On Fri, Dec 13, 2024 at 6:31 AM Christophe Lyon
<[email protected]> wrote:
>
> On Tue, 10 Dec 2024 at 13:14, Richard Earnshaw (lists)
> <[email protected]> wrote:
> >
> > On 09/12/2024 21:11, Christophe Lyon wrote:
> > > In this PR, we have to handle a case where MVE predicates are supplied
> > > as a const_int, where individual predicates have illegal boolean
> > > values (such as 0xc for a 4-bit boolean predicate). To avoid the ICE,
> > > fix the constant (any non-zero value is converted to all 1s) and emit
> > > a warning.
> > >
> > > On MVE, V8BI and V4BI multi-bit masks are interpreted byte-by-byte at
> > > instruction level, but end-users should describe lanes rather than
> > > bytes (so all bytes of a true-predicated lane should be '1'), see the
> > > section on MVE intrinsics in the Arm ACLE specification.
> > >
> > > Since force_lowpart_subreg cannot handle const_int (because they have
> > > VOID mode),
> > > use gen_lowpart on them, force_lowpart_subreg otherwise.
> > >
> > > 2024-11-20 Christophe Lyon <[email protected]>
> > > Jakub Jelinek <[email protected]>
> > >
> > > PR target/114801
> > > gcc/
> > > * config/arm/arm-mve-builtins.cc
> > > (function_expander::add_input_operand): Handle CONST_INT
> > > predicates.
> > >
> > > gcc/testsuite/
> > > * gcc.target/arm/mve/pr108443.c: Update predicate constant.
> > > * gcc.target/arm/mve/pr108443-run.c: Likewise.
> > > * gcc.target/arm/mve/pr114801.c: New test.
> >
> > Thanks, that looks much better. OK, assuming no regressions.
> >
>
> Indeed, thanks for your suggestions.
>
> OK to backport to gcc-14 after a while?
Except force_lowpart_subreg does not exist on the 14 branch.
Did you test it there before pushing it?
Thanks,
Andrew Pinski
>
> Thanks,
>
> Christophe
>
>
> > R.
> >
> > > ---
> > > gcc/config/arm/arm-mve-builtins.cc | 32 ++++++++++++++-
> > > .../gcc.target/arm/mve/pr108443-run.c | 2 +-
> > > gcc/testsuite/gcc.target/arm/mve/pr108443.c | 4 +-
> > > gcc/testsuite/gcc.target/arm/mve/pr114801.c | 39 +++++++++++++++++++
> > > 4 files changed, 73 insertions(+), 4 deletions(-)
> > > create mode 100644 gcc/testsuite/gcc.target/arm/mve/pr114801.c
> > >
> > > diff --git a/gcc/config/arm/arm-mve-builtins.cc
> > > b/gcc/config/arm/arm-mve-builtins.cc
> > > index 8570e18fd96..3c3d30bd0de 100644
> > > --- a/gcc/config/arm/arm-mve-builtins.cc
> > > +++ b/gcc/config/arm/arm-mve-builtins.cc
> > > @@ -2358,7 +2358,37 @@ function_expander::add_input_operand (insn_code
> > > icode, rtx x)
> > > mode = GET_MODE (x);
> > > }
> > > else if (VALID_MVE_PRED_MODE (mode))
> > > - x = gen_lowpart (mode, x);
> > > + {
> > > + if (CONST_INT_P (x))
> > > + {
> > > + if (mode == V8BImode || mode == V4BImode)
> > > + {
> > > + /* In V8BI or V4BI each element has 2 or 4 bits, if those bits
> > > + aren't all the same, gen_lowpart might ICE. Canonicalize
> > > all
> > > + the 2 or 4 bits to all ones if any of them is non-zero.
