Displaying 5 results from an estimated 5 matches for "armisa".
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armisd
2016 Mar 25
0
NEON FP flags
...ctorizer would require fast-math flags in order to vectorize FP operations (similarly, gcc's man page says it requires -funsafe-math-optimizations for vectorization unless -mfpu=neon or similar is specified). In this context, this different-semantics query would return true if:
!(isDarwin OR ARMISA >= v8 OR fpMath == NEON)
and then we need to teach people to use -mfpu=neon ;)
I think this more-or-less matches what you've proposed. Is that right?
-Hal
P.S. Looking at gcc's man page, gcc seems to use -mfpu for ARM and -mfpmath for x86. Do we use -mfpmath for both?
----- Origina...
2016 Mar 22
2
NEON FP flags
On 22 March 2016 at 11:34, James Molloy <James.Molloy at arm.com> wrote:
> I don’t think this part is right. The denormal flag would have to be set by
> whatever code generates the FP instruction, which would be Clang’s codegen
> layer. So the if (Darwin) would be there, not in TTI.
Right, I meant the information to set/not set would be in TTI, not the
actual setting.
I don't
2016 Mar 25
3
NEON FP flags
...this context, this different-semantics query would return true if:
The semantics is indeed different, VFP is IEEE-754 compliant while
NEON is not. We don't want to stop the compiler from using VFP for FP
math, but we want to be cautious when using NEON in the same way..
> !(isDarwin OR ARMISA >= v8 OR fpMath == NEON)
>
> and then we need to teach people to use -mfpu=neon ;)
So, there's the catch. In GCC, -mfpu=neon means to use NEON, which is
not enabled by default, so the compiler assumes that the user is aware
that NEON FP is not IEEE compliant. I don't think that...
2016 Mar 22
2
NEON FP flags
...need to add a denormal flag to be set
if fpmath=neon/sse/etc on all FP instructions, and in the vectorizer,
we just test for that flag (which should also be set by fast-math).
The Darwin vs. Linux problem is, then, moved to the target transform
info, only setting the flag on ARM if...
isDarwin OR ARMISA >= v8 OR fastMath OR fpMath == NEON
Makes sense?
cheers,
--renato
2016 Mar 29
1
NEON FP flags
...would return
> > true if:
>
> The semantics is indeed different, VFP is IEEE-754 compliant while
> NEON is not. We don't want to stop the compiler from using VFP for FP
> math, but we want to be cautious when using NEON in the same way..
>
>
> > !(isDarwin OR ARMISA >= v8 OR fpMath == NEON)
> >
> > and then we need to teach people to use -mfpu=neon ;)
>
> So, there's the catch. In GCC, -mfpu=neon means to use NEON, which is
> not enabled by default, so the compiler assumes that the user is aware
> that NEON FP is not IEEE compli...