Look through phi nodes and select instructions when
calculating nocapture attributes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61535 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/IPO/FunctionAttrs.cpp b/lib/Transforms/IPO/FunctionAttrs.cpp
index 1824a71..52be0c9 100644
--- a/lib/Transforms/IPO/FunctionAttrs.cpp
+++ b/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -225,9 +225,14 @@
continue;
}
- if (isa<BitCastInst>(I) || isa<GetElementPtrInst>(I)) {
- // Type conversion or calculating an offset. Does not escape if the new
- // value doesn't.
+ if (isa<BitCastInst>(I) || isa<GetElementPtrInst>(I) ||
+ isa<PHINode>(I) || isa<SelectInst>(I)) {
+ // Type conversion, calculating an offset, or merging values.
+ // The original value does not escape via this if the new value doesn't.
+ // Note that in the case of a select instruction it is important that
+ // the value not be used as the condition, since otherwise one bit of
+ // information might escape. It cannot be the condition because it has
+ // the wrong type.
for (Instruction::use_iterator UI = I->use_begin(), UE = I->use_end();
UI != UE; ++UI) {
Use *U = &UI.getUse();
diff --git a/test/Transforms/FunctionAttrs/2008-12-31-NoCapture.ll b/test/Transforms/FunctionAttrs/2008-12-31-NoCapture.ll
index 6d2ca1e..86feb43 100644
--- a/test/Transforms/FunctionAttrs/2008-12-31-NoCapture.ll
+++ b/test/Transforms/FunctionAttrs/2008-12-31-NoCapture.ll
@@ -1,34 +1,41 @@
-; RUN: llvm-as < %s | opt -functionattrs | llvm-dis | not grep {@c.*nocapture}
-; RUN: llvm-as < %s | opt -functionattrs | llvm-dis | grep nocapture | count 3
+; RUN: llvm-as < %s | opt -functionattrs | llvm-dis | not grep {nocapture *%%q}
+; RUN: llvm-as < %s | opt -functionattrs | llvm-dis | grep {nocapture *%%p} | count 3
@g = global i32* null ; <i32**> [#uses=1]
-define i32* @c1(i32* %p) {
- ret i32* %p
+define i32* @c1(i32* %q) {
+ ret i32* %q
}
-define void @c2(i32* %p) {
- store i32* %p, i32** @g
+define void @c2(i32* %q) {
+ store i32* %q, i32** @g
ret void
}
-define void @c3(i32* %p) {
- call void @c2(i32* %p)
+define void @c3(i32* %q) {
+ call void @c2(i32* %q)
ret void
}
-define i32 @nc1(i32* %p) {
- %tmp = bitcast i32* %p to i32* ; <i32*> [#uses=2]
- %val = load i32* %tmp ; <i32> [#uses=1]
+define i32 @nc1(i32* %q, i32* %p, i1 %b) {
+e:
+ br label %l
+l:
+ %x = phi i32* [ %p, %e ]
+ %y = phi i32* [ %q, %e ]
+ %tmp = bitcast i32* %x to i32* ; <i32*> [#uses=2]
+ %tmp2 = select i1 %b, i32* %tmp, i32* %y
+ %val = load i32* %tmp2 ; <i32> [#uses=1]
store i32 0, i32* %tmp
+ store i32* %y, i32** @g
ret i32 %val
}
-define void @nc2(i32* %p) {
- %1 = call i32 @nc1(i32* %p) ; <i32> [#uses=0]
+define void @nc2(i32* %p, i32* %q) {
+ %1 = call i32 @nc1(i32* %q, i32* %p, i1 0) ; <i32> [#uses=0]
ret void
}
-define void @nc3(void ()* %f) {
- call void %f()
+define void @nc3(void ()* %p) {
+ call void %p()
ret void
}