1.1 --- a/src/share/vm/opto/gcm.cpp Wed Jan 07 11:23:28 2009 -0800
1.2 +++ b/src/share/vm/opto/gcm.cpp Tue Jan 13 11:10:00 2009 -0800
1.3 @@ -29,6 +29,9 @@
1.4 #include "incls/_precompiled.incl"
1.5 #include "incls/_gcm.cpp.incl"
1.6
1.7 +// To avoid float value underflow
1.8 +#define MIN_BLOCK_FREQUENCY 1.e-35f
1.9 +
1.10 //----------------------------schedule_node_into_block-------------------------
1.11 // Insert node n into block b. Look for projections of n and make sure they
1.12 // are in b also.
1.13 @@ -1380,6 +1383,13 @@
1.14 }
1.15 }
1.16
1.17 +#ifdef ASSERT
1.18 + for (uint i = 0; i < _num_blocks; i++ ) {
1.19 + Block *b = _blocks[i];
1.20 + assert(b->_freq >= MIN_BLOCK_FREQUENCY, "Register Allocator requiers meaningful block frequency");
1.21 + }
1.22 +#endif
1.23 +
1.24 #ifndef PRODUCT
1.25 if (PrintCFGBlockFreq) {
1.26 tty->print_cr("CFG Block Frequencies");
1.27 @@ -1877,7 +1887,9 @@
1.28 float loop_freq = _freq * trip_count();
1.29 for (int i = 0; i < _members.length(); i++) {
1.30 CFGElement* s = _members.at(i);
1.31 - s->_freq *= loop_freq;
1.32 + float block_freq = s->_freq * loop_freq;
1.33 + if (block_freq < MIN_BLOCK_FREQUENCY) block_freq = MIN_BLOCK_FREQUENCY;
1.34 + s->_freq = block_freq;
1.35 }
1.36 CFGLoop* ch = _child;
1.37 while (ch != NULL) {
