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[CaptureTracking] Support operand bundles conservatively

Summary:
Earlier CaptureTracking would assume all "interesting" operands to a
call or invoke were its arguments.  With operand bundles this is no
longer true.

Note: an earlier change got `doesNotCapture` working correctly with
operand bundles.

This change uses DSE to test the changes to CaptureTracking.  DSE is a
vehicle for testing only, and is not directly involved in this change.

Reviewers: reames, majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D14306

llvm-svn: 252095
This commit is contained in:
Sanjoy Das 2015-11-04 23:21:06 +00:00
parent c127f2db5e
commit b36621a78e
2 changed files with 32 additions and 2 deletions

View File

@ -253,8 +253,9 @@ void llvm::PointerMayBeCaptured(const Value *V, CaptureTracker *Tracker) {
// that loading a value from a pointer does not cause the pointer to be
// captured, even though the loaded value might be the pointer itself
// (think of self-referential objects).
CallSite::arg_iterator B = CS.arg_begin(), E = CS.arg_end();
for (CallSite::arg_iterator A = B; A != E; ++A)
CallSite::data_operand_iterator B =
CS.data_operands_begin(), E = CS.data_operands_end();
for (CallSite::data_operand_iterator A = B; A != E; ++A)
if (A->get() == V && !CS.doesNotCapture(A - B))
// The parameter is not marked 'nocapture' - captured.
if (Tracker->captured(U))

View File

@ -0,0 +1,29 @@
; RUN: opt -S -dse < %s | FileCheck %s
declare void @f()
declare noalias i8* @malloc(i32) nounwind
define void @test_0() {
; CHECK-LABEL: @test_0(
%m = call i8* @malloc(i32 24)
tail call void @f() [ "unknown"(i8* %m) ]
; CHECK: store i8 -19, i8* %m
store i8 -19, i8* %m
ret void
}
define i8* @test_1() {
; CHECK-LABEL: @test_1(
%m = call i8* @malloc(i32 24)
tail call void @f() [ "unknown"(i8* %m) ]
store i8 -19, i8* %m
tail call void @f()
store i8 101, i8* %m
; CHECK: tail call void @f() [ "unknown"(i8* %m) ]
; CHECK: store i8 -19, i8* %m
; CHECK: tail call void @f()
; CHECK: store i8 101, i8* %m
ret i8* %m
}