llvm/test/Transforms/LoopLoadElim/uncomputable-backedge-taken-count.ll

; RUN: opt -passes=loop-load-elim -S < %s | FileCheck %s
; RUN: opt -aa-pipeline=basic-aa -passes=loop-load-elim -S < %s | FileCheck %s

target datalayout = "e-m:o-i32:64-f80:128-n8:16:32:64-S128"

; TODO
; Make sure loop-load-elimination triggers for a loop with uncomputable
; backedge-taken counts when no runtime checks are required.
define void @load_elim_no_runtime_checks(ptr noalias %A, ptr noalias %B, ptr noalias %C, i32 %N) {
; CHECK-LABEL: load_elim_no_runtime_checks
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br label %for.body
;
entry:
  br label %for.body

for.body:                                         ; preds = %for.body, %entry
  %indvars.iv = phi i32 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
  %indvars.iv.next = add nuw nsw i32 %indvars.iv, 1

  %Aidx_next = getelementptr inbounds i32, ptr %A, i32 %indvars.iv.next
  %Bidx = getelementptr inbounds i32, ptr %B, i32 %indvars.iv
  %Cidx = getelementptr inbounds i32, ptr %C, i32 %indvars.iv
  %Aidx = getelementptr inbounds i32, ptr %A, i32 %indvars.iv

  %b = load i32, ptr %Bidx, align 4
  %a_p1 = add i32 %b, 2
  store i32 %a_p1, ptr %Aidx_next, align 4

  %a = load i32, ptr %Aidx, align 1
  %c = mul i32 %a, 2
  store i32 %c, ptr %Cidx, align 4

  %exitcond = icmp eq i32 %indvars.iv.next, %a
  br i1 %exitcond, label %for.end, label %for.body

for.end:                                          ; preds = %for.body
  ret void
}

; Make sure loop-load-elimination triggers for a loop with uncomputable
; backedge-taken counts when no runtime checks are required.
define void @load_elim_wrapping_runtime_checks(ptr noalias %A, ptr noalias %B, ptr noalias %C, i32 %N) {
; CHECK-LABEL: @load_elim_wrapping_runtime_checks
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br label %for.body
;
entry:
  br label %for.body

for.body:                                         ; preds = %for.body, %entry
  %indvars.iv = phi i32 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
  %indvars.iv.next = add i32 %indvars.iv, 1

  %Aidx_next = getelementptr inbounds i32, ptr %A, i32 %indvars.iv.next
  %Bidx = getelementptr inbounds i32, ptr %B, i32 %indvars.iv
  %Cidx = getelementptr inbounds i32, ptr %C, i32 %indvars.iv
  %Aidx = getelementptr inbounds i32, ptr %A, i32 %indvars.iv

  %b = load i32, ptr %Bidx, align 4
  %a_p1 = add i32 %b, 2
  store i32 %a_p1, ptr %Aidx_next, align 4

  %a = load i32, ptr %Aidx, align 1
  %c = mul i32 %a, 2
  store i32 %c, ptr %Cidx, align 4

  %exitcond = icmp eq i32 %indvars.iv.next, %a
  br i1 %exitcond, label %for.end, label %for.body

for.end:                                          ; preds = %for.body
  ret void
}

; Make sure we do not crash when dealing with uncomputable backedge-taken counts
; and a variable distance between accesses.
define void @uncomputable_btc_crash(ptr %row, i32 %filter, ptr noalias %exits) local_unnamed_addr #0 {
; CHECK-LABEL: @uncomputable_btc_crash
; CHECK-NEXT:  entry:
; CHECK-NEXT:    getelementptr
; CHECK-NEXT:    br label %loop
;
entry:
  %add.ptr = getelementptr inbounds i8, ptr %row, i32 %filter
  br label %loop

loop:
  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop ]
  %add.ptr.gep = getelementptr i8, ptr %add.ptr, i32 %iv
  %row.gep = getelementptr i8, ptr %row, i32 %iv
  %l = load i8, ptr %row.gep, align 1
  store i8 %l, ptr %add.ptr.gep, align 1
  %iv.next = add i32 %iv, 8
  %exit.gep = getelementptr i32, ptr %exits, i32 %iv
  %lv = load i32, ptr %exit.gep
  %c = icmp eq i32 %lv, 120
  br i1 %c, label %exit, label %loop

exit:
  ret void
}