When ‘ffast-math’ is set, ffp-contract is altered this way:
-ffast-math/ Ofast -> ffp-contract=fast
-fno-fast-math -> if ffp-contract= fast then ffp-contract=on else
ffp-contract unchanged
This differs from gcc which doesn’t connect the two options.
Connecting these two options in clang, resulted in spurious warnings
when the user combines these two options -ffast-math -fno-fast-math; see
issue https://github.com/llvm/llvm-project/issues/54625.
The issue is that the ‘ffast-math’ option is an on/off flag, but the
‘ffp-contract’ is an on/off/fast flag. So when ‘fno-fast-math’ is used
there is no obvious value for ‘ffp-contract’. What should the value of
ffp-contract be for -ffp-contract=fast -fno-fast-math and -ffast-math
-ffp-contract=fast -fno-fast-math? The current logic sets ffp-contract
back to on in these cases. This doesn’t take into account that the value
of ffp-contract is modified by an explicit ffp-contract` option.
This patch is proposing a set of rules to apply when ffp-contract',
ffast-math and fno-fast-math are combined. These rules would give the
user the expected behavior and no diagnostic would be needed.
See RFC
https://discourse.llvm.org/t/rfc-making-ffast-math-option-unrelated-to-ffp-contract-option/61912
This adds -no-opaque-pointers to clang tests whose output will
change when opaque pointers are enabled by default. This is
intended to be part of the migration approach described in
https://discourse.llvm.org/t/enabling-opaque-pointers-by-default/61322/9.
The patch has been produced by replacing %clang_cc1 with
%clang_cc1 -no-opaque-pointers for tests that fail with opaque
pointers enabled. Worth noting that this doesn't cover all tests,
there's a remaining ~40 tests not using %clang_cc1 that will need
a followup change.
Differential Revision: https://reviews.llvm.org/D123115
Change the ffp-model=precise to enables -ffp-contract=on (previously
-ffp-model=precise enabled -ffp-contract=fast). This is a follow-up
to Andy Kaylor's comments in the llvm-dev discussion "Floating Point
semantic modes". From the same email thread, I put Andy's distillation
of floating point options and floating point modes into UsersManual.rst
Also fixes bugs.llvm.org/show_bug.cgi?id=50222
I had to revert this a few times because of failures on the x86-64
buildbot but I think we finally have that fixed by LNT/79f2b03c51.
Reviewed By: rjmccall, andrew.kaylor
Differential Revision: https://reviews.llvm.org/D74436
Change the ffp-model=precise to enables -ffp-contract=on (previously
-ffp-model=precise enabled -ffp-contract=fast). This is a follow-up
to Andy Kaylor's comments in the llvm-dev discussion "Floating Point
semantic modes". From the same email thread, I put Andy's distillation
of floating point options and floating point modes into UsersManual.rst
Also fixes bugs.llvm.org/show_bug.cgi?id=50222
Reviewed By: rjmccall, andrew.kaylor
Differential Revision: https://reviews.llvm.org/D74436
This reverts commit a1449a10db.
Seems like my changes to LNT had no effect -- puzzled.
The 21 tests pass on my sandbox with the clang patch but are
failing in exec time in the bot
This patch changes the ffp-model=precise to enables -ffp-contract=on
(previously -ffp-model=precise enabled -ffp-contract=fast). This is a
follow-up to Andy Kaylor's comments in the llvm-dev discussion
"Floating Point semantic modes". From the same email thread, I put
Andy's distillation of floating point options and floating point modes
into UsersManual.rst
Differential Revision: https://reviews.llvm.org/D74436
This patch changes the ffp-model=precise to enables -ffp-contract=on
(previously -ffp-model=precise enabled -ffp-contract=fast). This is a
follow-up to Andy Kaylor's comments in the llvm-dev discussion
"Floating Point semantic modes". From the same email thread, I put
Andy's distillation of floating point options and floating point modes
into UsersManual.rst
Differential Revision: https://reviews.llvm.org/D74436
Clang will now honor the FP_CONTRACT pragma and emit LLVM
fmuladd intrinsics for expressions of the form A * B + C (when they occur in a
single statement).
llvm-svn: 164989
Zahira Ammarguellat