From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Fri, 7 Sep 2018 21:24:27 +0000 (+0000)
Subject: Make -Watomic-alignment say whether the atomic operation was oversized
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=52bc9ec1020a6e47415bab0e435465f26eaf15d9;p=clang

Make -Watomic-alignment say whether the atomic operation was oversized
or misaligned.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@341710 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 78d1b0f284..9945b22558 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -7093,8 +7093,8 @@ def warn_atomic_op_has_invalid_memory_order : Warning<
 def err_atomic_op_has_invalid_synch_scope : Error<
   "synchronization scope argument to atomic operation is invalid">;
 def warn_atomic_op_misaligned : Warning<
-  "misaligned or large atomic operation may incur significant performance penalty">,
-  InGroup<DiagGroup<"atomic-alignment">>;
+  "%select{large|misaligned}0 atomic operation may incur "
+  "significant performance penalty">, InGroup<DiagGroup<"atomic-alignment">>;
 
 def err_overflow_builtin_must_be_int : Error<
   "operand argument to overflow builtin must be an integer (%0 invalid)">;
diff --git a/lib/CodeGen/CGAtomic.cpp b/lib/CodeGen/CGAtomic.cpp
index eaf29dfff2..5b63b3ffca 100644
--- a/lib/CodeGen/CGAtomic.cpp
+++ b/lib/CodeGen/CGAtomic.cpp
@@ -765,11 +765,15 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
   std::tie(sizeChars, alignChars) = getContext().getTypeInfoInChars(AtomicTy);
   uint64_t Size = sizeChars.getQuantity();
   unsigned MaxInlineWidthInBits = getTarget().getMaxAtomicInlineWidth();
-  bool UseLibcall = ((Ptr.getAlignment() % sizeChars) != 0 ||
-                     getContext().toBits(sizeChars) > MaxInlineWidthInBits);
 
-  if (UseLibcall)
-    CGM.getDiags().Report(E->getBeginLoc(), diag::warn_atomic_op_misaligned);
+  bool Oversized = getContext().toBits(sizeChars) > MaxInlineWidthInBits;
+  bool Misaligned = (Ptr.getAlignment() % sizeChars) != 0;
+  bool UseLibcall = Misaligned | Oversized;
+
+  if (UseLibcall) {
+    CGM.getDiags().Report(E->getBeginLoc(), diag::warn_atomic_op_misaligned)
+        << !Oversized;
+  }
 
   llvm::Value *Order = EmitScalarExpr(E->getOrder());
   llvm::Value *Scope =
diff --git a/test/CodeGen/atomics-sema-alignment.c b/test/CodeGen/atomics-sema-alignment.c
index 364743dd53..9443af354e 100644
--- a/test/CodeGen/atomics-sema-alignment.c
+++ b/test/CodeGen/atomics-sema-alignment.c
@@ -12,10 +12,10 @@ typedef int __attribute__((aligned(1))) unaligned_int;
 
 void func(IntPair *p) {
   IntPair res;
-  __atomic_load(p, &res, 0); // expected-warning {{misaligned or large atomic operation may incur significant performance penalty}}
-  __atomic_store(p, &res, 0); // expected-warning {{misaligned or large atomic operation may incur significant performance penalty}}
-  __atomic_fetch_add((unaligned_int *)p, 1, 2); // expected-warning {{misaligned or large atomic operation may incur significant performance penalty}}
-  __atomic_fetch_sub((unaligned_int *)p, 1, 3); // expected-warning {{misaligned or large atomic operation may incur significant performance penalty}}
+  __atomic_load(p, &res, 0); // expected-warning {{misaligned atomic operation may incur significant performance penalty}}
+  __atomic_store(p, &res, 0); // expected-warning {{misaligned atomic operation may incur significant performance penalty}}
+  __atomic_fetch_add((unaligned_int *)p, 1, 2); // expected-warning {{misaligned atomic operation may incur significant performance penalty}}
+  __atomic_fetch_sub((unaligned_int *)p, 1, 3); // expected-warning {{misaligned atomic operation may incur significant performance penalty}}
 }
 
 void func1(LongStruct *p) {