test/Transforms/LoopVectorize/early-exit-umin-trip-count.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
; RUN: opt -S -passes=loop-vectorize %s | FileCheck %s

; TODO: The loop should be vectorized. The vectorizer needs to prove
;   (A umin B) u<= A to establish memory safety from the dereferenceable
;   assumption.
;
; long n = umin(count, length);
; for (long i = 0; i < n; i++)
;   if (ptr[i] == 0) return null;
; ...
define ptr @main(i32 %length, ptr %ptr, i64 %0) #0 {
; CHECK-LABEL: define ptr @main(
; CHECK-SAME: i32 [[LENGTH:%.*]], ptr [[PTR:%.*]], i64 [[TMP0:%.*]]) #[[ATTR0:[0-9]+]] {
; CHECK-NEXT:  [[ENTRY:.*:]]
; CHECK-NEXT:    [[NULL_CHECK0:%.*]] = icmp eq i64 [[TMP0]], 0
; CHECK-NEXT:    br i1 [[NULL_CHECK0]], label %[[DEOPT:.*]], label %[[PREHEADER:.*]]
; CHECK:       [[PREHEADER]]:
; CHECK-NEXT:    [[LENGTH_64:%.*]] = zext i32 [[LENGTH]] to i64
; CHECK-NEXT:    [[EXIT:%.*]] = call i64 @llvm.umin.i64(i64 [[TMP0]], i64 [[LENGTH_64]])
; CHECK-NEXT:    call void @llvm.assume(i1 true) [ "align"(ptr [[PTR]], i64 8), "dereferenceable"(ptr [[PTR]], i64 [[LENGTH_64]]) ]
; CHECK-NEXT:    [[NULL_CHECK:%.*]] = icmp eq i32 [[LENGTH]], 0
; CHECK-NEXT:    br i1 [[NULL_CHECK]], label %[[DEOPT]], label %[[SCALAR_PH:.*]]
; CHECK:       [[SCALAR_PH]]:
; CHECK-NEXT:    br label %[[LOOP:.*]]
; CHECK:       [[LOOP]]:
; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], %[[LATCH:.*]] ], [ 0, %[[SCALAR_PH]] ]
; CHECK-NEXT:    [[ELEMENT_GEP:%.*]] = getelementptr i8, ptr [[PTR]], i64 [[IV]]
; CHECK-NEXT:    [[ELEMENT:%.*]] = load i8, ptr [[ELEMENT_GEP]], align 1
; CHECK-NEXT:    [[FOUND_CHECK:%.*]] = icmp eq i8 [[ELEMENT]], 0
; CHECK-NEXT:    br i1 [[FOUND_CHECK]], label %[[FOUND:.*]], label %[[LATCH]]
; CHECK:       [[LATCH]]:
; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
; CHECK-NEXT:    [[RANGE_CHECK:%.*]] = icmp ult i64 [[IV_NEXT]], [[EXIT]]
; CHECK-NEXT:    br i1 [[RANGE_CHECK]], label %[[LOOP]], label %[[DEOPT_LOOPEXIT:.*]]
; CHECK:       [[FOUND]]:
; CHECK-NEXT:    ret ptr null
; CHECK:       [[DEOPT_LOOPEXIT]]:
; CHECK-NEXT:    br label %[[DEOPT]]
; CHECK:       [[DEOPT]]:
; CHECK-NEXT:    unreachable
;
entry:
  %null_check0 = icmp eq i64 %0, 0
  br i1 %null_check0, label %deopt, label %preheader

preheader:                                        ; preds = %entry
  %length.64 = zext i32 %length to i64
  %exit = call i64 @llvm.umin.i64(i64 %0, i64 %length.64)
  call void @llvm.assume(i1 true) [ "align"(ptr %ptr, i64 8), "dereferenceable"(ptr %ptr, i64 %length.64) ]
  %null_check = icmp eq i32 %length, 0
  br i1 %null_check, label %deopt, label %loop

loop:                                             ; preds = %latch, %preheader
  %iv = phi i64 [ %iv.next, %latch ], [ 0, %preheader ]
  %element_gep = getelementptr i8, ptr %ptr, i64 %iv
  %element = load i8, ptr %element_gep, align 1
  %found_check = icmp eq i8 %element, 0
  br i1 %found_check, label %found, label %latch

latch:                                            ; preds = %loop
  %iv.next = add i64 %iv, 1
  %range_check = icmp ult i64 %iv.next, %exit
  br i1 %range_check, label %loop, label %deopt

found:                                            ; preds = %loop
  ret ptr null

deopt:                                            ; preds = %latch, %preheader
  unreachable
}

declare i64 @llvm.umin.i64(i64, i64)

declare void @llvm.assume(i1 noundef)

attributes #0 = { nofree nosync }