The special lowering for __builtin_mul_overflow introduced in r320902
fixed an ICE seen when passing mixed-sign operands to the builtin.
This patch extends the special lowering to cover mixed-width, mixed-sign
operands. In a few common scenarios, calls to muloti4 will no longer be
emitted.
This should address the latest comments in PR34920 and work around the
link failure seen in:
https://bugzilla.redhat.com/show_bug.cgi?id=1657544
Testing:
- check-clang
- A/B output comparison with: https://gist.github.com/vedantk/3eb9c88f82e5c32f2e590555b4af5081
Differential Revision: https://reviews.llvm.org/D55843
llvm-svn: 349542
The tests that failed on a windows host have been fixed.
Original message:
Start setting dso_local for COFF.
With this there are still some GVs where we don't set dso_local
because setGVProperties is never called. I intend to fix that in
followup commits. This is just the bare minimum to teach
shouldAssumeDSOLocal what it should do for COFF.
llvm-svn: 325940
With this there are still some GVs where we don't set dso_local
because setGVProperties is never called. I intend to fix that in
followup commits. This is just the bare minimum to teach
shouldAssumeDSOLocal what it should do for COFF.
llvm-svn: 325915
r320902 fixed the IRGen for some types of checked multiplications. It
did not handle unsigned overflow correctly in the case where the signed
operand is negative (PR35750).
Eli pointed out that on overflow, the result must be equal to the unique
value that is equivalent to the mathematically-correct result modulo two
raised to the k power, where k is the number of bits in the result type.
This patch fixes the specialized IRGen from r320902 accordingly.
Testing: Apart from check-clang, I modified the test harness from
r320902 to validate the results of all multiplications -- not just the
ones which don't overflow:
https://gist.github.com/vedantk/3eb9c88f82e5c32f2e590555b4af5081
llvm.org/PR35750, rdar://34963321
Differential Revision: https://reviews.llvm.org/D41717
llvm-svn: 321771
This patch introduces a specialized way to lower overflow-checked
multiplications with mixed-sign operands. This fixes link failures and
ICEs on code like this:
void mul(int64_t a, uint64_t b) {
int64_t res;
__builtin_mul_overflow(a, b, &res);
}
The generic checked-binop irgen would use a 65-bit multiplication
intrinsic here, which requires runtime support for _muloti4 (128-bit
multiplication), and therefore fails to link on i386. To get an ICE
on x86_64, change the example to use __int128_t / __uint128_t.
Adding runtime and backend support for 65-bit or 129-bit checked
multiplication on all of our supported targets is infeasible.
This patch solves the problem by using simpler, specialized irgen for
the mixed-sign case.
llvm.org/PR34920, rdar://34963321
Testing: Apart from check-clang, I compared the output from this fairly
comprehensive test driver using unpatched & patched clangs:
https://gist.github.com/vedantk/3eb9c88f82e5c32f2e590555b4af5081
Differential Revision: https://reviews.llvm.org/D41149
llvm-svn: 320902
This will enable users in security critical applications to perform
checked-arithmetic in a fast safe manner that is amenable to c.
Tests/an update to Language Extensions is included as well.
rdar://13421498.
llvm-svn: 184497
Vedant Kumar