Remove alloca tracking from nocapture analysis. Not only

was it not very helpful, it was also wrong!  The problem
is shown in the testcase: the alloca might be passed to
a nocapture callee which dereferences it and returns the
original pointer.  But because it was a nocapture call we
think we don't need to track its uses, but we do.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61876 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 18 deletions

diff --git a/test/Transforms/FunctionAttrs/2009-01-02-LocalStores.ll b/test/Transforms/FunctionAttrs/2009-01-02-LocalStores.ll
index 17b4439..68a232f 100644
--- a/test/Transforms/FunctionAttrs/2009-01-02-LocalStores.ll
+++ b/test/Transforms/FunctionAttrs/2009-01-02-LocalStores.ll
@@ -1,23 +1,14 @@
 ; RUN: llvm-as < %s | opt -functionattrs | llvm-dis | not grep {nocapture *%%q}
 ; RUN: llvm-as < %s | opt -functionattrs | llvm-dis | grep {nocapture *%%p}
 
-@g = external global i32**
-
-define i32 @f(i32* %p, i32* %q) {
-	%a1 = alloca i32*
-	%a2 = alloca i32**
-	store i32* %p, i32** %a1
-	store i32** %a1, i32*** %a2
-	%reload1 = load i32*** %a2
-	%reload2 = load i32** %reload1
-	%load_p = load i32* %reload2
-	store i32 0, i32* %reload2
+define i32* @a(i32** %p) {
+	%tmp = load i32** %p
+	ret i32* %tmp
+}
 
-	%b1 = alloca i32*
-	%b2 = alloca i32**
-	store i32* %q, i32** %b1
-	store i32** %b1, i32*** %b2
-	%reload3 = load i32*** %b2
-	store i32** %reload3, i32*** @g
-	ret i32 %load_p
+define i32* @b(i32 *%q) {
+	%mem = alloca i32*
+	store i32* %q, i32** %mem
+	%tmp = call i32* @a(i32** %mem)
+	ret i32* %tmp
 }