Current code to handle -mslow-flash-data in machine description files
suffers from a number of issues which this patch fixes:
1) The insn_and_split in vfp.md to load a generic floating-point
constant via GPR first and move it to VFP register are guarded by
!reload_completed which is forbidden explicitely in the GCC internals
documentation section 17.2 point 3;
2) A number of testcase in the testsuite ICEs under -mslow-flash-data
when targeting the hardfloat ABI [1];
3) Instructions performing load from literal pool are not disabled.
These problems are addressed by 2 separate actions:
1) Making the splitters take a clobber and changing the expanders
accordingly to generate a mov with clobber in cases where a literal
pool would be used. The splitter can thus be enabled after reload since
it does not call gen_reg_rtx anymore;
2) Adding new predicates and constraints to disable literal pool loads
in existing instructions when -mslow-flash-data is in effect.
The patch also rework the splitter for DFmode slightly to generate an
intermediate DI load instead of 2 intermediate SI loads, thus relying on
the existing DI splitters instead of redoing their job. At last, the
patch adds some missing arm_fp_ok effective target to some of the
slow-flash-data testcases.
[1]
c-c++-common/Wunused-var-3.c
gcc.c-torture/compile/pr72771.c
gcc.c-torture/compile/vector-5.c
gcc.c-torture/compile/vector-6.c
gcc.c-torture/execute/20030914-1.c
gcc.c-torture/execute/20050316-1.c
gcc.c-torture/execute/pr59643.c
gcc.dg/builtin-tgmath-1.c
gcc.dg/debug/pr55730.c
gcc.dg/graphite/interchange-7.c
gcc.dg/pr56890-2.c
gcc.dg/pr68474.c
gcc.dg/pr80286.c
gcc.dg/torture/pr35227.c
gcc.dg/torture/pr65077.c
gcc.dg/torture/pr86363.c
g++.dg/torture/pr81112.C
g++.dg/torture/pr82985.C
g++.dg/warn/Wunused-var-7.C
and a lot more in libstdc++ in special_functions/*_comp_ellint_* and
special_functions/*_ellint_* directories.
2018-12-14 Thomas Preud'homme <thomas.preudhomme@arm.com>
gcc/
* config/arm/arm.md (arm_movdi): Split if -mslow-flash-data and
source is a constant that would be loaded by literal pool.
(movsf expander): Generate a no_literal_pool_sf_immediate insn if
-mslow-flash-data is present, targeting hardfloat ABI and source is a
float constant that cannot be loaded via vmov.
(movdf expander): Likewise but generate a no_literal_pool_df_immediate
insn.
(arm_movsf_soft_insn): Split if -mslow-flash-data and source is a
float constant that would be loaded by literal pool.
(softfloat constant movsf splitter): Splitter for the above case.
(movdf_soft_insn): Split if -mslow-flash-data and source is a float
constant that would be loaded by literal pool.
(softfloat constant movdf splitter): Splitter for the above case.
* config/arm/constraints.md (Pz): Document existing constraint.
(Ha): Define constraint.
(Tu): Likewise.
* config/arm/predicates.md (hard_sf_operand): New predicate.
(hard_df_operand): Likewise.
* config/arm/thumb2.md (thumb2_movsi_insn): Split if
-mslow-flash-data and constant would be loaded by literal pool.
* constant/arm/vfp.md (thumb2_movsi_vfp): Likewise and disable constant
load in VFP register.
(movdi_vfp): Likewise.
(thumb2_movsf_vfp): Use hard_sf_operand as predicate for source to
prevent match for a constant load if -mslow-flash-data and constant
cannot be loaded via vmov. Adapt constraint accordingly by
using Ha instead of E for generic floating-point constant load.
(thumb2_movdf_vfp): Likewise using hard_df_operand predicate instead.
(no_literal_pool_df_immediate): Add a clobber to use as the
intermediate general purpose register and also enable it after reload
but disable it constant is a valid FP constant. Add constraints and
generate a DI intermediate load rather than 2 SI loads.
(no_literal_pool_sf_immediate): Add a clobber to use as the
intermediate general purpose register and also enable it after
reload.
2018-11-14 Thomas Preud'homme <thomas.preudhomme@arm.com>
gcc/testsuite/
* gcc.target/arm/thumb2-slow-flash-data-2.c: Require arm_fp_ok
effective target.
* gcc.target/arm/thumb2-slow-flash-data-3.c: Likewise.
* gcc.target/arm/thumb2-slow-flash-data-4.c: Likewise.
* gcc.target/arm/thumb2-slow-flash-data-5.c: Likewise.
From-SVN: r267141
