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-rw-r--r--Python/bytecodes.c29
1 files changed, 16 insertions, 13 deletions
diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index f7c7e36..2ad5878 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -2318,13 +2318,16 @@ dummy_func(
assert(oparg <= INSTR_OFFSET());
JUMPBY(-oparg);
#if ENABLE_SPECIALIZATION
- this_instr[1].cache += (1 << OPTIMIZER_BITS_IN_COUNTER);
+ uint16_t counter = this_instr[1].cache;
+ this_instr[1].cache = counter + (1 << OPTIMIZER_BITS_IN_COUNTER);
/* We are using unsigned values, but we really want signed values, so
- * do the 2s complement comparison manually */
- uint16_t ucounter = this_instr[1].cache + (1 << 15);
- uint16_t threshold = tstate->interp->optimizer_backedge_threshold + (1 << 15);
+ * do the 2s complement adjustment manually */
+ uint32_t offset_counter = counter ^ (1 << 15);
+ uint32_t threshold = tstate->interp->optimizer_backedge_threshold;
+ assert((threshold & OPTIMIZER_BITS_MASK) == 0);
+ // Use '>=' not '>' so that the optimizer/backoff bits do not effect the result.
// Double-check that the opcode isn't instrumented or something:
- if (ucounter > threshold && this_instr->op.code == JUMP_BACKWARD) {
+ if (offset_counter >= threshold && this_instr->op.code == JUMP_BACKWARD) {
OPT_STAT_INC(attempts);
_Py_CODEUNIT *start = this_instr;
/* Back up over EXTENDED_ARGs so optimizer sees the whole instruction */
@@ -2338,18 +2341,18 @@ dummy_func(
// Rewind and enter the executor:
assert(start->op.code == ENTER_EXECUTOR);
next_instr = start;
- this_instr[1].cache &= ((1 << OPTIMIZER_BITS_IN_COUNTER) - 1);
+ this_instr[1].cache &= OPTIMIZER_BITS_MASK;
}
else {
- int backoff = this_instr[1].cache & ((1 << OPTIMIZER_BITS_IN_COUNTER) - 1);
- if (backoff < MINIMUM_TIER2_BACKOFF) {
- backoff = MINIMUM_TIER2_BACKOFF;
+ int backoff = this_instr[1].cache & OPTIMIZER_BITS_MASK;
+ backoff++;
+ if (backoff < MIN_TIER2_BACKOFF) {
+ backoff = MIN_TIER2_BACKOFF;
}
- else if (backoff < 15 - OPTIMIZER_BITS_IN_COUNTER) {
- backoff++;
+ else if (backoff > MAX_TIER2_BACKOFF) {
+ backoff = MAX_TIER2_BACKOFF;
}
- assert(backoff <= 15 - OPTIMIZER_BITS_IN_COUNTER);
- this_instr[1].cache = ((1 << 16) - ((1 << OPTIMIZER_BITS_IN_COUNTER) << backoff)) | backoff;
+ this_instr[1].cache = ((UINT16_MAX << OPTIMIZER_BITS_IN_COUNTER) << backoff) | backoff;
}
}
#endif /* ENABLE_SPECIALIZATION */