diff options
Diffstat (limited to 'gcc/global.c')
| -rw-r--r-- | gcc/global.c | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/gcc/global.c b/gcc/global.c index 6f84ebffa8b..59cb642f959 100644 --- a/gcc/global.c +++ b/gcc/global.c @@ -38,6 +38,14 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA #include "output.h" #include "toplev.h" +/* APPLE LOCAL begin rewrite weight computation */ +/* The rewritten weight computation works fine on Darwin, but causes + bootstrap compares to fail on Linux. */ +#ifdef CONFIG_DARWIN_H +#define REWRITE_WEIGHT_COMPUTATION +#endif +/* APPLE LOCAL end rewrite weight computation */ + /* This pass of the compiler performs global register allocation. It assigns hard register numbers to all the pseudo registers that were not handled in local_alloc. Assignments are recorded @@ -226,6 +234,18 @@ static HARD_REG_SET regs_used_so_far; static int local_reg_n_refs[FIRST_PSEUDO_REGISTER]; +/* APPLE LOCAL begin rewrite weight computation */ +#ifdef REWRITE_WEIGHT_COMPUTATION +/* Overall weight of each hard reg, as used by local alloc. + This was formerly computed once as + SUM(REG_FREQ(i))/SUM(REG_LIVE_LENGTH(i)) where the sums + are computed over all uses. But that computation produces very + wrong answers when a reg is used both inside and outside a loop. + Now it is computed as + SUM (REG_FREQ(i)/REG_LIVE_LENGTH(i)) over all uses. */ + +static double local_reg_weight[FIRST_PSEUDO_REGISTER]; +#else /* Frequency of uses of given hard reg. */ static int local_reg_freq[FIRST_PSEUDO_REGISTER]; @@ -233,6 +253,8 @@ static int local_reg_freq[FIRST_PSEUDO_REGISTER]; This is actually the sum of the live lengths of the specific regs. */ static int local_reg_live_length[FIRST_PSEUDO_REGISTER]; +#endif /* REWRITE_WEIGHT_COMPUTATION */ +/* APPLE LOCAL end rewrite weight computation */ /* Set to 1 a bit in a vector TABLE of HARD_REG_SETs, for vector element I, and hard register number J. */ @@ -478,9 +500,17 @@ global_alloc (FILE *file) /* Calculate amount of usage of each hard reg by pseudos allocated by local-alloc. This is to see if we want to override it. */ + /* APPLE LOCAL begin rewrite weight computation */ +#ifndef REWRITE_WEIGHT_COMPUTATION memset (local_reg_live_length, 0, sizeof local_reg_live_length); +#endif /* REWRITE_WEIGHT_COMPUTATION */ memset (local_reg_n_refs, 0, sizeof local_reg_n_refs); +#ifdef REWRITE_WEIGHT_COMPUTATION + memset (local_reg_weight, 0, sizeof local_reg_weight); +#else memset (local_reg_freq, 0, sizeof local_reg_freq); +#endif /* REWRITE_WEIGHT_COMPUTATION */ + /* APPLE LOCAL end rewrite weight computation */ for (i = FIRST_PSEUDO_REGISTER; i < (size_t) max_regno; i++) if (reg_renumber[i] >= 0) { @@ -491,15 +521,29 @@ global_alloc (FILE *file) for (j = regno; j < endregno; j++) { local_reg_n_refs[j] += REG_N_REFS (i); + /* APPLE LOCAL begin rewrite weight computation */ +#ifdef REWRITE_WEIGHT_COMPUTATION + if ( REG_LIVE_LENGTH (i) > 0 ) + local_reg_weight[j] += (double)REG_FREQ (i) + / (double) REG_LIVE_LENGTH (i); +#else local_reg_freq[j] += REG_FREQ (i); local_reg_live_length[j] += REG_LIVE_LENGTH (i); +#endif /* REWRITE_WEIGHT_COMPUTATION */ + /* APPLE LOCAL end rewrite weight computation */ } } /* We can't override local-alloc for a reg used not just by local-alloc. */ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) if (regs_ever_live[i]) + /* APPLE LOCAL begin rewrite weight computation */ +#ifdef REWRITE_WEIGHT_COMPUTATION + local_reg_n_refs[i] = 0; +#else local_reg_n_refs[i] = 0, local_reg_freq[i] = 0; +#endif /* REWRITE_WEIGHT_COMPUTATION */ + /* APPLE LOCAL end rewrite weight computation */ allocno_row_words = (max_allocno + INT_BITS - 1) / INT_BITS; @@ -1249,6 +1293,15 @@ find_reg (int num, HARD_REG_SET losers, int alt_regs_p, int accept_call_clobbere #endif ) { + /* APPLE LOCAL begin rewrite weight computation */ +#ifdef REWRITE_WEIGHT_COMPUTATION + /* We explicitly evaluate the divide result into a temporary + variable so as to avoid excess precision problems that occur + on an i386-unknown-sysv4.2 (unixware) host. */ + double tmp = ((double) allocno[num].freq + / allocno[num].live_length); +#else + /* APPLE LOCAL end rewrite weight computation */ /* We explicitly evaluate the divide results into temporary variables so as to avoid excess precision problems that occur on an i386-unknown-sysv4.2 (unixware) host. */ @@ -1257,8 +1310,15 @@ find_reg (int num, HARD_REG_SET losers, int alt_regs_p, int accept_call_clobbere / local_reg_live_length[regno]); double tmp2 = ((double) allocno[num].freq / allocno[num].live_length); + /* APPLE LOCAL begin rewrite weight computation */ +#endif /* REWRITE_WEIGHT_COMPUTATION */ +#ifdef REWRITE_WEIGHT_COMPUTATION + if (local_reg_weight[regno] < tmp) +#else if (tmp1 < tmp2) +#endif /* REWRITE_WEIGHT_COMPUTATION */ + /* APPLE LOCAL end rewrite weight computation */ { /* Hard reg REGNO was used less in total by local regs than it would be used by this one allocno! */ @@ -1305,7 +1365,11 @@ find_reg (int num, HARD_REG_SET losers, int alt_regs_p, int accept_call_clobbere SET_HARD_REG_BIT (regs_used_so_far, j); /* This is no longer a reg used just by local regs. */ local_reg_n_refs[j] = 0; + /* APPLE LOCAL begin rewrite weight computation */ +#ifndef REWRITE_WEIGHT_COMPUTATION local_reg_freq[j] = 0; +#endif /* REWRITE_WEIGHT_COMPUTATION */ + /* APPLE LOCAL end rewrite weight computation */ } /* For each other pseudo-reg conflicting with this one, mark it as conflicting with the hard regs this one occupies. */ |