On Wed, Oct 23, 2024 at 8:38 PM Jeff Law <jeffreya...@gmail.com> wrote: > > > > On 10/20/24 3:18 PM, Andrew Pinski wrote: > > The gimple (and generic) levels have this optmization since > > r12-2041-g7d6979197274a662da7bdc5. > > It seems like a good idea to add a similar one to rtl just in case it is > > not caught at the > > gimple level. > > > > Note the loop case in csel-neg-1.c is not handled at the gimple level (even > > with phiopt turned back on), > > this is because of casts to avoid signed integer overflow; a patch to fix > > this at the gimple level will be > > submitted seperately. > > > > Build and tested for aarch64-linux-gnu. > > > > PR rtl-optimization/58195 > > > > gcc/ChangeLog: > > > > * simplify-rtx.cc (simplify_context::simplify_ternary_operation): > > Handle > > `a != 0 ? -a : 0` and `a == 0 ? 0 : -a`. > > > > gcc/testsuite/ChangeLog: > > > > * gcc.target/aarch64/csel-neg-1.c: New test. > > > > Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com> > > --- > > gcc/simplify-rtx.cc | 22 +++++++++++++ > > gcc/testsuite/gcc.target/aarch64/csel-neg-1.c | 31 +++++++++++++++++++ > > 2 files changed, 53 insertions(+) > > create mode 100644 gcc/testsuite/gcc.target/aarch64/csel-neg-1.c > > > > diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc > > index 4d024ec523b..93a1b707425 100644 > > --- a/gcc/simplify-rtx.cc > > +++ b/gcc/simplify-rtx.cc > > @@ -6909,6 +6909,28 @@ simplify_context::simplify_ternary_operation > > (rtx_code code, machine_mode mode, > > && rtx_equal_p (XEXP (op0, 1), op1)))) > > return op2; > > > > + /* Convert a != 0 ? -a : 0 into "-a". */ > > + if (GET_CODE (op0) == NE > > + && ! side_effects_p (op0) > > + && ! HONOR_NANS (mode) > > + && ! HONOR_SIGNED_ZEROS (mode) > > + && XEXP (op0, 1) == const0_rtx > > + && op2 == const0_rtx > Shouldn't we be using CONST0_RTX (mode) rather than referencing > const0_rtx directly?
yes it should. This is what I pushed after a testing for aarch64 again. Also I added a new testcase for the float case which is now works with the above change. Thanks, Andrew > > OK with that change in both clauses. > > Jeff
v2-0001-simplify-rtx-Handle-a-0-a-0-PR58195.patch
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