; i++) {
;   A[3*i] = 0;
;   A[-3*i - 3*m - INT64_MAX] = 1;
; }
;
; Dependency may exist between the two stores. For example, consider `m = 1`.
; Then, `-3*m - INT64_MAX` is `INT64_MAX - 1`. So `-3*i - 3*m - INT64_MAX` is
; effectively `-3*i + (INT64_MAX - 1)`. Thus, accesses will be as follows:
;
;  memory access             | i == 1           | i == max_i - 1
; ---------------------------|------------------|------------------
;  A[3*i]                    | A[3]             | A[INT64_MAX - 4]
;  A[-3*i - 3*m - INT64_MAX] | A[INT64_MAX - 4] | A[3]
;

define void @gcdmiv_const_ovfl(ptr %A, i64 %m) {
; CHECK-ALL-LABEL: 'gcdmiv_const_ovfl'
; CHECK-ALL-NEXT:  Src: store i8 0, ptr %gep.0, align 1 --> Dst: store i8 0, ptr %gep.0, align 1
; CHECK-ALL-NEXT:    da analyze - none!
; CHECK-ALL-NEXT:  Src: store i8 0, ptr %gep.0, align 1 --> Dst: store i8 1, ptr %gep.1, align 1
; CHECK-ALL-NEXT:    da analyze - output [*|<]!
; CHECK-ALL-NEXT:  Src: store i8 1, ptr %gep.1, align 1 --> Dst: store i8 1, ptr %gep.1, align 1
; CHECK-ALL-NEXT:    da analyze - none!
;
; CHECK-GCD-MIV-LABEL: 'gcdmiv_const_ovfl'
; CHECK-GCD-MIV-NEXT:  Src: store i8 0, ptr %gep.0, align 1 --> Dst: store i8 0, ptr %gep.0, align 1
; CHECK-GCD-MIV-NEXT:    da analyze - consistent output [*]!
; CHECK-GCD-MIV-NEXT:  Src: store i8 0, ptr %gep.0, align 1 --> Dst: store i8 1, ptr %gep.1, align 1
; CHECK-GCD-MIV-NEXT:    da analyze - consistent output [*|<]!
; CHECK-GCD-MIV-NEXT:  Src: store i8 1, ptr %gep.1, align 1 --> Dst: store i8 1, ptr %gep.1, align 1
; CHECK-GCD-MIV-NEXT:    da analyze - consistent output [*]!
;
entry:
  %m.3 = mul nsw i64 -3, %m
  %const = sub i64 %m.3, 9223372036854775807
  %guard = icmp ne i64 %const, 0
  br i1 %guard, label %loop, label %exit

loop:
  %i = phi i64 [ 0, %entry ], [ %i.inc, %loop ]
  %offset.0 = phi i64 [ 0, %entry ], [ %offset.0.next, %loop ]
  %offset.1 = phi i64 [ %const, %entry ], [ %offset.1.next, %loop ]
  %gep.0 = getelementptr inbounds i8, ptr %A, i64 %offset.0
  %gep.1 = getelementptr inbounds i8, ptr %A, i64 %offset.1
  store i8 0, ptr %gep.0
  store i8 1, ptr %gep.1
  %i.inc = add nuw nsw i64 %i, 1
  %offset.0.next = add nsw i64 %offset.0, 3
  %offset.1.next = add nsw i64 %offset.1, -3
  %ec = icmp eq i64 %i.inc, 3074457345618258602
  br i1 %ec, label %exit, label %loop

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