llvm-project/polly/test/Isl/CodeGen/single_loop_zero_iterations.ll

; RUN: opt %loadPolly -polly-detect-unprofitable -polly-ast -analyze  -S < %s | FileCheck %s

;#define N 20
;
;int main () {
;  int i;
;  int A[N];
;
;  A[0] = 0;
;
;  __sync_synchronize();
;
;  for (i = 0; i < 0; i++)
;    A[i] = 1;
;
;  __sync_synchronize();
;
;  if (A[0] == 0)
;    return 0;
;  else
;    return 1;
;}

target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"

define i32 @main() nounwind {
entry:
  %A = alloca [20 x i32], align 4                 ; <[20 x i32]*> [#uses=3]
  %arraydecay = getelementptr inbounds [20 x i32], [20 x i32]* %A, i32 0, i32 0 ; <i32*> [#uses=1]
  %arrayidx = getelementptr inbounds i32, i32* %arraydecay, i64 0 ; <i32*> [#uses=1]
  store i32 0, i32* %arrayidx
  fence seq_cst
  br label %for.cond

for.cond:                                         ; preds = %for.inc, %entry
  %indvar = phi i64 [ %indvar.next, %for.inc ], [ 0, %entry ] ; <i64> [#uses=2]
  %arrayidx3 = getelementptr [20 x i32], [20 x i32]* %A, i64 0, i64 %indvar ; <i32*> [#uses=1]
  br i1 false, label %for.body, label %for.end

for.body:                                         ; preds = %for.cond
  store i32 1, i32* %arrayidx3
  br label %for.inc

for.inc:                                          ; preds = %for.body
  %indvar.next = add i64 %indvar, 1               ; <i64> [#uses=1]
  br label %for.cond

for.end:                                          ; preds = %for.cond
  fence seq_cst
  %arraydecay5 = getelementptr inbounds [20 x i32], [20 x i32]* %A, i32 0, i32 0 ; <i32*> [#uses=1]
  %arrayidx6 = getelementptr inbounds i32, i32* %arraydecay5, i64 0 ; <i32*> [#uses=1]
  %tmp7 = load i32, i32* %arrayidx6                    ; <i32> [#uses=1]
  %cmp8 = icmp eq i32 %tmp7, 0                    ; <i1> [#uses=1]
  br i1 %cmp8, label %if.then, label %if.else

if.then:                                          ; preds = %for.end
  br label %return

if.else:                                          ; preds = %for.end
  br label %return

return:                                           ; preds = %if.else, %if.then
  %retval.0 = phi i32 [ 0, %if.then ], [ 1, %if.else ] ; <i32> [#uses=1]
  ret i32 %retval.0
}

; CHECK: for region: 'for.cond => for.end.region' in function 'main':
; CHECK-NOT:   Stmt_for_body(0);