[Clang] Fix bug the way we handle duplicate vs conflicting values with loop attribute 'code_align'

[smanna12]

#70762 added support for new loop attribute [[clang::code_align()]].

This patch fixes bugs for the test cases below that misses diagnostics due to discontinue to while loop during checking duplicate vs conflicting code_align attribute values in routine CheckForDuplicateLoopAttrs().

[[clang::code_align(4)]]
[[clang::code_align(4)]]
[[clang::code_align(8)]]
for(int I=0; I<128; ++I) { bar(I); }

[[clang::code_align(4)]]
[[clang::code_align(4)]]
[[clang::code_align(8)]]
[[clang::code_align(32)]]
for(int I=0; I<128; ++I) { bar(I); }

[llvmbot]

@llvm/pr-subscribers-clang

Author: None (smanna12)

Changes

#70762 added support for new loop attribute [[clang::code_align()]].

This patch fixes bug for the test case below that misses diagnostic due to discontinue to loop while checking duplicate vs conflicting code_align attribute values.

[[clang::code_align(4)]]
[[clang::code_align(4)]]
[[clang::code_align(8)]]
for(int I=0; I<128; ++I) { bar(I); }

---

Full diff: https://github.com/llvm/llvm-project/pull/87372.diff

2 Files Affected:

• (modified) clang/lib/Sema/SemaStmtAttr.cpp (+1-1)
• (modified) clang/test/Sema/code_align.c (+10)

diff --git a/clang/lib/Sema/SemaStmtAttr.cpp b/clang/lib/Sema/SemaStmtAttr.cpp
index 691857e88beb49..b6df4ccf9400c7 100644
--- a/clang/lib/Sema/SemaStmtAttr.cpp
+++ b/clang/lib/Sema/SemaStmtAttr.cpp
@@ -405,8 +405,8 @@ static void CheckForDuplicateLoopAttrs(Sema &S, ArrayRef<const Attr *> Attrs) {
       S.Diag((*LastFoundItr)->getLocation(), diag::err_loop_attr_conflict)
           << *FirstItr;
       S.Diag((*FirstItr)->getLocation(), diag::note_previous_attribute);
+      return;
     }
-    return;
   }
 }
 
diff --git a/clang/test/Sema/code_align.c b/clang/test/Sema/code_align.c
index d494d5ea1558f0..0656358dc367b9 100644
--- a/clang/test/Sema/code_align.c
+++ b/clang/test/Sema/code_align.c
@@ -62,6 +62,11 @@ void foo1(int A)
   [[clang::code_align(64)]] // expected-error{{conflicting loop attribute 'code_align'}}
   for(int I=0; I<128; ++I) { bar(I); }
 
+  [[clang::code_align(4)]] // expected-note{{previous attribute is here}}
+  [[clang::code_align(4)]] // OK
+  [[clang::code_align(8)]] // expected-error{{conflicting loop attribute 'code_align'}}
+  for(int I=0; I<128; ++I) { bar(I); }
+
   // expected-error@+1{{'code_align' attribute requires an integer argument which is a constant power of two between 1 and 4096 inclusive; provided argument was 7}}
   [[clang::code_align(7)]]
   for(int I=0; I<128; ++I) { bar(I); }
@@ -135,6 +140,11 @@ void code_align_dependent() {
   [[clang::code_align(E)]] // cpp-local-error{{conflicting loop attribute 'code_align'}}
   for(int I=0; I<128; ++I) { bar(I); }
 
+  [[clang::code_align(A)]] // cpp-local-note{{previous attribute is here}}
+  [[clang::code_align(A)]] // OK
+  [[clang::code_align(E)]] // cpp-local-error{{conflicting loop attribute 'code_align'}}
+  for(int I=0; I<128; ++I) { bar(I); }
+
   // cpp-local-error@+1{{'code_align' attribute requires an integer argument which is a constant power of two between 1 and 4096 inclusive; provided argument was 23}}
   [[clang::code_align(B)]]
   for(int I=0; I<128; ++I) { bar(I); }

[smanna12]

Thank you @erichkeane for reviews!