[Atomic][X8664] set max atomic inline width according to the target

This is to fix PR31620. MaxAtomicInlineWidth is set to 128 for x86_64. However
for target without cx16 support, 128 atomic operation will generate __sync_*
libcalls. The patch set MaxAtomicInlineWidth to 64 if the target doesn't support
cx16.

Differential Revision: https://reviews.llvm.org/D38046

llvm-svn: 313992

2 files changed, 8 insertions, 1 deletions

diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
index 3c1c08bb057..a9a5f4ddcfb 100644
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -620,6 +620,7 @@ TargetInfo::CreateTargetInfo(DiagnosticsEngine &Diags,
 
   Target->setSupportedOpenCLOpts();
   Target->setOpenCLExtensionOpts();
+  Target->setMaxAtomicWidth();
 
   if (!Target->validateTarget(Diags))
     return nullptr;
diff --git a/clang/lib/Basic/Targets/X86.h b/clang/lib/Basic/Targets/X86.h
index 21ae4ff4e67..a08eeec59dc 100644
--- a/clang/lib/Basic/Targets/X86.h
+++ b/clang/lib/Basic/Targets/X86.h
@@ -814,7 +814,7 @@ public:
 
     // x86-64 has atomics up to 16 bytes.
     MaxAtomicPromoteWidth = 128;
-    MaxAtomicInlineWidth = 128;
+    MaxAtomicInlineWidth = 64;
   }
 
   BuiltinVaListKind getBuiltinVaListKind() const override {
@@ -872,6 +872,12 @@ public:
                                                          HasSizeMismatch);
   }
 
+  void setMaxAtomicWidth() override {
+    if (hasFeature("cx16"))
+      MaxAtomicInlineWidth = 128;
+    return;
+  }
+
   ArrayRef<Builtin::Info> getTargetBuiltins() const override;
 };