Enable constant propagation for more math functions

Thu Aug 27 11:14:24 PDT 2015

This commit led to test suite failures (see e.g. <
http://lab.llvm.org:8011/builders/clang-x86_64-debian-fast/builds/30501>),
so I reverted it.

Locally, everything is fine if I run "make check". Do you have pointers for
debugging this?

-erik

On Thu, Aug 27, 2015 at 12:41 PM, Erik Schnetter <schnetter at gmail.com>
wrote:

> Committed as 246158.
>
> -erik
>
> On Wed, Aug 26, 2015 at 1:51 PM, Vedant Kumar <vsk at apple.com> wrote:
>
>> LGTM, this is ready to land.
>>
>> It turns out that we _can_ combine these tests. I'll take care of it in a
>> followup patch since existing tests need to be changed.
>>
>> > >> +define float @test_atan2f() nounwind uwtable ssp {
>> > >> +entry:
>> > >> +; CHECK-LABEL: @test_atan2f(
>> > >> +; CHECK-NOT: call
>> > >> +  %0 = call float @atan2f(float 3.000000e+00, float 4.000000e+00)
>> > >> +  ret float %0
>> > >> +}
>> > >>
>> > >> +; Shouldn't fold because of -fno-builtin
>> > >> +define float @atan2f_() nounwind uwtable ssp {
>> > >> +; FNOBUILTIN-LABEL: @atan2f_(
>> > >> +; FNOBUILTIN: %1 = call float @atan2f(float 3.000000e+00, float
>> 4.000000e+00)
>> > >> +  %1 = call float @atan2f(float 3.000000e+00, float 4.000000e+00)
>> > >> +  ret float %1
>> > >> +}
>> >
>> > I've noticed many pairs of test functions like the one above. Can this
>> pair be combined into one function? E.g:
>> >
>> > >> +define float @atan2f_() nounwind uwtable ssp {
>> > >> +; CHECK-LABEL: @_atan2f(
>> > >> +; FNOBUILTIN-LABEL: @atan2f_(
>> > >> +; CHECK-NOT: call
>> > >> +; FNOBUILTIN: %1 = call float @atan2f(float 3.000000e+00, float
>> 4.000000e+00)
>> > >> +  %1 = call float @atan2f(float 3.000000e+00, float 4.000000e+00)
>> > >> +  ret float %1
>> > >> +}
>> >
>> > I don't know, I'm not too familiar with the test system. These are two
>> different tests: in one, the call should be eliminated (constant-folded),
>> in the other case, it should not. Do you have a pointer to documentation or
>> other examples that cover this detail?
>>
>> Your ">> +; CHECK-NOT: call" lines check that there is "NOT" a "call",
>> i.e the call is folded away. When "-fno-builtin" is passed to the compiler
>> however, we want the call preserved. FileCheck lets you specify different
>> check prefixes for different usage scenarios.
>>
>> Googling "llvm-lit" or "llvm FileCheck" should turn something up.
>>
>> thanks!
>> vedant
>>
>> >
>> > If so, it would be nice to reduce the test case size. Apart from that,
>> please run clang-format -style=llvm on your changes. Everything else looks
>> good.
>> >
>> > I attach the updated (re-formatted) patch.
>> >
>> > -erik
>> >
>> > vedant
>> >
>> > On Aug 25, 2015, at 1:14 PM, Erik Schnetter via llvm-commits <
>> llvm-commits at lists.llvm.org> wrote:
>> >
>> > > It seems that constant propagation for single precision math
>> functions (such as tanf) is already working, but was not enabled. This
>> patch enables these for many single-precision functions, and adds
>> respective test cases.
>> > >
>> > > List of newly handled functions: acosf asinf atanf atan2f ceilf coshf
>> expf exp2f fabsf floorf fmodf logf log10f powf sinhf tanf tanhf
>> > >
>> > > -erik
>> > >
>> > > --
>> > > Erik Schnetter <schnetter at gmail.com>
>> http://www.perimeterinstitute.ca/personal/eschnetter/
>> > > <constprop.diff>_______________________________________________
>> > > llvm-commits mailing list
>> > > llvm-commits at lists.llvm.org
>> > >
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>> >
>> >
>> >
>> >
>> > --
>> > Erik Schnetter <schnetter at gmail.com>
>> http://www.perimeterinstitute.ca/personal/eschnetter/
>> > <constprop.diff>_______________________________________________
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>> >
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>>
>>
>
>
> --
> Erik Schnetter <schnetter at gmail.com>
> http://www.perimeterinstitute.ca/personal/eschnetter/
>

-- 
Erik Schnetter <schnetter at gmail.com>
http://www.perimeterinstitute.ca/personal/eschnetter/
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