clang/test/CodeGen/pragma-do-while.cpp

   1 // RUN: %clang_cc1 -emit-llvm %s -o - | FileCheck %s
   2
   3 // We expect to get a loop structure like this:
   4 //    do.body:                                       ; preds = %do.cond, ...
   5 //      ...
   6 //      br label %do.cond
   7 //    do.cond:                                       ; preds = %do.body
   8 //      ...
   9 //      br i1 %cmp, label %do.body, label %do.end
  10 //    do.end:                                        ; preds = %do.cond
  11 //      ...
  12 //
  13 // Verify that the loop metadata only is put on the backedge.
  14 //
  15 // CHECK-NOT: llvm.loop
  16 // CHECK-LABEL: do.cond:
  17 // CHECK: br {{.*}}, label %do.body, label %do.end, !llvm.loop ![[LMD1:[0-9]+]]
  18 // CHECK-LABEL: do.end:
  19 // CHECK-NOT: llvm.loop
  20 // CHECK: ![[LMD1]] = distinct !{![[LMD1]], [[LMD2:![0-9]+]], ![[LMD3:[0-9]+]]}
  21 // CHECK: [[LMD2]] = !{!"llvm.loop.mustprogress"}
  22 // CHECK: ![[LMD3]] = !{!"llvm.loop.unroll.count", i32 4}
  23
  24 int test(int a[], int n) {
  25   int i = 0;
  26   int sum = 0;
  27
  28 #pragma unroll 4
  29   do
  30   {
  31     a[i] = a[i] + 1;
  32     sum = sum + a[i];
  33     i++;
  34   } while (i < n);
  35
  36   return sum;
  37 }