The following replaces the last host double computation by using
int64_t instead to avoid overflow of 32bit (but capped to
REG_BR_PROB_BASE) values.
Bootstrapped and tested on x86_64-unknown-linux-gnu.
OK?
Thanks,
Richard.
PR middle-end/45273
* predict.cc (combine_predictions_for_insn): Use int64_t
math instead of double.
---
gcc/predict.cc | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/gcc/predict.cc b/gcc/predict.cc
index de8f9c2211f..2859f64964b 100644
--- a/gcc/predict.cc
+++ b/gcc/predict.cc
@@ -1046,13 +1046,14 @@ combine_predictions_for_insn (rtx_insn *insn,
basic_block bb)
+ (REG_BR_PROB_BASE - combined_probability)
* (REG_BR_PROB_BASE - probability));
- /* Use FP math to avoid overflows of 32bit integers. */
+ /* Use int64_t math to avoid overflows of 32bit integers. */
if (d == 0)
/* If one probability is 0% and one 100%, avoid division by zero. */
combined_probability = REG_BR_PROB_BASE / 2;
else
- combined_probability = (((double) combined_probability) * probability
- * REG_BR_PROB_BASE / d + 0.5);
+ combined_probability = ((((int64_t) combined_probability)
+ * probability
+ * REG_BR_PROB_BASE + (d / 2)) / d);
}
/* Decide which heuristic to use. In case we didn't match anything,
@@ -1399,14 +1400,14 @@ combine_predictions_for_bb (basic_block bb, bool
dry_run)
+ (REG_BR_PROB_BASE - combined_probability)
* (REG_BR_PROB_BASE - probability));
- /* Use FP math to avoid overflows of 32bit integers. */
+ /* Use int64_t math to avoid overflows of 32bit integers. */
if (d == 0)
/* If one probability is 0% and one 100%, avoid division by zero.
*/
combined_probability = REG_BR_PROB_BASE / 2;
else
- combined_probability = (((double) combined_probability)
- * probability
- * REG_BR_PROB_BASE / d + 0.5);
+ combined_probability = ((((int64_t) combined_probability)
+ * probability
+ * REG_BR_PROB_BASE + (d / 2)) / d);
}
}
--
2.51.0
