Address review comments

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -10030,7 +10030,7 @@ def err_loop_attr_duplication : Error<
   "duplicate loop attribute %0">;
 def err_attribute_power_of_two_in_range : Error<
   "%0 attribute requires an integer argument which is a constant power of two "
-  "between %1 and %2 inclusive - got %3">;
+  "between %1 and %2 inclusive; got %3">;
 
 def warn_def_missing_case : Warning<"%plural{"
   "1:enumeration value %1 not explicitly handled in switch|"

clang/lib/CodeGen/CGLoopInfo.cpp

@@ -800,12 +800,10 @@ void LoopInfoStack::push(BasicBlock *Header, clang::ASTContext &Ctx,
   // Identify loop attribute 'code_align' from Attrs.
   // For attribute code_align:
   // n - 'llvm.loop.align i32 n' metadata will be emitted.
-  for (const auto *A : Attrs) {
-    if (const auto *CodeAlign = dyn_cast<CodeAlignAttr>(A)) {
-      const auto *CE = cast<ConstantExpr>(CodeAlign->getAlignment());
-      llvm::APSInt ArgVal = CE->getResultAsAPSInt();
-      setCodeAlign(ArgVal.getSExtValue());
-    }
+  if (const auto *CodeAlign = getSpecificAttr<const CodeAlignAttr>(Attrs)) {
+    const auto *CE = cast<ConstantExpr>(CodeAlign->getAlignment());
+    llvm::APSInt ArgVal = CE->getResultAsAPSInt();
+    setCodeAlign(ArgVal.getSExtValue());
   }
 
   setMustProgress(MustProgress);

clang/lib/Sema/SemaStmtAttr.cpp

@@ -331,17 +331,11 @@ CodeAlignAttr *Sema::BuildCodeAlignAttr(const AttributeCommonInfo &CI,
       return nullptr;
     E = Res.get();
 
-    // This attribute requires a strictly positive value.
-    if (ArgVal <= 0) {
-      Diag(E->getExprLoc(), diag::err_attribute_requires_positive_integer)
-          << CI << /*positive*/ 0;
-      return nullptr;
-    }
-
     // This attribute requires an integer argument which is a constant power of
     // two between 1 and 4096 inclusive.
     int AlignValue = ArgVal.getSExtValue();
-    if (AlignValue > CodeAlignAttr::getMaxValue() || !ArgVal.isPowerOf2()) {
+    if (AlignValue < CodeAlignAttr::getMinValue() ||
+        AlignValue > CodeAlignAttr::getMaxValue() || !ArgVal.isPowerOf2()) {
       Diag(CI.getLoc(), diag::err_attribute_power_of_two_in_range)
           << CI << CodeAlignAttr::getMinValue() << CodeAlignAttr::getMaxValue()
           << AlignValue;

clang/test/Sema/code_align.c

@@ -24,11 +24,11 @@ void bar(int);
 // cpp-local-note@+1 {{declared here}}
 void foo1(int A)
 {
-  // expected-error@+1 {{'code_align' attribute requires a positive integral compile time constant expression}}
+  // expected-error@+1 {{'code_align' attribute requires an integer argument which is a constant power of two between 1 and 4096 inclusive; got 0}}
   [[clang::code_align(0)]]
   for(int I=0; I<128; ++I) { bar(I); }
 
-  // expected-error@+1 {{'code_align' attribute requires a positive integral compile time constant expression}}
+  // expected-error@+1 {{'code_align' attribute requires an integer argument which is a constant power of two between 1 and 4096 inclusive; got -4}}
   [[clang::code_align(-4)]]
   for(int I=0; I<128; ++I) { bar(I); }
 
@@ -58,11 +58,11 @@ void foo1(int A)
   [[clang::code_align(64)]] // expected-error {{duplicate 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 - got 7}}
+  // expected-error@+1 {{'code_align' attribute requires an integer argument which is a constant power of two between 1 and 4096 inclusive; got 7}}
   [[clang::code_align(7)]]
   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 - got 5000}}
+  // expected-error@+1 {{'code_align' attribute requires an integer argument which is a constant power of two between 1 and 4096 inclusive; got 5000}}
   [[clang::code_align(5000)]]
   for(int I=0; I<128; ++I) { bar(I); }
 
@@ -103,7 +103,7 @@ void code_align_dependent() {
   [[clang::code_align(B)]] // cpp-local-error  {{duplicate loop attribute 'code_align'}}
   for(int I=0; I<128; ++I) { bar(I); }
 
-  // cpp-local-error@+2{{'code_align' attribute requires a positive integral compile time constant expression}}
+  // cpp-local-error@+2{{'code_align' attribute requires an integer argument which is a constant power of two between 1 and 4096 inclusive; got -10}}
   // cpp-local-note@#neg-instantiation {{in instantiation of function template specialization}}
   [[clang::code_align(D)]]
   for(int I=0; I<128; ++I) { bar(I); }