From 0df9abbd63a6cb3767d3ddf3b6c2f8ea8a4f6f7e Mon Sep 17 00:00:00 2001
From: Reid Kleckner <reid@kleckner.net>
Date: Mon, 21 Apr 2014 20:48:47 +0000
Subject: Fix PR7272 in -tailcallelim instead of the inliner

The -tailcallelim pass should be checking if byval or inalloca args can
be captured before marking calls as tail calls.  This was the real root
cause of PR7272.

With a better fix in place, revert the inliner change from r105255.  The
test case it introduced still passes and has been moved to
test/Transforms/Inline/byval-tail-call.ll.

Reviewers: chandlerc

Differential Revision: http://reviews.llvm.org/D3403

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206789 91177308-0d34-0410-b5e6-96231b3b80d8
---
 test/Transforms/Inline/2010-05-31-ByvalTailcall.ll | 25 --------------
 test/Transforms/Inline/byval-tail-call.ll          | 38 ++++++++++++++++++++++
 test/Transforms/TailCallElim/basic.ll              |  8 +++++
 3 files changed, 46 insertions(+), 25 deletions(-)
 delete mode 100644 test/Transforms/Inline/2010-05-31-ByvalTailcall.ll
 create mode 100644 test/Transforms/Inline/byval-tail-call.ll

(limited to 'test')

diff --git a/test/Transforms/Inline/2010-05-31-ByvalTailcall.ll b/test/Transforms/Inline/2010-05-31-ByvalTailcall.ll
deleted file mode 100644
index 07ea5fc6cc..0000000000
--- a/test/Transforms/Inline/2010-05-31-ByvalTailcall.ll
+++ /dev/null
@@ -1,25 +0,0 @@
-; RUN: opt < %s -tailcallelim -inline -instcombine -dse -S | FileCheck %s
-; PR7272
-
-; When inlining through a byval call site, the inliner creates allocas which may
-; be used by inlined calls, so any inlined calls need to have their 'tail' flags
-; cleared.  If not then you can get nastiness like with this testcase, where the
-; (inlined) call to 'ext' in 'foo' was being passed an uninitialized value.
-
-target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32"
-target triple = "i386-pc-linux-gnu"
-
-declare void @ext(i32*)
-
-define void @bar(i32* byval %x) {
-  call void @ext(i32* %x)
-  ret void
-}
-
-define void @foo(i32* %x) {
-; CHECK-LABEL: define void @foo(
-; CHECK: llvm.lifetime.start
-; CHECK: store i32 %2, i32* %x
-  call void @bar(i32* byval %x)
-  ret void
-}
diff --git a/test/Transforms/Inline/byval-tail-call.ll b/test/Transforms/Inline/byval-tail-call.ll
new file mode 100644
index 0000000000..3a8906aa21
--- /dev/null
+++ b/test/Transforms/Inline/byval-tail-call.ll
@@ -0,0 +1,38 @@
+; RUN: opt < %s -tailcallelim -inline -instcombine -dse -S | FileCheck %s
+; PR7272
+
+; Calls that capture byval parameters cannot be marked as tail calls. Other
+; tails that don't capture byval parameters can still be tail calls.
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32"
+target triple = "i386-pc-linux-gnu"
+
+declare void @ext(i32*)
+
+define void @bar(i32* byval %x) {
+  call void @ext(i32* %x)
+  ret void
+}
+
+define void @foo(i32* %x) {
+; CHECK-LABEL: define void @foo(
+; CHECK: llvm.lifetime.start
+; CHECK: store i32 %2, i32* %x
+  call void @bar(i32* byval %x)
+  ret void
+}
+
+define internal void @qux(i32* byval %x) {
+  call void @ext(i32* %x)
+  tail call void @ext(i32* null)
+  ret void
+}
+define void @frob(i32* %x) {
+; CHECK-LABEL: define void @frob(
+; CHECK: alloca i32
+; CHECK: {{^ *}}call void @ext(
+; CHECK: tail call void @ext(i32* null)
+; CHECK: ret void
+  tail call void @qux(i32* byval %x)
+  ret void
+}
diff --git a/test/Transforms/TailCallElim/basic.ll b/test/Transforms/TailCallElim/basic.ll
index 35420ab08c..5582ee33ed 100644
--- a/test/Transforms/TailCallElim/basic.ll
+++ b/test/Transforms/TailCallElim/basic.ll
@@ -143,3 +143,11 @@ cond_false:
   call void @noarg()
   ret i32* null
 }
+
+; Don't tail call if a byval arg is captured.
+define void @test9(i32* byval %a) {
+; CHECK-LABEL: define void @test9(
+; CHECK: {{^ *}}call void @use(
+  call void @use(i32* %a)
+  ret void
+}
-- 
cgit v1.2.3