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llvm-mirror/test/Analysis/Lint/tail-call-byval.ll
Mikael Holmen 37eaf65cb9 [Lint] Don't warn about passing alloca'd value to tail call if using byval
Summary:
This fixes PR35241.

When using byval, the data is effectively copied as part of the call
anyway, so the pointer returned by the alloca will not be leaked to the
callee and thus there is no reason to issue a warning.

Reviewers: rnk

Reviewed By: rnk

Subscribers: Ka-Ka, llvm-commits

Differential Revision: https://reviews.llvm.org/D40009

llvm-svn: 318279
2017-11-15 07:46:48 +00:00

34 lines
796 B
LLVM

; RUN: opt < %s -lint -disable-output 2>&1 | FileCheck %s
%s = type { i8 }
declare void @f1(%s*)
define void @f2() {
entry:
%c = alloca %s
tail call void @f1(%s* %c)
ret void
}
; Lint should complain about the tail call passing the alloca'd value %c to f1.
; CHECK: Undefined behavior: Call with "tail" keyword references alloca
; CHECK-NEXT: tail call void @f1(%s* %c)
declare void @f3(%s* byval)
define void @f4() {
entry:
%c = alloca %s
tail call void @f3(%s* byval %c)
ret void
}
; Lint should not complain about passing the alloca'd %c since it's passed
; byval, effectively copying the data to the stack instead of leaking the
; pointer itself.
; CHECK-NOT: Undefined behavior: Call with "tail" keyword references alloca
; CHECK-NOT: tail call void @f3(%s* byval %c)