search for: fp_abstolerance

...If you're using -Ofast, however, that would explain it. I recommend looking at -O3 vs -O0 and make sure those are the same. -Ofast enables -ffast-math, which can legitimately cause differences. > The following tests pass at "-O3" and "-O3 -ffp-contract=on" compared with FP_ABSTOLERANCE=1e-5 against "-O0 -ffp-contract=off": polybench/linear-algebra/kernels/symm polybench/linear-algebra/solvers/gramschmidt polybench/stencils/seidel-2d The output of these 3 tests from "-O0 -ffp-contract=off" also matches the reference output. The following 2 tests still requir...

...-contract=on >> > -Ofast -ffp-contract=off >> >> Let's separate completely FP-contract and fast-math. They're >> different >> things and need different solutions. >> >> >> > if(TEST_SUITE_USES_FAST_MATH) >> > add_definitions(-DFP_ABSTOLERANCE=1e0) >> > else() >> > add_definitions(-DFP_ABSTOLERANCE=1e-5) >> > endif() >> >> This doesn't make sense. If my program decreased precision by 5 >> orders >> of magnitude with -ffast-math, I'd be *very* worried. > > Is this an absol...

On Fri, Oct 14, 2016 at 6:10 PM, Hal Finkel <hfinkel at anl.gov> wrote: >> polybench/linear-algebra/kernels/symm, FP_ABSTOLERANCE=1e1 >> polybench/linear-algebra/solvers/gramschmidt, FP_ABSTOLERANCE=1e0 >> What should be a good relative tolerance to set for these two tests? > > What's the minimum relative tolerance that you need for them to pass? Setting FP_ABSTOLERANCE=1e-5, the two tests are passing w...

...[i][j] = beta * C[i][j] + alpha * A[i][i] * B[i][j] + alpha * acc; } } Compiling this kernel with __attribute__((optnone)) and outputing the contents of the C[][] array does not match the reference output. Furthermore, compiling this kernel at -Ofast and comparing against -O0 only passes for FP_ABSTOLERANCE=10. All the 10 other polybench tests that I have transformed to check FP are passing at FP_ABSTOLERANCE=1e-5 (and most likely they could pass at an even more reduced tolerance.) The symm benchmark seems to accumulate all the errors as it is a big reduction from the first elements of the C[][] arra...

On 12 October 2016 at 14:26, Sebastian Pop <sebpop.llvm at gmail.com> wrote: > Correct me if I misunderstood: you would be ok changing the > reference output to exactly match the output of "-O0 -ffp-contract=off". No, that's not at all what I said. Matching identical outputs to FP tests makes no sense because there's *always* an error bar. The output of O0, O1, O2,

...> -O0 -ffp-contract=on > > They are not passing at: > -Ofast -ffp-contract=on > -Ofast -ffp-contract=off Let's separate completely FP-contract and fast-math. They're different things and need different solutions. > if(TEST_SUITE_USES_FAST_MATH) > add_definitions(-DFP_ABSTOLERANCE=1e0) > else() > add_definitions(-DFP_ABSTOLERANCE=1e-5) > endif() This doesn't make sense. If my program decreased precision by 5 orders of magnitude with -ffast-math, I'd be *very* worried. I hope that fast-math in Clang isn't that broken, so that's probably to do with...

On Wed, Oct 12, 2016 at 10:28 AM, Hal Finkel <hfinkel at anl.gov> wrote: > ----- Original Message ----- >> From: "Renato Golin" <renato.golin at linaro.org> >> To: "Hal Finkel" <hfinkel at anl.gov> >> Cc: "Sebastian Paul Pop" <s.pop at samsung.com>, "llvm-dev" <llvm-dev at lists.llvm.org>, "Matthias

On Thu, Oct 20, 2016 at 11:12 AM, Renato Golin <renato.golin at linaro.org> wrote: > On 20 October 2016 at 16:05, Sebastian Pop <sebpop.llvm at gmail.com> wrote: >> Setting FP_ABSTOLERANCE=1e-5, the two tests are passing >> when compiled with -Ofast for the following relative tolerance: >> >> polybench/linear-algebra/kernels/symm, FP_TOLERANCE=1e-10 >> polybench/linear-algebra/solvers/gramschmidt, FP_TOLERANCE=1e5 > > I'm confused. Is this 1e-5 or 1e...

...deterministic. Sounds like a bug. This is with clang top of tree, on a x86_64-linux. I created https://reviews.llvm.org/D25465 with the changes that I have to the symm benchmark. > >> Furthermore, compiling this kernel at -Ofast and comparing against >> -O0 >> only passes for FP_ABSTOLERANCE=10. >> All the 10 other polybench tests that I have transformed to check FP >> are passing at FP_ABSTOLERANCE=1e-5 (and most likely they could pass >> at an even more reduced tolerance.) >> >> The symm benchmark seems to accumulate all the errors as it is a big >&gt...

On 12 October 2016 at 05:35, Sebastian Pop <sebpop.llvm at gmail.com> wrote: > polybench/linear-algebra/solvers/gramschmidt/ exposes the same problems as symm. > It does not match the reference output at -O0 -ffp-contract=off, > and it only passes all elements comparisons for FP_ABSTOLERANCE=1 for > "-Ofast" vs. "-O0 -ffp-contract=off". I think we're going about this in a completely wrong way. The current reference output is specific to fp-contract=off, and making it work for fp-contract=on makes no sense at all. For all we know, fp-contract=on generates *...

On Tue, Oct 11, 2016 at 10:39 PM, Sebastian Pop <sebpop.llvm at gmail.com> wrote: > On Tue, Oct 11, 2016 at 10:20 PM, Hal Finkel <hfinkel at anl.gov> wrote: >> ----- Original Message ----- >>> From: "Renato Golin" <renato.golin at linaro.org> >>> To: "Sebastian Pop" <sebpop.llvm at gmail.com> >>> Cc: "Hal