On Mon, Jan 29, 2024 at 5:00 PM Richard Sandiford
<richard.sandif...@arm.com> wrote:
>
> Tamar Christina <tamar.christ...@arm.com> writes:
> > Hi All,
> >
> > Recently something in the midend had started inverting the branches by
> > inverting
> > the condition and the branches.
> >
> > While this is fine, it makes it hard to actually test. In RTL I disable
> > scheduling and BB reordering to prevent this. But in GIMPLE there seems to
> > be
> > nothing I can do. __builtin_expect seems to have no impact on the change
> > since
> > I suspect this is happening during expand where conditions can be flipped
> > regardless of probability during compare_and_branch.
> >
> > Since the mid-end has plenty of correctness tests, this weakens the backend
> > tests to just check that a correct looking sequence is emitted.
> >
> > Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.
> >
> > Ok for master?
> >
> > Thanks,
> > Tamar
> >
> > gcc/testsuite/ChangeLog:
> >
> > PR testsuite/113502
> > * gcc.target/aarch64/sve/vect-early-break-cbranch.c: Ignore exact
> > branch.
> > * gcc.target/aarch64/vect-early-break-cbranch.c: Likewise.
>
> OK I guess, since I agree that the "polarity" of the branch isn't really the
> thing that we're trying to test. But the fact that even __builtin_expect
> doesn't work seems like a bug. Do we have a PR for that? Might be worth
> filing one (for GCC 15+) if we don't.
But that only should affect which edge is fallthru, not the "polarity"
of the branch, no?
> Thanks,
> Richard
>
> >
> > --- inline copy of patch --
> > diff --git
> > a/gcc/testsuite/gcc.target/aarch64/sve/vect-early-break-cbranch.c
> > b/gcc/testsuite/gcc.target/aarch64/sve/vect-early-break-cbranch.c
> > index
> > d15053553f94e7dce3540e21f0c1f0d39ea4f289..d7cef1105410be04ed67d1d3b800746267f205a8
> > 100644
> > --- a/gcc/testsuite/gcc.target/aarch64/sve/vect-early-break-cbranch.c
> > +++ b/gcc/testsuite/gcc.target/aarch64/sve/vect-early-break-cbranch.c
> > @@ -9,7 +9,7 @@ int b[N] = {0};
> > ** ...
> > ** cmpgt p[0-9]+.s, p[0-9]+/z, z[0-9]+.s, #0
> > ** ptest p[0-9]+, p[0-9]+.b
> > -** b.any \.L[0-9]+
> > +** b.(any|none) \.L[0-9]+
> > ** ...
> > */
> > void f1 ()
> > @@ -26,7 +26,7 @@ void f1 ()
> > ** ...
> > ** cmpge p[0-9]+.s, p[0-9]+/z, z[0-9]+.s, #0
> > ** ptest p[0-9]+, p[0-9]+.b
> > -** b.any \.L[0-9]+
> > +** b.(any|none) \.L[0-9]+
> > ** ...
> > */
> > void f2 ()
> > @@ -43,7 +43,7 @@ void f2 ()
> > ** ...
> > ** cmpeq p[0-9]+.s, p[0-9]+/z, z[0-9]+.s, #0
> > ** ptest p[0-9]+, p[0-9]+.b
> > -** b.any \.L[0-9]+
> > +** b.(any|none) \.L[0-9]+
> > ** ...
> > */
> > void f3 ()
> > @@ -60,7 +60,7 @@ void f3 ()
> > ** ...
> > ** cmpne p[0-9]+.s, p[0-9]+/z, z[0-9]+.s, #0
> > ** ptest p[0-9]+, p[0-9]+.b
> > -** b.any \.L[0-9]+
> > +** b.(any|none) \.L[0-9]+
> > ** ...
> > */
> > void f4 ()
> > @@ -77,7 +77,7 @@ void f4 ()
> > ** ...
> > ** cmplt p[0-9]+.s, p7/z, z[0-9]+.s, #0
> > ** ptest p[0-9]+, p[0-9]+.b
> > -** b.any .L[0-9]+
> > +** b.(any|none) .L[0-9]+
> > ** ...
