[PATCH] D37310: [Atomic] Merge alignment information from Decl and from Type when emit atomic expression.

[Wei Mi via Phabricator via cfe-commits]

wmi updated this revision to Diff 114300.
wmi added a comment.

Address John's comment.


Repository:
  rL LLVM

https://reviews.llvm.org/D37310

Files:
  lib/CodeGen/CGAtomic.cpp
  test/CodeGenCXX/atomic-align.cpp


Index: test/CodeGenCXX/atomic-align.cpp
===================================================================
--- test/CodeGenCXX/atomic-align.cpp
+++ test/CodeGenCXX/atomic-align.cpp
@@ -0,0 +1,30 @@
+// RUN: %clang_cc1 %s -std=c++11 -emit-llvm -o - -triple=x86_64-linux-gnu | FileCheck %s
+
+struct AM {
+  int f1, f2;
+};
+alignas(8) AM m;
+AM load1() {
+  AM am;
+  // m is declared to align to 8bytes, so generate load atomic instead
+  // of libcall.
+  // CHECK-LABEL: @_Z5load1v
+  // CHECK: load atomic {{.*}} monotonic
+  __atomic_load(&m, &am, 0);
+  return am;
+}
+
+struct BM {
+  int f1;
+  alignas(8) AM f2;
+};
+BM bm;
+AM load2() {
+  AM am;
+  // BM::f2 is declared to align to 8bytes, so generate load atomic instead
+  // of libcall.
+  // CHECK-LABEL: @_Z5load2v
+  // CHECK: load atomic {{.*}} monotonic
+  __atomic_load(&bm.f2, &am, 0);
+  return am;
+}
Index: lib/CodeGen/CGAtomic.cpp
===================================================================
--- lib/CodeGen/CGAtomic.cpp
+++ lib/CodeGen/CGAtomic.cpp
@@ -745,19 +745,19 @@
   QualType MemTy = AtomicTy;
   if (const AtomicType *AT = AtomicTy->getAs<AtomicType>())
     MemTy = AT->getValueType();
-  CharUnits sizeChars, alignChars;
-  std::tie(sizeChars, alignChars) = getContext().getTypeInfoInChars(AtomicTy);
-  uint64_t Size = sizeChars.getQuantity();
-  unsigned MaxInlineWidthInBits = getTarget().getMaxAtomicInlineWidth();
-  bool UseLibcall = (sizeChars != alignChars ||
-                     getContext().toBits(sizeChars) > MaxInlineWidthInBits);
-
   llvm::Value *IsWeak = nullptr, *OrderFail = nullptr;
 
   Address Val1 = Address::invalid();
   Address Val2 = Address::invalid();
   Address Dest = Address::invalid();
-  Address Ptr(EmitScalarExpr(E->getPtr()), alignChars);
+  Address Ptr = EmitPointerWithAlignment(E->getPtr());
+
+  CharUnits sizeChars, alignChars;
+  std::tie(sizeChars, alignChars) = getContext().getTypeInfoInChars(AtomicTy);
+  uint64_t Size = sizeChars.getQuantity();
+  unsigned MaxInlineWidthInBits = getTarget().getMaxAtomicInlineWidth();
+  bool UseLibcall = (sizeChars != Ptr.getAlignment() ||
+                     getContext().toBits(sizeChars) > MaxInlineWidthInBits);
 
   if (E->getOp() == AtomicExpr::AO__c11_atomic_init ||
       E->getOp() == AtomicExpr::AO__opencl_atomic_init) {


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D37310.114300.patch
Type: text/x-patch
Size: 2315 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20170908/bb574686/attachment-0001.bin>