> > > V8BI
> > > + and V4BI multi-bit masks are interpreted byte-by-byte at
> > > + instruction level, but such constants should describe
> > > lanes,
> > > + rather than bytes. See the section on MVE intrinsics in
> > > the
> > > + Arm ACLE specification. */
> > > + unsigned HOST_WIDE_INT xi = UINTVAL (x);
> > > + xi |= ((xi & 0x5555) << 1) | ((xi & 0xaaaa) >> 1);
> > > + if (mode == V4BImode)
> > > + xi |= ((xi & 0x3333) << 2) | ((xi & 0xcccc) >> 2);
> > > + if (xi != UINTVAL (x))
> > > + warning_at (location, 0, "constant predicate argument %d"
> > > + " (%wx) does not map to %d lane numbers,"
> > > + " converted to %wx",
> > > + opno, UINTVAL (x) & 0xffff,
> > > + mode == V8BImode ? 8 : 4,
> > > + xi & 0xffff);
> > > +
> > > + x = gen_int_mode (xi, HImode);
> > > + }
> > > + x = gen_lowpart (mode, x);
> > > + }
> > > + else
> > > + x = force_lowpart_subreg (mode, x, GET_MODE (x));
> > > + }
> > >
> > > m_ops.safe_grow (m_ops.length () + 1, true);
> > > create_input_operand (&m_ops.last (), x, mode);
> > > diff --git a/gcc/testsuite/gcc.target/arm/mve/pr108443-run.c
> > > b/gcc/testsuite/gcc.target/arm/mve/pr108443-run.c
> > > index cb4b45bd305..b894f019b8b 100644
> > > --- a/gcc/testsuite/gcc.target/arm/mve/pr108443-run.c
> > > +++ b/gcc/testsuite/gcc.target/arm/mve/pr108443-run.c
> > > @@ -16,7 +16,7 @@ __attribute__ ((noipa)) partial_write (uint32_t *a,
> > > uint32x4_t v, unsigned short
> > >
> > > int main (void)
> > > {
> > > - unsigned short p = 0x00CC;
> > > + unsigned short p = 0x00FF;
> > > uint32_t a[] = {0, 0, 0, 0};
> > > uint32_t b[] = {0, 0, 0, 0};
> > > uint32x4_t v = vdupq_n_u32 (0xFFFFFFFFU);
> > > diff --git a/gcc/testsuite/gcc.target/arm/mve/pr108443.c
> > > b/gcc/testsuite/gcc.target/arm/mve/pr108443.c
> > > index c5fbfa4a1bb..0c0e2dd6eb8 100644
> > > --- a/gcc/testsuite/gcc.target/arm/mve/pr108443.c
> > > +++ b/gcc/testsuite/gcc.target/arm/mve/pr108443.c
> > > @@ -7,8 +7,8 @@
> > > void
> > > __attribute__ ((noipa)) partial_write_cst (uint32_t *a, uint32x4_t v)
> > > {
> > > - vstrwq_p_u32 (a, v, 0x00CC);
> > > + vstrwq_p_u32 (a, v, 0x00FF);
> > > }
> > >
> > > -/* { dg-final { scan-assembler {mov\tr[0-9]+, #204} } } */
> > > +/* { dg-final { scan-assembler {mov\tr[0-9]+, #255} } } */
> > >
> > > diff --git a/gcc/testsuite/gcc.target/arm/mve/pr114801.c
> > > b/gcc/testsuite/gcc.target/arm/mve/pr114801.c
> > > new file mode 100644
> > > index 00000000000..ab3130fd4ce
> > > --- /dev/null
> > > +++ b/gcc/testsuite/gcc.target/arm/mve/pr114801.c
> > > @@ -0,0 +1,39 @@
> > > +/* { dg-do compile } */
> > > +/* { dg-require-effective-target arm_v8_1m_mve_ok } */
> > > +/* { dg-options "-O2" } */
> > > +/* { dg-add-options arm_v8_1m_mve } */
> > > +/* { dg-final { check-function-bodies "**" "" "" } } */
> > > +
> > > +#include <arm_mve.h>
> > > +
> > > +/*
> > > +** test_32:
> > > +**...
> > > +** mov r[0-9]+, #65295 @ movhi
> > > +**...
> > > +*/
> > > +uint32x4_t test_32() {
> > > + /* V4BI predicate converted to 0xff0f. */
> > > + return vdupq_m_n_u32(vdupq_n_u32(0xffffffff), 0, 0x4f02); /* {
> > > dg-warning {constant predicate argument 3 \(0x4f02\) does not map to 4
> > > lane numbers, converted to 0xff0f} } */
> > > +}
> > > +
> > > +/*
> > > +** test_16:
> > > +**...
> > > +** mov r[0-9]+, #12339 @ movhi
> > > +**...
> > > +*/
> > > +uint16x8_t test_16() {
> > > + /* V8BI predicate converted to 0x3033. */
> > > + return vdupq_m_n_u16(vdupq_n_u16(0xffff), 0, 0x3021); /* { dg-warning
> > > {constant predicate argument 3 \(0x3021\) does not map to 8 lane numbers,
> > > converted to 0x3033} } */
> > > +}
> > > +
> > > +/*
> > > +** test_8:
> > > +**...
> > > +** mov r[0-9]+, #23055 @ movhi
> > > +**...
> > > +*/
> > > +uint8x16_t test_8() {
> > > + return vdupq_m_n_u8(vdupq_n_u8(0xff), 0, 0x5a0f);
> > > +}
> >
