LGTM!

rebased with the master.

addressed @mhorne comments.

@asb and @luismarques do you suggest anything here ?

ping?

ping?

addressed @mhorne and @MaskRay concerns.

rebased and cleaned up the diff.

In D82171#2103042, @tambre wrote:

D77505 broke a bunch of bots. This fixes the regression.

I lack commit privileges. Please land as "Raul Tambre <raul@tambre.ee>"

In D77505#2102613, @tambre wrote:

Please commit this for me in case no one else has objections. I lack commit privileges.

Addressed @efriedma comments.
added test for strictfp.

thanks @mhorne for reviewing.
addressed your comments.

ping?

ping?

Rebased

addressed @luismarques concerns.
This patch extends soft float case .

enhanced and more testcases.

I do not have commit access,
can someone commit this for me?

In D80465#2060164, @luismarques wrote:

LGTM. But please give it some time for other people to chime in before you merge, they may disagree with this .inc approach.
I'm approving this assuming the generic test is actually ran against this implementation. @kamleshbhalui did you verify that was the case?

cleanup

In D80690#2060505, @ldionne wrote:

@kamleshbhalui Just to be clear -- you need libunwind approval before you can submit a patch that touches libunwind. If you just wanted to iterate on this privately it's OK, but you'll need approval from the group before submitting.

restructured the file. so it can be picked by lit test.

defined _LIBUNWIND_CURSOR_SIZE
for all these below variants
ILP32 + "f" : xlen = 32, flen = 32 ===> 39
ILP32 + "fd" : xlen = 32, flen = 64 ===>55
LP64 + "f" : xlen = 64, flen = 32 ====>60
LP64 + "fd" : xlen = 64, flen = 64 ====>76 (was already done.)

addressed @luismarques comments.

Addressed @luismarques concerns.

In D80465#2057408, @MaskRay wrote:

In D80465#2051978, @kamleshbhalui wrote:

In D80465#2051925, @MaskRay wrote:

You can generalize muldi3.c to implement __mulsi3.

looks like no one uses mulsi3 other than riscv32 which already has target specific implementation.
This patch adds muldi3 target-specific implementation for riscv64 to get rid of problem shown in summary.

Still uneasy with the assembly implementation. .c works as well, doesn't it?

ping?

-ftrapping-math will do the work.
so abandoning it.

fixed failing testcase.

In D77505#2051950, @tambre wrote:

Borrow useful things from D78427:

• A test
• Version guard
• Double include test

Rebased on master.

added CMakeLists.txt change for riscv64.

In D80465#2051925, @MaskRay wrote:

You can generalize muldi3.c to implement __mulsi3.

duplicate of D77505

thanks @curdeius for pointing this.
Hi @tambre
I was unaware of this work and ended of doing same work.
please take things from here D78427 which seems reasonable.
and update the this review. so i can cancel my review.

In D79504#2029267, @ldionne wrote:

What name and email do you want this committed with?

I do not have commit access.

Incorporated @curdeius suggestion.

Addressed @rsmith concerns.

Thanks for review @curdeius
clang-formatted the diff.
and used http://mpmath.org/ for calculating all constants.

Thanks for the review @curdeius.
addressed your concerns.

ping?

changed value to __value

Thanks for review.
added cxx2a _statu.html

Cleanup and
Add one more test.

Added test

Thanks, LGTM.

Replaced by D77912

for this input
a=3325549423267495579 ,b=2351357301745665781
and compiled with -O2 with clang-9.
it takes 299 ns.
while D77744 takes only 91ns.

here is compiler detils i tried upon.

it's still less optimal.

Code review in D77744 is performance-wise better than this.

Thanks @lenary for review.
I do not have commit access,
please commit this when you get time.

nit test

nits and updated test.

Added rv32 run line.

nit and Added the tests.