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Look through phi nodes and select instructions when

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calculating nocapture attributes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61535 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Duncan Sands 2008-12-31 20:21:34 +00:00
parent 587cbd0058
commit 1010941954
2 changed files with 30 additions and 18 deletions
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11
lib/Transforms/IPO/FunctionAttrs.cpp
View File

@ -225,9 +225,14 @@ bool FunctionAttrs::isCaptured(Function &F, Value *V) {
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();

37
test/Transforms/FunctionAttrs/2008-12-31-NoCapture.ll
View File

@ -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
}