From 5e01f80bf85b9a68352d4c146caa9ddcf6af6dcf Mon Sep 17 00:00:00 2001
From: Nick Lewycky <nicholas@mxc.ca>
Date: Thu, 11 Oct 2012 02:05:23 +0000
Subject: [PATCH] Don't crash when !tbaa.struct contents is invalid.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165693 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../InstCombine/InstCombineCalls.cpp          |  3 ++
 .../InstCombine/struct-assign-tbaa.ll         | 30 +++++++++++++++----
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp
index f92c4baeba7..04b7b2146f6 100644
--- a/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -111,10 +111,13 @@ Instruction *InstCombiner::SimplifyMemTransfer(MemIntrinsic *MI) {
         // get the TBAA tag describing our copy.
         if (MDNode *M = MI->getMetadata(LLVMContext::MD_tbaa_struct)) {
           if (M->getNumOperands() == 3 &&
+              M->getOperand(0) &&
               isa<ConstantInt>(M->getOperand(0)) &&
               cast<ConstantInt>(M->getOperand(0))->isNullValue() &&
+              M->getOperand(1) &&
               isa<ConstantInt>(M->getOperand(1)) &&
               cast<ConstantInt>(M->getOperand(1))->getValue() == Size &&
+              M->getOperand(2) &&
               isa<MDNode>(M->getOperand(2)))
             CopyMD = cast<MDNode>(M->getOperand(2));
         }
diff --git a/test/Transforms/InstCombine/struct-assign-tbaa.ll b/test/Transforms/InstCombine/struct-assign-tbaa.ll
index 4fbdb0ab67c..33a771e6d8b 100644
--- a/test/Transforms/InstCombine/struct-assign-tbaa.ll
+++ b/test/Transforms/InstCombine/struct-assign-tbaa.ll
@@ -2,25 +2,43 @@
 
 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-S128"
 
-%struct.foo = type { float }
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1) nounwind
 
 ; Verify that instcombine preserves TBAA tags when converting a memcpy into
 ; a scalar load and store.
 
+%struct.test1 = type { float }
+
+; CHECK: @test
 ; CHECK: %2 = load float* %0, align 4, !tbaa !0
 ; CHECK: store float %2, float* %1, align 4, !tbaa !0
-; CHECK: !0 = metadata !{metadata !"float", metadata !1}
-define void @test(%struct.foo* nocapture %a, %struct.foo* nocapture %b) {
+; CHECK: ret
+define void @test1(%struct.test1* nocapture %a, %struct.test1* nocapture %b) {
 entry:
-  %0 = bitcast %struct.foo* %a to i8*
-  %1 = bitcast %struct.foo* %b to i8*
+  %0 = bitcast %struct.test1* %a to i8*
+  %1 = bitcast %struct.test1* %b to i8*
   tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %0, i8* %1, i64 4, i32 4, i1 false), !tbaa.struct !3
   ret void
 }
 
-declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1) nounwind
+%struct.test2 = type { i32 (i8*, i32*, double*)** }
+
+define i32 (i8*, i32*, double*)*** @test2() {
+; CHECK: @test2
+; CHECK-NOT: memcpy
+; CHECK: ret
+  %tmp = alloca %struct.test2, align 8
+  %tmp1 = bitcast %struct.test2* %tmp to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %tmp1, i8* undef, i64 8, i32 8, i1 false), !tbaa.struct !4
+  %tmp2 = getelementptr %struct.test2* %tmp, i32 0, i32 0
+  %tmp3 = load i32 (i8*, i32*, double*)*** %tmp2
+  ret i32 (i8*, i32*, double*)*** %tmp2
+}
+
+; CHECK: !0 = metadata !{metadata !"float", metadata !1}
 
 !0 = metadata !{metadata !"Simple C/C++ TBAA"}
 !1 = metadata !{metadata !"omnipotent char", metadata !0}
 !2 = metadata !{metadata !"float", metadata !0}
 !3 = metadata !{i64 0, i64 4, metadata !2}
+!4 = metadata !{i64 0, i64 8, null}