compare-elim.c File Reference

Data Structures
struct	comparison_use
struct	comparison

Typedefs
typedef struct comparison *	comparison_struct_p

Functions
static rtx	conforming_compare ()
static bool	arithmetic_flags_clobber_p ()
static void	find_flags_uses_in_insn ()
static void	find_comparisons_in_bb (struct dom_walk_data *data, basic_block bb)
static void	find_comparisons ()
static rtx	maybe_select_cc_mode (struct comparison *cmp, rtx a, rtx b)
static bool	try_eliminate_compare ()
static unsigned int	execute_compare_elim_after_reload ()
static bool	gate_compare_elim_after_reload ()
rtl_opt_pass *	make_pass_compare_elim_after_reload ()

Variables
static vec< comparison_struct_p >	all_compares

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Typedef Documentation

typedef struct comparison* comparison_struct_p

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Function Documentation

static bool arithmetic_flags_clobber_p ( )

static

Look for a pattern of the "correct" form for an insn with a flags clobber
   for which we may be able to eliminate a compare later.  We're not looking
   to validate any inputs at this time, merely see that the basic shape is
   correct.  The term "arithmetic" may be somewhat misleading...   

References extract_asm_operands(), SET, and targetm.

Referenced by find_comparisons_in_bb().

static rtx conforming_compare ( )

static

Look for a "conforming" comparison, as defined above.  If valid, return
   the rtx for the COMPARE itself.   

References targetm.

Referenced by find_comparisons_in_bb().

static unsigned int execute_compare_elim_after_reload ( )

static

Main entry point to the pass.   

References df_analyze(), find_comparisons(), and try_eliminate_compare().

static void find_comparisons ( )

static

Find all comparisons in the function.   

References dom_walk_data::before_dom_children, calculate_dominance_info(), CDI_DOMINATORS, clear_aux_for_blocks(), find_comparisons_in_bb(), fini_walk_dominator_tree(), free_dominance_info(), init_walk_dominator_tree(), memset(), and walk_dominator_tree().

Referenced by execute_compare_elim_after_reload().

static void find_comparisons_in_bb ( struct dom_walk_data *  data, basic_block  bb  )

static

Identify comparison instructions within BB.  If the flags from the last
   compare in the BB is live at the end of the block, install the compare
   in BB->AUX.  Called via walk_dominators_tree.   

References arithmetic_flags_clobber_p(), basic_block_def::aux, bitmap_bit_p(), bitmap_clear(), conforming_compare(), delete_insn(), edge_def::dest, df_get_live_in(), df_get_live_out(), df_simulate_find_defs(), find_flags_uses_in_insn(), gen_rtx_REG(), comparison::in_a, comparison::in_b, comparison::inputs_valid, comparison::insn, comparison::missing_uses, new_mode(), comparison::orig_mode, comparison::prev_clobber, rtx_equal_p(), single_pred(), single_pred_p(), basic_block_def::succs, targetm, and validate_change().

Referenced by find_comparisons().

static void find_flags_uses_in_insn ( )

static

Look for uses of FLAGS in INSN.  If we find one we can analyze, record
   it in CMP; otherwise indicate that we've missed a use.   

References comparison_use::code, DF_REF_REG_USE, comparison_use::insn, comparison_use::loc, comparison::missing_uses, comparison::n_uses, targetm, and comparison::uses.

Referenced by find_comparisons_in_bb().

static bool gate_compare_elim_after_reload ( )

static

References targetm.

rtl_opt_pass* make_pass_compare_elim_after_reload

(

)

static rtx maybe_select_cc_mode ( struct comparison *  cmp, rtx  a, rtx  b  )

static

Select an alternate CC_MODE for a comparison insn comparing A and B.
   Note that inputs are almost certainly different than the IN_A and IN_B
   stored in CMP -- we're called while attempting to eliminate the compare
   after all.  Return the new FLAGS rtx if successful, else return NULL.
   Note that this function may start a change group.   

References comparison_use::code, gen_rtx_REG(), comparison_use::insn, comparison_use::loc, comparison::missing_uses, comparison::n_uses, new_mode(), comparison::orig_mode, targetm, comparison::uses, and validate_change().

Referenced by try_eliminate_compare().

static bool try_eliminate_compare ( )

static

Attempt to replace a comparison with a prior arithmetic insn that can
   compute the same flags value as the comparison itself.  Return true if
   successful, having made all rtl modifications necessary.   

References apply_change_group(), copy_rtx(), delete_insn(), DF_REF_CONDITIONAL, DF_REF_MAY_CLOBBER, DF_REF_MUST_CLOBBER, DF_REF_PARTIAL, DF_REF_PRE_POST_MODIFY, DF_REF_SIGN_EXTRACT, DF_REF_STRICT_LOW_PART, DF_REF_ZERO_EXTRACT, find_reg_note(), find_regno_note(), gen_rtx_REG(), comparison::in_a, comparison::in_b, comparison::insn, maybe_select_cc_mode(), comparison::orig_mode, comparison::prev_clobber, remove_note(), rtx_equal_p(), targetm, and validate_change().

Referenced by execute_compare_elim_after_reload().

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Variable Documentation

vec<comparison_struct_p> all_compares

static