Enable constant propagation for more math functions

[Erik Schnetter via llvm-commits]

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


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