[PATCH] D71600: PowerPC 32-bit - forces 8 byte lock/lock_free decisions at compiled time

[Alfredo Dal'Ava Júnior via Phabricator via llvm-commits]

adalava updated this revision to Diff 243520.
adalava added a comment.

fix typo found by @dim


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D71600/new/

https://reviews.llvm.org/D71600

Files:
  clang/lib/AST/ExprConstant.cpp
  compiler-rt/lib/builtins/atomic.c


Index: compiler-rt/lib/builtins/atomic.c
===================================================================
--- compiler-rt/lib/builtins/atomic.c
+++ compiler-rt/lib/builtins/atomic.c
@@ -119,13 +119,20 @@
   return locks + (hash & SPINLOCK_MASK);
 }
 
-/// Macros for determining whether a size is lock free.  Clang can not yet
-/// codegen __atomic_is_lock_free(16), so for now we assume 16-byte values are
-/// not lock free.
+/// Macros for determining whether a size is lock free.
 #define IS_LOCK_FREE_1 __c11_atomic_is_lock_free(1)
 #define IS_LOCK_FREE_2 __c11_atomic_is_lock_free(2)
 #define IS_LOCK_FREE_4 __c11_atomic_is_lock_free(4)
+
+/// 32 bit PowerPC doesn't support 8-byte lock_free atomics
+#if !defined(__powerpc64__) && defined(__powerpc__)
+#define IS_LOCK_FREE_8 0
+#else
 #define IS_LOCK_FREE_8 __c11_atomic_is_lock_free(8)
+#endif
+
+/// Clang can not yet codegen __atomic_is_lock_free(16), so for now we assume
+/// 16-byte values are not lock free.
 #define IS_LOCK_FREE_16 0
 
 /// Macro that calls the compiler-generated lock-free versions of functions
Index: clang/lib/AST/ExprConstant.cpp
===================================================================
--- clang/lib/AST/ExprConstant.cpp
+++ clang/lib/AST/ExprConstant.cpp
@@ -11206,6 +11206,15 @@
       }
     }
 
+    // Avoid emitting call for runtime decision on PowerPC 32-bit
+    // The lock free possibilities on this platform are covered by the lines 
+    // above and we know in advance other cases require lock.
+    // This may need to be restricted to specific operating systems in the future,
+    // as some (perhaps AIX) might provide libatomic and prefer to use it instead
+    if (Info.Ctx.getTargetInfo().getTriple().getArch() == llvm::Triple::ppc) {
+        return Success(0, E);
+    }
+
     return BuiltinOp == Builtin::BI__atomic_always_lock_free ?
         Success(0, E) : Error(E);
   }


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