When calculating 'nocapture' argument attributes, allow

the argument to be stored to an alloca by tracking uses
of the alloca.  This occurs 4 times (out of 7121, 0.05%)
in MultiSource/Applications, so may not be worth it.  On
the other hand, it is easy to do and fairly cheap.  The
functions it helps are: W_addcom and W_addlit in spiff;
process_args (argv) in d (make_dparser); ercPixConcealIMB
in JM/ldecod.

llvm-svn: 61570

1 files changed, 23 insertions, 0 deletions

diff --git a/llvm/test/Transforms/FunctionAttrs/2009-01-02-LocalStores.ll b/llvm/test/Transforms/FunctionAttrs/2009-01-02-LocalStores.ll
new file mode 100644
index 00000000000..17b443980b7
--- /dev/null
+++ b/llvm/test/Transforms/FunctionAttrs/2009-01-02-LocalStores.ll
@@ -0,0 +1,23 @@
+; 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
+
+	%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
+}