CodeGen: specify alignment + inbounds for automatic variable initialization

Summary: Automatic variable initialization was generating default-aligned stores (which are deprecated) instead of using the known alignment from the alloca. Further, they didn't specify inbounds.

Subscribers: dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D49209

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@337041 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 15 insertions, 0 deletions

diff --git a/lib/CodeGen/CGBuilder.h b/lib/CodeGen/CGBuilder.h
index 5b9c7a3c46..d2e5eb256d 100644
--- a/lib/CodeGen/CGBuilder.h
+++ b/lib/CodeGen/CGBuilder.h
@@ -244,6 +244,21 @@ public:
                    Addr.getAlignment().alignmentAtOffset(Offset));
   }
 
+  using CGBuilderBaseTy::CreateConstInBoundsGEP2_32;
+  Address CreateConstInBoundsGEP2_32(Address Addr, unsigned Idx0,
+                                      unsigned Idx1, const llvm::DataLayout &DL,
+                                      const llvm::Twine &Name = "") {
+    auto *GEP = cast<llvm::GetElementPtrInst>(CreateConstInBoundsGEP2_32(
+        Addr.getElementType(), Addr.getPointer(), Idx0, Idx1, Name));
+    llvm::APInt Offset(
+        DL.getIndexSizeInBits(Addr.getType()->getPointerAddressSpace()), 0,
+        /*IsSigned=*/true);
+    if (!GEP->accumulateConstantOffset(DL, Offset))
+      llvm_unreachable("offset of GEP with constants is always computable");
+    return Address(GEP, Addr.getAlignment().alignmentAtOffset(
+                            CharUnits::fromQuantity(Offset.getSExtValue())));
+  }
+
   llvm::Value *CreateConstInBoundsByteGEP(llvm::Value *Ptr, CharUnits Offset,
                                           const llvm::Twine &Name = "") {
     assert(Ptr->getType()->getPointerElementType() == TypeCache.Int8Ty);