Enable constant propagation for more math functions

Thu Aug 27 11:38:48 PDT 2015

check-all runs fine on my machine too. From the logs, I see:

>> <stdin>:372:7: error: CHECK-NOT: string occurred!
>>  %1 = call double @acos(double 3.000000e+00)
>>       ^
>> /home/llvmbb/llvm-build-dir/clang-x86_64-debian-fast/llvm.src/test/Transforms/ConstProp/calls.ll:421:14: note: CHECK-NOT: pattern specified here
>> ; CHECK-NOT: call

However, line 421 of calls.ll tests is:

    "%0 = call float @tanhf(float 3.000000e+00)",

and the output string FileCheck matches against is:

    "%1 = call double @acos(double 3.000000e+00)" (from line 430).

So I suspect that the code is fine but the test case is flaky. I will keep looking at this, but I thought I'd shoot this email back at you now in case it helps :).

vedant

> On Aug 27, 2015, at 11:14 AM, Erik Schnetter <schnetter at gmail.com> wrote:
> 
> 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>_______________________________________________
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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/
> 
> 
> 
> -- 
> Erik Schnetter <schnetter at gmail.com> http://www.perimeterinstitute.ca/personal/eschnetter/