llvm/test/Analysis/LoopAccessAnalysis/different_strides.ll

; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 5
; RUN: opt -passes="print<access-info>" %s 2>&1 | FileCheck %s

@a = dso_local local_unnamed_addr global [65536 x float] zeroinitializer, align 16

; Generated from the following C code:
; #define LEN 256 * 256
; float a[LEN];
;
; void different_strides() {
;   for (int i = 0; i < LEN - 1024 - 255; i++) {
;   #pragma clang loop interleave(disable)
;   #pragma clang loop unroll(disable)
;     for (int j = 0; j < 256; j++)
;       a[i + j + 1024] += a[j * 4 + i];
;   }
; }
; The load and store have different strides(4 and 16 bytes respectively) but the store
; is always at safe positive distance away from the load, thus BackwardVectorizable
define void @different_strides_backward_vectorizable() {
; CHECK-LABEL: 'different_strides_backward_vectorizable'
; CHECK-NEXT:    inner.body:
; CHECK-NEXT:      Memory dependences are safe
; CHECK-NEXT:      Dependences:
; CHECK-NEXT:        Forward:
; CHECK-NEXT:            %5 = load float, ptr %arrayidx8, align 4 ->
; CHECK-NEXT:            store float %add9, ptr %arrayidx8, align 4
; CHECK-EMPTY:
; CHECK-NEXT:      Run-time memory checks:
; CHECK-NEXT:      Grouped accesses:
; CHECK-EMPTY:
; CHECK-NEXT:      Non vectorizable stores to invariant address were not found in loop.
; CHECK-NEXT:      SCEV assumptions:
; CHECK-EMPTY:
; CHECK-NEXT:      Expressions re-written:
; CHECK-NEXT:    outer.header:
; CHECK-NEXT:      Report: loop is not the innermost loop
; CHECK-NEXT:      Dependences:
; CHECK-NEXT:      Run-time memory checks:
; CHECK-NEXT:      Grouped accesses:
; CHECK-EMPTY:
; CHECK-NEXT:      Non vectorizable stores to invariant address were not found in loop.
; CHECK-NEXT:      SCEV assumptions:
; CHECK-EMPTY:
; CHECK-NEXT:      Expressions re-written:
;
entry:
  br label %outer.header

outer.header:
  %i = phi i64 [ 0, %entry ], [ %i.next, %outer.latch ]
  %0 = add nuw nsw i64 %i, 1024
  br label %inner.body

inner.body:
  %j = phi i64 [ 0, %outer.header ], [ %j.next, %inner.body ]
  %1 = shl nuw nsw i64 %j, 2
  %2 = add nuw nsw i64 %1, %i
  %arrayidx = getelementptr inbounds [65536 x float], ptr @a, i64 0, i64 %2
  %3 = load float, ptr %arrayidx, align 4
  %4 = add nuw nsw i64 %0, %j
  %arrayidx8 = getelementptr inbounds [65536 x float], ptr @a, i64 0, i64 %4
  %5 = load float, ptr %arrayidx8, align 4
  %add9 = fadd fast float %5, %3
  store float %add9, ptr %arrayidx8, align 4
  %j.next = add nuw nsw i64 %j, 1
  %exitcond.not = icmp eq i64 %j.next, 256
  br i1 %exitcond.not, label %outer.latch, label %inner.body

outer.latch:
  %i.next = add nuw nsw i64 %i, 1
  %outerexitcond.not = icmp eq i64 %i.next, 64257
  br i1 %outerexitcond.not, label %exit, label %outer.header

exit:
  ret void
}


; Generated from following C code:
; void different_stride_and_not_vectorizable(){
;    for(int i = 0; i < LEN2; i++){
;        for(int j = 0 ; j < LEN; j++){
;            a[i + j + LEN] += a[i + 4*j];
;        }
;    }
; }
; The load and store have different strides, but the store and load are not at a
; safe distance away from each other, thus not safe for vectorization.
define void @different_stride_and_not_vectorizable() {
; CHECK-LABEL: 'different_stride_and_not_vectorizable'
; CHECK-NEXT:    inner.body:
; CHECK-NEXT:      Report: unsafe dependent memory operations in loop. Use #pragma clang loop distribute(enable) to allow loop distribution to attempt to isolate the offending operations into a separate loop
; CHECK-NEXT:  Unknown data dependence.
; CHECK-NEXT:      Dependences:
; CHECK-NEXT:        Unknown:
; CHECK-NEXT:            %3 = load float, ptr %arrayidx, align 4 ->
; CHECK-NEXT:            store float %add9, ptr %arrayidx8, align 4
; CHECK-EMPTY:
; CHECK-NEXT:        Forward:
; CHECK-NEXT:            %5 = load float, ptr %arrayidx8, align 4 ->
; CHECK-NEXT:            store float %add9, ptr %arrayidx8, align 4
; CHECK-EMPTY:
; CHECK-NEXT:      Run-time memory checks:
; CHECK-NEXT:      Grouped accesses:
; CHECK-EMPTY:
; CHECK-NEXT:      Non vectorizable stores to invariant address were not found in loop.
; CHECK-NEXT:      SCEV assumptions:
; CHECK-EMPTY:
; CHECK-NEXT:      Expressions re-written:
; CHECK-NEXT:    outer.header:
; CHECK-NEXT:      Report: loop is not the innermost loop
; CHECK-NEXT:      Dependences:
; CHECK-NEXT:      Run-time memory checks:
; CHECK-NEXT:      Grouped accesses:
; CHECK-EMPTY:
; CHECK-NEXT:      Non vectorizable stores to invariant address were not found in loop.
; CHECK-NEXT:      SCEV assumptions:
; CHECK-EMPTY:
; CHECK-NEXT:      Expressions re-written:
;
entry:
  br label %outer.header

outer.header:
  %i = phi i64 [ 0, %entry ], [ %i.next, %outer.latch ]
  %0 = add nuw nsw i64 %i, 256
  br label %inner.body

inner.body:
  %j = phi i64 [ 0, %outer.header ], [ %j.next, %inner.body ]
  %1 = shl nuw nsw i64 %j, 2
  %2 = add nuw nsw i64 %1, %i
  %arrayidx = getelementptr inbounds [65536 x float], ptr @a, i64 0, i64 %2
  %3 = load float, ptr %arrayidx, align 4
  %4 = add nuw nsw i64 %0, %j
  %arrayidx8 = getelementptr inbounds [65536 x float], ptr @a, i64 0, i64 %4
  %5 = load float, ptr %arrayidx8, align 4
  %add9 = fadd fast float %5, %3
  store float %add9, ptr %arrayidx8, align 4
  %j.next = add nuw nsw i64 %j, 1
  %exitcond.not = icmp eq i64 %j.next, 256
  br i1 %exitcond.not, label %outer.latch, label %inner.body

outer.latch:
  %i.next = add nuw nsw i64 %i, 1
  %exitcond29.not = icmp eq i64 %i.next, 65536
  br i1 %exitcond29.not, label %exit, label %outer.header

exit:
  ret void
}