> > */
> > void f5 ()
> > @@ -94,7 +94,7 @@ void f5 ()
> > ** ...
> > ** cmple p[0-9]+.s, p[0-9]+/z, z[0-9]+.s, #0
> > ** ptest p[0-9]+, p[0-9]+.b
> > -** b.any \.L[0-9]+
> > +** b.(any|none) \.L[0-9]+
> > ** ...
> > */
> > void f6 ()
> > diff --git a/gcc/testsuite/gcc.target/aarch64/vect-early-break-cbranch.c
> > b/gcc/testsuite/gcc.target/aarch64/vect-early-break-cbranch.c
> > index
> > a5e7b94827dd70240d754a834f1d11750a9c27a9..673b781eb6d092f6311409797b20a971f4fae247
> > 100644
> > --- a/gcc/testsuite/gcc.target/aarch64/vect-early-break-cbranch.c
> > +++ b/gcc/testsuite/gcc.target/aarch64/vect-early-break-cbranch.c
> > @@ -15,7 +15,7 @@ int b[N] = {0};
> > ** cmgt v[0-9]+.4s, v[0-9]+.4s, #0
> > ** umaxp v[0-9]+.4s, v[0-9]+.4s, v[0-9]+.4s
> > ** fmov x[0-9]+, d[0-9]+
> > -** cbnz x[0-9]+, \.L[0-9]+
> > +** cbn?z x[0-9]+, \.L[0-9]+
> > ** ...
> > */
> > void f1 ()
> > @@ -34,7 +34,7 @@ void f1 ()
> > ** cmge v[0-9]+.4s, v[0-9]+.4s, #0
> > ** umaxp v[0-9]+.4s, v[0-9]+.4s, v[0-9]+.4s
> > ** fmov x[0-9]+, d[0-9]+
> > -** cbnz x[0-9]+, \.L[0-9]+
> > +** cbn?z x[0-9]+, \.L[0-9]+
> > ** ...
> > */
> > void f2 ()
> > @@ -53,7 +53,7 @@ void f2 ()
> > ** cmeq v[0-9]+.4s, v[0-9]+.4s, #0
> > ** umaxp v[0-9]+.4s, v[0-9]+.4s, v[0-9]+.4s
> > ** fmov x[0-9]+, d[0-9]+
> > -** cbnz x[0-9]+, \.L[0-9]+
> > +** cbn?z x[0-9]+, \.L[0-9]+
> > ** ...
> > */
> > void f3 ()
> > @@ -72,7 +72,7 @@ void f3 ()
> > ** cmtst v[0-9]+.4s, v[0-9]+.4s, v[0-9]+.4s
> > ** umaxp v[0-9]+.4s, v[0-9]+.4s, v[0-9]+.4s
> > ** fmov x[0-9]+, d[0-9]+
> > -** cbnz x[0-9]+, \.L[0-9]+
> > +** cbn?z x[0-9]+, \.L[0-9]+
> > ** ...
> > */
> > void f4 ()
> > @@ -91,7 +91,7 @@ void f4 ()
> > ** cmlt v[0-9]+.4s, v[0-9]+.4s, #0
> > ** umaxp v[0-9]+.4s, v[0-9]+.4s, v[0-9]+.4s
> > ** fmov x[0-9]+, d[0-9]+
> > -** cbnz x[0-9]+, \.L[0-9]+
> > +** cbn?z x[0-9]+, \.L[0-9]+
> > ** ...
> > */
> > void f5 ()
> > @@ -110,7 +110,7 @@ void f5 ()
> > ** cmle v[0-9]+.4s, v[0-9]+.4s, #0
> > ** umaxp v[0-9]+.4s, v[0-9]+.4s, v[0-9]+.4s
> > ** fmov x[0-9]+, d[0-9]+
> > -** cbnz x[0-9]+, \.L[0-9]+
> > +** cbn?z x[0-9]+, \.L[0-9]+
> > ** ...
> > */
> > void f6 ()
