From a6cbeb82b6689a1956d20c22c2e431388bdc5602 Mon Sep 17 00:00:00 2001
From: Sanjoy Das <sanjoy@playingwithpointers.com>
Date: Wed, 4 Nov 2015 23:21:06 +0000
Subject: [PATCH] [CaptureTracking] Support operand bundles conservatively

Summary:
Earlier CaptureTracking would assume all "interesting" operands to a
call or invoke were its arguments.  With operand bundles this is no
longer true.

Note: an earlier change got `doesNotCapture` working correctly with
operand bundles.

This change uses DSE to test the changes to CaptureTracking.  DSE is a
vehicle for testing only, and is not directly involved in this change.

Reviewers: reames, majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D14306

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252095 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Analysis/CaptureTracking.cpp   |  5 +++--
 test/Feature/OperandBundles/dse.ll | 29 +++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 2 deletions(-)
 create mode 100644 test/Feature/OperandBundles/dse.ll

diff --git a/lib/Analysis/CaptureTracking.cpp b/lib/Analysis/CaptureTracking.cpp
index de5ec29c857..230a380c4bf 100644
--- a/lib/Analysis/CaptureTracking.cpp
+++ b/lib/Analysis/CaptureTracking.cpp
@@ -253,8 +253,9 @@ void llvm::PointerMayBeCaptured(const Value *V, CaptureTracker *Tracker) {
       // that loading a value from a pointer does not cause the pointer to be
       // captured, even though the loaded value might be the pointer itself
       // (think of self-referential objects).
-      CallSite::arg_iterator B = CS.arg_begin(), E = CS.arg_end();
-      for (CallSite::arg_iterator A = B; A != E; ++A)
+      CallSite::data_operand_iterator B =
+        CS.data_operands_begin(), E = CS.data_operands_end();
+      for (CallSite::data_operand_iterator A = B; A != E; ++A)
         if (A->get() == V && !CS.doesNotCapture(A - B))
           // The parameter is not marked 'nocapture' - captured.
           if (Tracker->captured(U))
diff --git a/test/Feature/OperandBundles/dse.ll b/test/Feature/OperandBundles/dse.ll
new file mode 100644
index 00000000000..cc5647a2fa0
--- /dev/null
+++ b/test/Feature/OperandBundles/dse.ll
@@ -0,0 +1,29 @@
+; RUN: opt -S -dse < %s | FileCheck %s
+
+declare void @f()
+declare noalias i8* @malloc(i32) nounwind
+
+define void @test_0() {
+; CHECK-LABEL: @test_0(
+  %m = call i8* @malloc(i32 24)
+  tail call void @f() [ "unknown"(i8* %m) ]
+; CHECK: store i8 -19, i8* %m
+  store i8 -19, i8* %m
+  ret void
+}
+
+define i8* @test_1() {
+; CHECK-LABEL: @test_1(
+  %m = call i8* @malloc(i32 24)
+  tail call void @f() [ "unknown"(i8* %m) ]
+  store i8 -19, i8* %m
+  tail call void @f()
+  store i8 101, i8* %m
+
+; CHECK: tail call void @f() [ "unknown"(i8* %m) ]
+; CHECK: store i8 -19, i8* %m
+; CHECK: tail call void @f()
+; CHECK: store i8 101, i8* %m
+
+  ret i8* %m
+}
-- 
2.34.1