From d080ee893d1b5b254af2f3ec4a171f5d9426c4d8 Mon Sep 17 00:00:00 2001
From: Sanjoy Das <sanjoy@playingwithpointers.com>
Date: Sat, 19 Dec 2015 22:40:28 +0000
Subject: [PATCH] Nonnull elements in OperandBundleCallSites are not all
 Instructions

`CloneAndPruneIntoFromInst` sometimes RAUW's dead instructions with
`undef` before erasing them (to avoid deleting instructions that still
have uses).  This changes the `WeakVH` in `OperandBundleCallSites` to
hold an `undef`, and we need to guard for this situation in eventuality
in `llvm::InlineFunction`.

llvm-svn: 256110
---
 include/llvm/Transforms/Utils/Cloning.h |  4 +--
 lib/Transforms/Utils/InlineFunction.cpp |  5 ++--
 test/Transforms/Inline/deopt-bundles.ll | 36 +++++++++++++++++++++++++
 3 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/include/llvm/Transforms/Utils/Cloning.h b/include/llvm/Transforms/Utils/Cloning.h
index d1a5fdeaddc..92a1d52f101 100644
--- a/include/llvm/Transforms/Utils/Cloning.h
+++ b/include/llvm/Transforms/Utils/Cloning.h
@@ -75,8 +75,8 @@ struct ClonedCodeInfo {
   bool ContainsDynamicAllocas;
 
   /// All cloned call sites that have operand bundles attached are appended to
-  /// this vector.  This vector may contain nulls if some of the originally
-  /// inserted callsites were DCE'ed after they were cloned.
+  /// this vector.  This vector may contain nulls or undefs if some of the
+  /// originally inserted callsites were DCE'ed after they were cloned.
   std::vector<WeakVH> OperandBundleCallSites;
 
   ClonedCodeInfo() : ContainsCalls(false), ContainsDynamicAllocas(false) {}
diff --git a/lib/Transforms/Utils/InlineFunction.cpp b/lib/Transforms/Utils/InlineFunction.cpp
index db2cacd4739..14574119b9a 100644
--- a/lib/Transforms/Utils/InlineFunction.cpp
+++ b/lib/Transforms/Utils/InlineFunction.cpp
@@ -1196,9 +1196,8 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
       SmallVector<OperandBundleDef, 2> OpDefs;
 
       for (auto &VH : InlinedFunctionInfo.OperandBundleCallSites) {
-        if (!VH) continue;  // instruction was DCE'd after being cloned
-
-        Instruction *I = cast<Instruction>(VH);
+        Instruction *I = dyn_cast_or_null<Instruction>(VH);
+        if (!I) continue;  // instruction was DCE'd or RAUW'ed to undef
 
         OpDefs.clear();
 
diff --git a/test/Transforms/Inline/deopt-bundles.ll b/test/Transforms/Inline/deopt-bundles.ll
index 1acbb2f0585..3e3c52f7d2d 100644
--- a/test/Transforms/Inline/deopt-bundles.ll
+++ b/test/Transforms/Inline/deopt-bundles.ll
@@ -162,6 +162,42 @@ define i32 @caller_7() {
   ret i32 %x
 }
 
+define i32 @callee_8(i1 %val) alwaysinline personality i8 3 {
+; We want something that PruningFunctionCloner is not smart enough to
+; recognize, but can be recognized by recursivelySimplifyInstruction.
+
+ entry:
+  br i1 %val, label %check, label %precheck
+
+ precheck:
+  br label %check
+
+ check:
+  %p = phi i1 [ %val, %entry ], [ true, %precheck ]
+  br i1 %p, label %do.not, label %do
+
+ do.not:
+  ret i32 0
+
+ do:
+  %phi = phi i32 [ 0, %check ], [ %v, %do ]
+  %v = call fastcc i32 @g.fastcc() [ "deopt"(i32 0, i32 1), "foo"(double 0.0) ]
+  %ic = icmp eq i32 %v, 42
+  br i1 %ic, label %do, label %done
+
+ done:
+  ret i32 %phi
+}
+
+define i32 @caller_8() {
+; CHECK-LABEL: @caller_8(
+ entry:
+; CHECK-NOT: call fastcc i32 @g.fastcc()
+; CHECK: ret i32 0
+  %x = call i32 @callee_8(i1 true) [ "deopt"(i32 7) ]
+  ret i32 %x
+}
+
 attributes #0 = { "foo"="bar" }
 
 ; CHECK: attributes #[[FOO_BAR_ATTR_IDX]] = { "foo"="bar" }