Change CaptureTracking to pass a Use* instead of a Value* when a value is

captured. This allows the tracker to look at the specific use, which may be
especially interesting for function calls.

Use this to fix 'nocapture' deduction in FunctionAttrs. The existing one does
not iterate until a fixpoint and does not guarantee that it produces the same
result regardless of iteration order. The new implementation builds up a graph
of how arguments are passed from function to function, and uses a bottom-up walk
on the argument-SCCs to assign nocapture. This gets us nocapture more often, and
does so rather efficiently and independent of iteration order.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147327 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 62 insertions, 1 deletions

diff --git a/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll b/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll
index 8fb5ffffba..1ac59278e7 100644
--- a/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll
+++ b/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll
@@ -24,7 +24,7 @@ define void @test0_no(i32* %p) nounwind {
 ; Add the readonly attribute, since there's just a call to a function which 
 ; TBAA says doesn't modify any memory.
 
-; CHECK: define void @test1_yes(i32* %p) nounwind readonly {
+; CHECK: define void @test1_yes(i32* nocapture %p) nounwind readonly {
 define void @test1_yes(i32* %p) nounwind {
   call void @callee(i32* %p), !tbaa !1
   ret void
diff --git a/test/Transforms/FunctionAttrs/nocapture.ll b/test/Transforms/FunctionAttrs/nocapture.ll
index fa699b4deb..3027acd35c 100644
--- a/test/Transforms/FunctionAttrs/nocapture.ll
+++ b/test/Transforms/FunctionAttrs/nocapture.ll
@@ -115,3 +115,64 @@ define void @nc5(void (i8*)* %f, i8* %p) {
 	call void %f(i8* nocapture %p)
 	ret void
 }
+
+; CHECK: define void @test1_1(i8* nocapture %x1_1, i8* %y1_1)
+define void @test1_1(i8* %x1_1, i8* %y1_1) {
+  call i8* @test1_2(i8* %x1_1, i8* %y1_1)
+  store i32* null, i32** @g
+  ret void
+}
+
+; CHECK: define i8* @test1_2(i8* nocapture %x1_2, i8* %y1_2)
+define i8* @test1_2(i8* %x1_2, i8* %y1_2) {
+  call void @test1_1(i8* %x1_2, i8* %y1_2)
+  store i32* null, i32** @g
+  ret i8* %y1_2
+}
+
+; CHECK: define void @test2(i8* nocapture %x2)
+define void @test2(i8* %x2) {
+  call void @test2(i8* %x2)
+  store i32* null, i32** @g
+  ret void
+}
+
+; CHECK: define void @test3(i8* nocapture %x3, i8* nocapture %y3, i8* nocapture %z3)
+define void @test3(i8* %x3, i8* %y3, i8* %z3) {
+  call void @test3(i8* %z3, i8* %y3, i8* %x3)
+  store i32* null, i32** @g
+  ret void
+}
+
+; CHECK: define void @test4_1(i8* %x4_1)
+define void @test4_1(i8* %x4_1) {
+  call i8* @test4_2(i8* %x4_1, i8* %x4_1, i8* %x4_1)
+  store i32* null, i32** @g
+  ret void
+}
+
+; CHECK: define i8* @test4_2(i8* nocapture %x4_2, i8* %y4_2, i8* nocapture %z4_2)
+define i8* @test4_2(i8* %x4_2, i8* %y4_2, i8* %z4_2) {
+  call void @test4_1(i8* null)
+  store i32* null, i32** @g
+  ret i8* %y4_2
+}
+
+declare i8* @test5_1(i8* %x5_1)
+
+; CHECK: define void @test5_2(i8* %x5_2)
+define void @test5_2(i8* %x5_2) {
+  call i8* @test5_1(i8* %x5_2)
+  store i32* null, i32** @g
+  ret void
+}
+
+declare void @test6_1(i8* %x6_1, i8* nocapture %y6_1, ...)
+
+; CHECK: define void @test6_2(i8* %x6_2, i8* nocapture %y6_2, i8* %z6_2)
+define void @test6_2(i8* %x6_2, i8* %y6_2, i8* %z6_2) {
+  call void (i8*, i8*, ...)* @test6_1(i8* %x6_2, i8* %y6_2, i8* %z6_2)
+  store i32* null, i32** @g
+  ret void
+}
+