commit cee4a1c957426e9477c8579ff960c8c2bd4af9e2
author serge-sans-paille <sguelton@redhat.com> Wed Dec 11 21:30:10 2019 +0100
committer serge-sans-paille <sguelton@redhat.com> Thu Jan 09 17:31:00 2020 +0100
tree 6ae81e86924a355e2ce2fe41118af4f2b71a035a
parent d27a15fed79c8e8484825ce6c3ce1682daeb1547

Improve support of GNU mempcpy

- Lower to the memcpy intrinsic
- Raise warnings when size/bounds are known

Differential Revision: https://reviews.llvm.org/D71374

clang/lib/CodeGen/CGBuiltin.cpp

diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 4b89b1b..3fadf09 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -2500,7 +2500,9 @@
     return RValue::get(nullptr);
   }
   case Builtin::BImemcpy:
-  case Builtin::BI__builtin_memcpy: {
+  case Builtin::BI__builtin_memcpy:
+  case Builtin::BImempcpy:
+  case Builtin::BI__builtin_mempcpy: {
     Address Dest = EmitPointerWithAlignment(E->getArg(0));
     Address Src = EmitPointerWithAlignment(E->getArg(1));
     Value *SizeVal = EmitScalarExpr(E->getArg(2));
@@ -2509,7 +2511,11 @@
     EmitNonNullArgCheck(RValue::get(Src.getPointer()), E->getArg(1)->getType(),
                         E->getArg(1)->getExprLoc(), FD, 1);
     Builder.CreateMemCpy(Dest, Src, SizeVal, false);
-    return RValue::get(Dest.getPointer());
+    if (BuiltinID == Builtin::BImempcpy ||
+        BuiltinID == Builtin::BI__builtin_mempcpy)
+      return RValue::get(Builder.CreateInBoundsGEP(Dest.getPointer(), SizeVal));
+    else
+      return RValue::get(Dest.getPointer());
   }
 
   case Builtin::BI__builtin_char_memchr: