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| author | J"orn Rennecke <amylaar@cygnus.co.uk> | 2000-02-15 22:34:33 +0000 |
|---|---|---|
| committer | Joern Rennecke <amylaar@gcc.gnu.org> | 2000-02-15 22:34:33 +0000 |
| commit | 9f09b1f27285bb8b72ee3fa02619fc2fac845b3b (patch) | |
| tree | e647915f74630ab20a46bfbbd0f14b62bd524134 /gcc/tm.texi | |
| parent | 78de74bea93ed92acb7c78ebb9293eb6f1d08b15 (diff) | |
| download | gcc-9f09b1f27285bb8b72ee3fa02619fc2fac845b3b.tar.gz | |
Makefile.in (lcm.o): Depend on insn-attr.h.
* Makefile.in (lcm.o): Depend on insn-attr.h.
* basic-block.h (optimize_mode_switching): Declare.
* lcm.c (tm_p.h, insn-attr.h): #include.
(seginfo, bb_info): New structs.
(antic, transp, comp, delete, insert) : New file-scope static variables.
(new_seginfo, add_seginfo, make_preds_opaque, reg_dies): New functions.
(reg_becomes_live, optimize_mode_switching): Likewise.
* tm.texi: Add description of mode switching macros.
* toplev.c (rest_of_compilation): Call optimize_mode_switching.
* sh-protos.h (remove_dead_before_cse): Remove prototype.
(fldi_ok, fpscr_set_from_mem): New prototypes.
* sh.h (OPTIMIZATION_OPTION): Remove sh_flag_remove_dead_before_cse set.
(CONST_DOUBLE_OK_FOR_LETTER_P, SECONDARY_INPUT_RELOAD_CLASS):
Disable fldi for (TARGET_SH4 && ! TARGET_FMOVD).
(sh_flag_remove_dead_before_cse): Remove declaration.
(NUM_MODES_FOR_MODE_SWITCHING, OPTIMIZE_MODE_SWITCHING): New macros.
(MODE_USES_IN_EXIT_BLOCK, MODE_NEEDED, MODE_AT_ENTRY): Likewise.
(MODE_PRIORITY_TO_MODE, EMIT_MODE_SET): Likewise.
* sh.c (broken_move): Disable fldi for (TARGET_SH4 && ! TARGET_FMOVD).
(barrier_align): Allow for JUMP_INSNS containing a parallel.
(machine_dependent_reorg): Remove sh_flag_remove_dead_before_cse set.
(fldi_ok): New function.
(get_fpscr_rtx): Add fpscr_rtx as GC root.
(emit_sf_insn): Only generate fpu switches when optimize < 1.
(emit_df_insn): Likewise.
(expand_fp_branch, emit_fpscr_use, remove_dead_before_cse): Delete.
(sh_flag_remove_dead_before_cse): Delete.
(get_free_reg, fpscr_set_from_mem): New functions.
* sh.md (movdf, movsf): Remove no_new_pseudos code.
(return): Remove emit_fpscr_use / remove_dead_before_cse calls.
Co-Authored-By: Andrew MacLeod <amacleod@cygnus.com>
From-SVN: r31990
Diffstat (limited to 'gcc/tm.texi')
| -rw-r--r-- | gcc/tm.texi | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/gcc/tm.texi b/gcc/tm.texi index 14365ce0c24..fe89ee080d2 100644 --- a/gcc/tm.texi +++ b/gcc/tm.texi @@ -37,6 +37,7 @@ includes @file{tm.h} and most compiler source files include * Assembler Format:: Defining how to write insns and pseudo-ops to output. * Debugging Info:: Defining the format of debugging output. * Cross-compilation:: Handling floating point for cross-compilers. +* Mode Switching:: Insertion of mode-switching instructions. * Misc:: Everything else. @end menu @@ -7194,6 +7195,85 @@ The value is in the target machine's representation for mode @var{mode} and has the type @code{REAL_VALUE_TYPE}. @end table +@node Mode Switching +@section Mode Switching Instructions +@cindex mode switching +The following macros control mode switching optimizations: + +@table @code +@findex OPTIMIZE_MODE_SWITCHING +@item OPTIMIZE_MODE_SWITCHING (@var{entity}) +Define this macro if the port needs extra instructions inserted for mode +switching in an optimizing compilation. + +For an example, the SH4 can perform both single and double precision +floating point operations, but to perform a single precision operation, +the FPSCR PR bit has to be cleared, while for a double precision +operation, this bit has to be set. Changing the PR bit requires a general +purpose register as a scratch register, hence these FPSCR sets have to +be inserted before reload, i.e. you can't put this into instruction emitting +or MACHINE_DEPENDENT_REORG. + +You can have multiple entities that are mode-switched, and select at run time +which entities actually need it. @code{OPTIMIZE_MODE_SWITCHING} should +return non-zero for any @var{entity} that that needs mode-switching. +If you define this macro, you also have to define +@code{NUM_MODES_FOR_MODE_SWITCHING}, @code{MODE_NEEDED}, +@code{MODE_PRIORITY_TO_MODE} and @code{EMIT_MODE_SET}. +@code{MODE_AT_ENTRY} and @code{MODE_USES_IN_EXIT_BLOCK} are optional. + +@findex NUM_MODES_FOR_MODE_SWITCHING +@item NUM_MODES_FOR_MODE_SWITCHING +If you define @code{OPTIMIZE_MODE_SWITCHING}, you have to define this as +initializer for an array of integers. Each initializer element +N refers to an entity that needs mode switching, and specifies the number +of different modes that might need to be set for this entity. +The position of the initializer in the initializer - starting counting at +zero - determines the integer that is used to refer to the mode-switched +entity in question. +In macros that take mode arguments / yield a mode result, modes are +represented as numbers 0 .. N - 1. N is used to specify that no mode +switch is needed / supplied. + +@findex MODE_USES_IN_EXIT_BLOCK +@item MODE_USES_IN_EXIT_BLOCK +If this macro is defined, it is called for each exit block when mode switching +optimization is performed. Its return value should be the pattern of an insn, +or a sequence of insns. It is emitted before the return insn / use insns at +the end of the exit block. + +This is done before insns are examined for their need of any mode switching. + +@findex MODE_NEEDED +@item MODE_NEEDED (@var{entity}, @var{insn}) +@var{entity} is an integer specifying a mode-switched entity. If +@code{OPTIMIZE_MODE_SWITCHING} is defined, you must define this macro to +return an integer value not larger than the corresponding element in +NUM_MODES_FOR_MODE_SWITCHING, to denote the mode that @var{entity} must +be switched into prior to the execution of INSN. + +@findex MODE_AT_ENTRY +@item MODE_AT_ENTRY (@var{entity}) +If this macro is defined, it is evaluated for every @var{entity} that needs +mode switching. It should evaluate to an integer, which is a mode that +@var{entity} is assumed to be switched to at function entry. + +@findex MODE_PRIORITY_TO_MODE +@item MODE_PRIORITY_TO_MODE (@var{entity}, @var{n}) +This macro specifies the order in which modes for ENTITY are processed. +0 is the highest priority, NUM_MODES_FOR_MODE_SWITCHING[ENTITY] - 1 the +lowest. The value of the macro should be an integer designating a mode +for ENTITY. For any fixed @var{entity}, @code{mode_priority_to_mode} +(@var{entity}, @var{n}) shall be a bijection in 0 .. +@code{num_modes_for_mode_switching}[@var{entity}] - 1 . + +@findex EMIT_MODE_SET +@item EMIT_MODE_SET (@var{entity}, @var{mode}, @var{hard_regs_live}) +Generate one or more insns to set @var{entity} to @var{mode}. +@var{hard_reg_live} is the set of hard registers live at the point where +the insn(s) are to be inserted. +@end table + @node Misc @section Miscellaneous Parameters @cindex parameters, miscellaneous |