bits captured, but the pointer marked nocapture. In fact
I now recall that this problem is why only readnone functions
returning void were considered before! However keep a small
fix that was also in r70876: a readnone function returning
void can result in bits being captured if it unwinds, so
test for this.
llvm-svn: 71168
the readnone. Since MallocInst is scheduled for deletion
it doesn't seem worth doing anything more subtle, such as
having mayWriteToMemory return true for MallocInst.
llvm-svn: 71077
only capture their arguments by returning them or
throwing an exception or not based on the argument
value. Patch essentially by Frits van Bommel.
llvm-svn: 70876
was it not very helpful, it was also wrong! The problem
is shown in the testcase: the alloca might be passed to
a nocapture callee which dereferences it and returns the
original pointer. But because it was a nocapture call we
think we don't need to track its uses, but we do.
llvm-svn: 61876
the argument to be stored to an alloca by tracking uses
of the alloca. This occurs 4 times (out of 7121, 0.05%)
in MultiSource/Applications, so may not be worth it. On
the other hand, it is easy to do and fairly cheap. The
functions it helps are: W_addcom and W_addlit in spiff;
process_args (argv) in d (make_dparser); ercPixConcealIMB
in JM/ldecod.
llvm-svn: 61570
functions that don't write can't leak a pointer except through
the return value, so a void readonly function is implicitly nocapture.
Test these, and add a test that verifies that f1 calling f2 with an
otherwise dead pointer gets both of them marked nocapture.
llvm-svn: 61552
to work out (in a very simplistic way) which function
arguments (pointer arguments only) are only dereferenced
and so do not escape. Mark such arguments 'nocapture'.
llvm-svn: 61525
Duncan Sands