From 6efcd26809361ac6110c0edb41f825cfe541734f Mon Sep 17 00:00:00 2001 From: Jan Hubicka Date: Wed, 12 Feb 2003 15:23:20 +0100 Subject: [PATCH] * predict.c (estimate_probability): Fix roundoff error. From-SVN: r62765 --- gcc/ChangeLog | 4 ++++ gcc/predict.c | 11 ++++++++--- 2 files changed, 12 insertions(+), 3 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index b81e4c8419c..45975656ad3 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,7 @@ +Wed Feb 12 15:19:42 CET 2003 Jan Hubicka + + * predict.c (estimate_probability): Fix roundoff error. + 2003-02-12 Kazu Hirata * config/h8300/h8300.md (a peephole2): Don't handle 65535. diff --git a/gcc/predict.c b/gcc/predict.c index b0170f30718..a0fc75ae6ab 100644 --- a/gcc/predict.c +++ b/gcc/predict.c @@ -449,14 +449,19 @@ estimate_probability (loops_info) if (simple_loop_p (loops_info, loop, &desc) && desc.const_iter) { + int prob; niter = desc.niter + 1; if (niter == 0) /* We might overflow here. */ niter = desc.niter; + prob = (REG_BR_PROB_BASE + - (REG_BR_PROB_BASE + niter /2) / niter); + /* Branch prediction algorithm gives 0 frequency for everything + after the end of loop for loop having 0 probability to finish. */ + if (prob == REG_BR_PROB_BASE) + prob = REG_BR_PROB_BASE - 1; predict_edge (desc.in_edge, PRED_LOOP_ITERATIONS, - REG_BR_PROB_BASE - - (REG_BR_PROB_BASE + niter /2) - / niter); + prob); } bbs = get_loop_body (loop); -- 2.30.2