[PATCH] Fix SFmode subreg of DImode and TImode
This patch fixes the breakage in the PowerPC due to a recent change in SUBREG
behavior. While it is arguable that the patch that caused the breakage should
be reverted, this patch should be a bandage to prevent these changes from
happening again.
I first noticed it in building the Spec 2017 wrf_r and blender_r
benchmarks. Once I applied this patch, I also noticed several of the
tests now pass.
The core of the problem is we need to treat SUBREG's of SFmode and SImode
specially on the PowerPC. This is due to the fact that SFmode values that are
in the vector and floating point registers are represented as DFmode. When we
want to do a direct move between the GPR registers and the vector registers, we
have to convert the value from the DFmode representation to/from the SFmode
representation.
By doing this special processing instead of doing the transfer via store and
load, we were able to speed up the math library which at times want to use the
SFmode values in a union, and do logical operations on it (to test exponent
ranges, etc.) and then move it over to use as a floating point value.
I did a bootstrap build on a little endian power9 system with and without the
patch applied. There was no regression in the tests. I'm doing a build on a
big endian power8 system, but it hasn't finished yet as I sent this email. I
will check on the big endian progress tomorrow morning.
The following tests now pass once again with the test.
C tests:
========
gcc.c-torture/compile/20071102-1.c
gcc.c-torture/compile/pr55921.c
gcc.c-torture/compile/pr85945.c
gcc.c-torture/execute/complex-3.c
gcc.dg/atomic/c11-atomic-exec-1.c
gcc.dg/atomic/c11-atomic-exec-2.c
gcc.dg/atomic/c11-atomic-exec-4.c
gcc.dg/atomic/c11-atomic-exec-5.c
gcc.dg/c11-atomic-2.c
gcc.dg/pr42475.c
gcc.dg/pr47201.c
gcc.dg/pr48335-1.c
gcc.dg/torture/pr67741.c
gcc.dg/tree-ssa/ssa-dom-thread-10.c
gcc.dg/tsan/pr88030.c
gcc.dg/ubsan/float-cast-overflow-atomic.c
gcc.dg/vect/no-tree-sra-bb-slp-pr50730.c
C++ tests:
==========
g++.dg/opt/alias1.C
g++.dg/template/koenig6.C
g++.dg/torture/pr40924.C
tmpdir-g++.dg-struct-layout-1/t001
Fortran tests:
==============
gfortran.dg/array_constructor_type_22.f03
gfortran.dg/array_function_6.f90
gfortran.dg/derived_comp_array_ref_7.f90
gfortran.dg/elemental_scalar_args_1.f90
gfortran.dg/elemental_subroutine_1.f90
gfortran.dg/inline_matmul_5.f90
gfortran.dg/inline_matmul_8.f90
gfortran.dg/inline_matmul_9.f90
gfortran.dg/matmul_bounds_6.f90
gfortran.dg/operator_1.f90
gfortran.dg/past_eor.f90
gfortran.dg/pr101121.f
gfortran.dg/pr91552.f90
gfortran.dg/spread_shape_1.f90
gfortran.dg/typebound_operator_3.f03
gfortran.dg/value_1.f90
gfortran.fortran-torture/execute/entry_4.f90
gfortran.fortran-torture/execute/intrinsic_dotprod.f90
gfortran.fortran-torture/execute/intrinsic_matmul.f90
Can I check this fix into the master branch?
2021-09-06 Michael Meissner <meiss...@linux.ibm.com>
gcc/
* config/rs6000/rs6000.c (rs6000_emit_move_si_sf_subreg): Deal
with SUBREGs of TImode and DImode.
---
gcc/config/rs6000/rs6000.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index b9ebd56c993..7bbf29a3e1c 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -10942,6 +10942,16 @@ rs6000_emit_move_si_sf_subreg (rtx dest, rtx source,
machine_mode mode)
return true;
}
+ /* In case we are given a SUBREG for a larger type, reduce it to
+ SImode. */
+ if (mode == SFmode && GET_MODE_SIZE (inner_mode) > 4)
+ {
+ rtx tmp = gen_reg_rtx (SImode);
+ emit_move_insn (tmp, gen_lowpart (SImode, source));
+ emit_insn (gen_movsf_from_si (dest, tmp));
+ return true;
+ }
+
if (mode == SFmode && inner_mode == SImode)
{
emit_insn (gen_movsf_from_si (dest, inner_source));
--
2.31.1
--
Michael Meissner, IBM
IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA
email: meiss...@linux.ibm.com, phone: +1 (978) 899-4797
