Emit the exact size for the invariant intrinsics.

llvm-svn: 151010

2 files changed, 12 insertions, 9 deletions

diff --git a/clang/lib/CodeGen/CGDeclCXX.cpp b/clang/lib/CodeGen/CGDeclCXX.cpp
index d8ece58d6e5..fac38a32427 100644
--- a/clang/lib/CodeGen/CGDeclCXX.cpp
+++ b/clang/lib/CodeGen/CGDeclCXX.cpp
@@ -103,7 +103,8 @@ static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D,
 
 /// Emit code to cause the variable at the given address to be considered as
 /// constant from this point onwards.
-static void EmitDeclInvariant(CodeGenFunction &CGF, llvm::Constant *Addr) {
+static void EmitDeclInvariant(CodeGenFunction &CGF, const VarDecl &D,
+                              llvm::Constant *Addr) {
   // Don't emit the intrinsic if we're not optimizing.
   if (!CGF.CGM.getCodeGenOpts().OptimizationLevel)
     return;
@@ -112,8 +113,10 @@ static void EmitDeclInvariant(CodeGenFunction &CGF, llvm::Constant *Addr) {
   llvm::Intrinsic::ID InvStartID = llvm::Intrinsic::invariant_start;
   llvm::Constant *InvariantStart = CGF.CGM.getIntrinsic(InvStartID);
 
-  // Emit a call, with size -1 signifying the whole object.
-  llvm::Value *Args[2] = { llvm::ConstantInt::getSigned(CGF.Int64Ty, -1),
+  // Emit a call with the size in bytes of the object.
+  CharUnits WidthChars = CGF.getContext().getTypeSizeInChars(D.getType());
+  uint64_t Width = WidthChars.getQuantity();
+  llvm::Value *Args[2] = { llvm::ConstantInt::getSigned(CGF.Int64Ty, Width),
                            llvm::ConstantExpr::getBitCast(Addr, CGF.Int8PtrTy)};
   CGF.Builder.CreateCall(InvariantStart, Args);
 }
@@ -129,7 +132,7 @@ void CodeGenFunction::EmitCXXGlobalVarDeclInit(const VarDecl &D,
     if (PerformInit)
       EmitDeclInit(*this, D, DeclPtr);
     if (CGM.isTypeConstant(D.getType(), true))
-      EmitDeclInvariant(*this, DeclPtr);
+      EmitDeclInvariant(*this, D, DeclPtr);
     else
       EmitDeclDestroy(*this, D, DeclPtr);
     return;
diff --git a/clang/test/CodeGenCXX/init-invariant.cpp b/clang/test/CodeGenCXX/init-invariant.cpp
index 5d0ff8b0db0..9eb19896b6b 100644
--- a/clang/test/CodeGenCXX/init-invariant.cpp
+++ b/clang/test/CodeGenCXX/init-invariant.cpp
@@ -42,19 +42,19 @@ void e() {
 }
 
 // CHECK: call void @_ZN1AC1Ev({{.*}}* @a)
-// CHECK: call {{.*}}@llvm.invariant.start(i64 -1, i8* bitcast ({{.*}} @a to i8*))
+// CHECK: call {{.*}}@llvm.invariant.start(i64 4, i8* bitcast ({{.*}} @a to i8*))
 
 // CHECK: call void @_ZN1BC1Ev({{.*}}* @b)
-// CHECK-NOT: call {{.*}}@llvm.invariant.start(i64 -1, i8* bitcast ({{.*}} @b to i8*))
+// CHECK-NOT: call {{.*}}@llvm.invariant.start(i64 4, i8* bitcast ({{.*}} @b to i8*))
 
 // CHECK: call void @_ZN1CC1Ev({{.*}}* @c)
-// CHECK-NOT: call {{.*}}@llvm.invariant.start(i64 -1, i8* bitcast ({{.*}} @c to i8*))
+// CHECK-NOT: call {{.*}}@llvm.invariant.start(i64 4, i8* bitcast ({{.*}} @c to i8*))
 
 // CHECK: call i32 @_Z1fv(
 // CHECK: store {{.*}}, i32* @d
-// CHECK: call {{.*}}@llvm.invariant.start(i64 -1, i8* bitcast ({{.*}} @d to i8*))
+// CHECK: call {{.*}}@llvm.invariant.start(i64 4, i8* bitcast ({{.*}} @d to i8*))
 
 // CHECK: define void @_Z1ev(
 // CHECK: call void @_ZN1AC1Ev(%struct.A* @_ZZ1evE1a)
-// CHECK: call {{.*}}@llvm.invariant.start(i64 -1, i8* bitcast ({{.*}} @_ZZ1evE1a to i8*))
+// CHECK: call {{.*}}@llvm.invariant.start(i64 4, i8* bitcast ({{.*}} @_ZZ1evE1a to i8*))
 // CHECK-NOT: llvm.invariant.end