[Clang] Fix bugs the way we handle duplicate vs conflicting values with loop attribute 'code_align' (#87372)

#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); }

Author: smanna12

clang/lib/Sema/SemaStmtAttr.cpp

@@ -406,8 +406,8 @@ static void CheckForDuplicateLoopAttrs(Sema &S, ArrayRef<const Attr *> Attrs) {
           << *FirstItr;
       S.Diag((*FirstItr)->getLocation(), diag::note_previous_attribute);
     }
-    return;
   }
+  return;
 }
 
 static Attr *handleMSConstexprAttr(Sema &S, Stmt *St, const ParsedAttr &A,

clang/test/Sema/code_align.c

@@ -62,6 +62,17 @@ 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); }
+
+  [[clang::code_align(4)]]  // expected-note 2{{previous attribute is here}}
+  [[clang::code_align(4)]]  // OK
+  [[clang::code_align(8)]]  // expected-error{{conflicting loop attribute 'code_align'}}
+  [[clang::code_align(64)]] // 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 +146,17 @@ 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); }
+
+  [[clang::code_align(A)]] // cpp-local-note 2{{previous attribute is here}}
+  [[clang::code_align(A)]] // OK
+  [[clang::code_align(C)]] // cpp-local-error{{conflicting loop attribute 'code_align'}}
+  [[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); }