[PATCH] openacc: Fix atomic_capture-2.c iteration-ordering issues

[Julian Brown]

The test case was written with assumptions about loop iteration ordering
that are not guaranteed by OpenACC and do not apply on all targets,
in particular AMD GCN. This patch removes those assumptions.

Tested with offloading to AMD GCN. I will apply shortly.

Julian

2020-09-08  Julian Brown  <jul...@codesourcery.com>

libgomp/
        * testsuite/libgomp.oacc-c-c++-common/atomic_capture-2.c: Remove
        iteration-ordering assumptions.
---
 .../atomic_capture-2.c                        | 92 +++++++++----------
 1 file changed, 43 insertions(+), 49 deletions(-)

diff --git a/libgomp/testsuite/libgomp.oacc-c-c++-common/atomic_capture-2.c 
b/libgomp/testsuite/libgomp.oacc-c-c++-common/atomic_capture-2.c
index 842f2de4722..4f83f03899d 100644
--- a/libgomp/testsuite/libgomp.oacc-c-c++-common/atomic_capture-2.c
+++ b/libgomp/testsuite/libgomp.oacc-c-c++-common/atomic_capture-2.c
@@ -37,11 +37,9 @@ main(int argc, char **argv)
       imin = idata[i] < imin ? idata[i] : imin;
     }
 
-  if (imax != 1234 || imin != 0)
+  if (imax != 1234 || imin < 0 || imin > 1)
     abort ();
 
-  return 0;
-
   igot = 0;
   iexp = 32;
 
@@ -443,17 +441,16 @@ main(int argc, char **argv)
     }
   }
 
+  int ones = 0, zeros = 0;
+
   for (i = 0; i < N; i++)
-    if (i % 2 == 0)
-      {
-       if (idata[i] != 1)
-         abort ();
-      }
-    else
-      {
-       if (idata[i] != 0)
-         abort ();
-      }
+    if (idata[i] == 1)
+      ones++;
+    else if (idata[i] == 0)
+      zeros++;
+
+  if (ones != N / 2 || zeros != N / 2)
+    abort ();
 
   if (iexp != igot)
     abort ();
@@ -491,17 +488,16 @@ main(int argc, char **argv)
       }
   }
 
+  ones = zeros = 0;
+
   for (i = 0; i < N; i++)
-    if (i % 2 == 0)
-      {
-       if (idata[i] != 0)
-         abort ();
-      }
-    else
-      {
-       if (idata[i] != 1)
-         abort ();
-      }
+    if (idata[i] == 1)
+      ones++;
+    else if (idata[i] == 0)
+      zeros++;
+
+  if (ones != N / 2 || zeros != N / 2)
+    abort ();
 
   if (iexp != igot)
     abort ();
@@ -579,7 +575,7 @@ main(int argc, char **argv)
   if (lexp != lgot)
     abort ();
 
-  lgot = 2LL;
+  lgot = 2LL << N;
   lexp = 2LL;
 
 #pragma acc data copy (lgot, ldata[0:N])
@@ -587,7 +583,7 @@ main(int argc, char **argv)
 #pragma acc parallel loop
     for (i = 0; i < N; i++)
       {
-        long long expr = 1LL << N;
+       long long expr = 2LL;
 
 #pragma acc atomic capture
         { lgot = lgot / expr; ldata[i] = lgot; }
@@ -1450,17 +1446,16 @@ main(int argc, char **argv)
       }
   }
 
+  ones = zeros = 0;
+
   for (i = 0; i < N; i++)
-    if (i % 2 == 0)
-      {
-       if (fdata[i] != 1.0)
-         abort ();
-      }
-    else
-      {
-       if (fdata[i] != 0.0)
-         abort ();
-      }
+    if (fdata[i] == 1.0)
+      ones++;
+    else if (fdata[i] == 0.0)
+      zeros++;
+
+  if (ones != N / 2 || zeros != N / 2)
+    abort ();
 
   if (fexp != fgot)
     abort ();
@@ -1498,17 +1493,16 @@ main(int argc, char **argv)
       }
   }
 
+  ones = zeros = 0;
+
   for (i = 0; i < N; i++)
-    if (i % 2 == 0)
-      {
-       if (fdata[i] != 0.0)
-         abort ();
-      }
-    else
-      {
-       if (fdata[i] != 1.0)
-         abort ();
-      }
+    if (fdata[i] == 1.0)
+      ones++;
+    else if (fdata[i] == 0.0)
+      zeros++;
+
+  if (ones != N / 2 || zeros != N / 2)
+    abort ();
 
   if (fexp != fgot)
     abort ();
@@ -1569,7 +1563,7 @@ main(int argc, char **argv)
     abort ();
 
   fgot = 8192.0*8192.0*64.0;
-  fexp = 1.0;
+  fexp = fgot;
 
 #pragma acc data copy (fgot, fdata[0:N])
   {
@@ -1586,15 +1580,15 @@ main(int argc, char **argv)
   if (fexp != fgot)
     abort ();
 
-  fgot = 4.0;
-  fexp = 4.0;
+  fgot = 2.0 * (1LL << N);
+  fexp = 2.0;
 
 #pragma acc data copy (fgot, fdata[0:N])
   {
 #pragma acc parallel loop
     for (i = 0; i < N; i++)
       {
-        long long expr = 1LL << N;
+       long long expr = 2LL;
 
 #pragma acc atomic capture
         { fgot = fgot / expr; fdata[i] = fgot; }
-- 
2.28.0