Index: params.def =================================================================== --- params.def (revision 220916) +++ params.def (working copy) @@ -836,6 +836,11 @@ DEFPARAM (PARAM_LRA_MAX_CONSIDERED_RELOA "The max number of reload pseudos which are considered during spilling a non-reload pseudo", 500, 0, 0) +DEFPARAM (PARAM_LRA_INHERITANCE_EBB_PROBABILITY_CUTOFF, + "lra-inheritance-ebb-probability-cutoff", + "Minimal fall-through edge probability in percentage used to add BB to inheritance EEB in LRA", + 40, 0, 100) + /* Switch initialization conversion will refuse to create arrays that are bigger than this parameter times the number of switch branches. */ Index: params.h =================================================================== --- params.h (revision 220916) +++ params.h (working copy) @@ -202,6 +202,8 @@ extern void init_param_values (int *para PARAM_VALUE (PARAM_IRA_LOOP_RESERVED_REGS) #define LRA_MAX_CONSIDERED_RELOAD_PSEUDOS \ PARAM_VALUE (PARAM_LRA_MAX_CONSIDERED_RELOAD_PSEUDOS) +#define LRA_INHERITANCE_EBB_PROBABILITY_CUTOFF \ + PARAM_VALUE (PARAM_LRA_INHERITANCE_EBB_PROBABILITY_CUTOFF) #define SWITCH_CONVERSION_BRANCH_RATIO \ PARAM_VALUE (PARAM_SWITCH_CONVERSION_BRANCH_RATIO) #define LOOP_INVARIANT_MAX_BBS_IN_LOOP \ Index: lra-constraints.c =================================================================== --- lra-constraints.c (revision 220916) +++ lra-constraints.c (working copy) @@ -154,6 +154,7 @@ #include "df.h" #include "ira.h" #include "rtl-error.h" +#include "params.h" #include "lra-int.h" /* Value of LRA_CURR_RELOAD_NUM at the beginning of BB of the current @@ -5694,7 +5695,8 @@ inherit_in_ebb (rtx_insn *head, rtx_insn /* This value affects EBB forming. If probability of edge from EBB to a BB is not greater than the following value, we don't add the BB to EBB. */ -#define EBB_PROBABILITY_CUTOFF ((REG_BR_PROB_BASE * 50) / 100) +#define EBB_PROBABILITY_CUTOFF \ + ((REG_BR_PROB_BASE * LRA_INHERITANCE_EBB_PROBABILITY_CUTOFF) / 100) /* Current number of inheritance/split iteration. */ int lra_inheritance_iter; @@ -5740,7 +5742,7 @@ lra_inheritance (void) e = find_fallthru_edge (bb->succs); if (! e) break; - if (e->probability <= EBB_PROBABILITY_CUTOFF) + if (e->probability < EBB_PROBABILITY_CUTOFF) break; bb = bb->next_bb; } Index: doc/invoke.texi =================================================================== --- doc/invoke.texi (revision 220916) +++ doc/invoke.texi (working copy) @@ -10570,6 +10570,14 @@ by this parameter. The default value of the minimal number of registers needed by typical instructions. This value is the best found from numerous experiments. +@item lra-inheritance-ebb-probability-cutoff +LRA tries to reuse values reloaded in registers in subsequent insns. +This optimization is called inheritance. EBB is used as a region to +do this optimization. The parameter defines a minimal fall-through +edge probability in percentage used to add BB to inheritance EBB in +LRA. The default value of the parameter is 40. The value was chosen +from numerous runs of SPEC2000 on x86-64. + @item loop-invariant-max-bbs-in-loop Loop invariant motion can be very expensive, both in compilation time and in amount of needed compile-time memory, with very large loops. Loops