[clang-tidy] altera-id-dependent-backward-branch: refactor test

[yeputons-gh]

Summary

This is a preparation for future fixes that need more tests.

• Put all "Inferred Assignments" testing at the end
• Group together ID-dependent variable/member testing
• Group together unused inferred assignments
• Use a literal instead of get_local_size which may have special meaning
• Create a new struct for each variable because analysis is done per field, not per field per instance.

Depends on D145303

[carlosgalvezp]

LGTM!

[carlosgalvezp]

It seems I'm having trouble to download the patch with arcanist, would you mind rebasing on top of the main branch? Thanks!

[yeputons-gh]

Absolutely, give we few minutes. Maybe it conflicts with the previous revision that has already landed?

[yeputons-gh]

Rebased on top of the recent 'main'.

[carlosgalvezp]

In D145304#4169810, @yeputons-gh wrote:

Absolutely, give we few minutes. Maybe it conflicts with the previous revision that has already landed?

I believe so. I'm quite new to arcanist so I might be missing some tricks to handled chained patches. Rebase worked and I pushed now thanks!

clang-tools-extra/test/clang-tidy/checkers/altera/id-dependent-backward-branch.cpp

 // RUN: %check_clang_tidy %s altera-id-dependent-backward-branch %t -- -header-filter=.* "--" -cl-std=CL1.2 -c
 
-typedef struct ExampleStruct {
-  int IDDepField;
-} ExampleStruct;
-
 void error() {
   // ==== Conditional Expressions ====
   int accumulator = 0;
   for (int i = 0; i < get_local_id(0); i++) {
     // CHECK-NOTES: :[[@LINE-1]]:19: warning: backward branch (for loop) is ID-dependent due to ID function call and may cause performance degradation [altera-id-dependent-backward-branch]
     accumulator++;
   }
 
void error() {
   int ThreadID = get_local_id(0);
 
   while (j < ThreadID) {
     // CHECK-NOTES: :[[@LINE-1]]:10: warning: backward branch (while loop) is ID-dependent due to variable reference to 'ThreadID' and may cause performance degradation [altera-id-dependent-backward-branch]
     // CHECK-NOTES: :[[@LINE-4]]:3: note: assignment of ID-dependent variable ThreadID
     accumulator++;
   }
 
-  ExampleStruct Example;
-  Example.IDDepField = get_local_id(0);
-
-  // ==== Inferred Assignments ====
-  int ThreadID2 = ThreadID * get_local_size(0);
-
-  int ThreadID3 = Example.IDDepField; // OK: not used in any loops
-
-  ExampleStruct UnusedStruct = {
-      ThreadID * 2 // OK: not used in any loops
-  };
-
-  for (int i = 0; i < ThreadID2; i++) {
-    // CHECK-NOTES: :[[@LINE-1]]:19: warning: backward branch (for loop) is ID-dependent due to variable reference to 'ThreadID2' and may cause performance degradation [altera-id-dependent-backward-branch]
-    // CHECK-NOTES: :[[@LINE-10]]:3: note: inferred assignment of ID-dependent value from ID-dependent variable ThreadID
-    accumulator++;
-  }
-
   do {
     accumulator++;
   } while (j < ThreadID);
   // CHECK-NOTES: :[[@LINE-1]]:12: warning: backward branch (do loop) is ID-dependent due to variable reference to 'ThreadID' and may cause performance degradation [altera-id-dependent-backward-branch]
-  // CHECK-NOTES: :[[@LINE-30]]:3: note: assignment of ID-dependent variable ThreadID
+  // CHECK-NOTES: :[[@LINE-12]]:3: note: assignment of ID-dependent variable ThreadID
+
+  struct { int IDDepField; } Example;
+  Example.IDDepField = get_local_id(0);
 
   for (int i = 0; i < Example.IDDepField; i++) {
     // CHECK-NOTES: :[[@LINE-1]]:19: warning: backward branch (for loop) is ID-dependent due to member reference to 'IDDepField' and may cause performance degradation [altera-id-dependent-backward-branch]
-    // CHECK-NOTES: :[[@LINE-25]]:3: note: assignment of ID-dependent field IDDepField
+    // CHECK-NOTES: :[[@LINE-4]]:3: note: assignment of ID-dependent field IDDepField
     accumulator++;
   }
 
   while (j < Example.IDDepField) {
     // CHECK-NOTES: :[[@LINE-1]]:10: warning: backward branch (while loop) is ID-dependent due to member reference to 'IDDepField' and may cause performance degradation [altera-id-dependent-backward-branch]
-    // CHECK-NOTES: :[[@LINE-31]]:3: note: assignment of ID-dependent field IDDepField
+    // CHECK-NOTES: :[[@LINE-10]]:3: note: assignment of ID-dependent field IDDepField
     accumulator++;
   }
 
   do {
     accumulator++;
   } while (j < Example.IDDepField);
   // CHECK-NOTES: :[[@LINE-1]]:12: warning: backward branch (do loop) is ID-dependent due to member reference to 'IDDepField' and may cause performance degradation [altera-id-dependent-backward-branch]
-  // CHECK-NOTES: :[[@LINE-39]]:3: note: assignment of ID-dependent field IDDepField
+  // CHECK-NOTES: :[[@LINE-18]]:3: note: assignment of ID-dependent field IDDepField
+
+  // ==== Inferred Assignments ====
+  int ThreadID2 = ThreadID * 2;
+
+  for (int i = 0; i < ThreadID2; i++) {
+    // CHECK-NOTES: :[[@LINE-1]]:19: warning: backward branch (for loop) is ID-dependent due to variable reference to 'ThreadID2' and may cause performance degradation [altera-id-dependent-backward-branch]
+    // CHECK-NOTES: :[[@LINE-4]]:3: note: inferred assignment of ID-dependent value from ID-dependent variable ThreadID
+    accumulator++;
+  }
+
+  // ==== Unused Inferred Assignments ====
+  int UnusedThreadID = Example.IDDepField; // OK: not used in any loops
+
+  struct { int IDDepField; } UnusedStruct;
+  UnusedStruct.IDDepField = ThreadID * 2; // OK: not used in any loops
 }
 
 void success() {
   int accumulator = 0;
 
   for (int i = 0; i < 1000; i++) {
     if (i < get_local_id(0)) {
       accumulator++;
     }
   }
 }