Fix a case where instcombine was stripping metadata (and alignment)

from stores when folding in bitcasts.

llvm-svn: 117265

2 files changed, 24 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
index b68fbc2db5c..992a5d9f6b4 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
@@ -330,7 +330,9 @@ static Instruction *InstCombineStoreToCast(InstCombiner &IC, StoreInst &SI) {
   
   NewCast = IC.Builder->CreateCast(opcode, SIOp0, CastDstTy,
                                    SIOp0->getName()+".c");
-  return new StoreInst(NewCast, CastOp);
+  SI.setOperand(0, NewCast);
+  SI.setOperand(1, CastOp);
+  return &SI;
 }
 
 /// equivalentAddressValues - Test if A and B will obviously have the same
diff --git a/llvm/test/Transforms/InstCombine/bitcast-store.ll b/llvm/test/Transforms/InstCombine/bitcast-store.ll
new file mode 100644
index 00000000000..e4a61e98e4f
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/bitcast-store.ll
@@ -0,0 +1,21 @@
+; RUN: opt -S -instcombine < %s | FileCheck %s
+
+; Instcombine should preserve metadata and alignment while
+; folding a bitcast into a store.
+
+; CHECK: store i32 (...)** bitcast (i8** getelementptr inbounds ([5 x i8*]* @G, i64 0, i64 2) to i32 (...)**), i32 (...)*** %0, align 16, !tag !0
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
+
+%struct.A = type { i32 (...)** }
+
+@G = external constant [5 x i8*]
+
+define void @foo(%struct.A* %a) nounwind {
+entry:
+  %0 = bitcast %struct.A* %a to i8***
+  store i8** getelementptr inbounds ([5 x i8*]* @G, i64 0, i64 2), i8*** %0, align 16, !tag !0
+  ret void
+}
+
+!0 = metadata !{metadata !"hello"}