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[CVS 980326]: Bug in haifa scheduler on sparc-sun-solaris2.5.1
- To: egcs-bugs at cygnus dot com
- Subject: [CVS 980326]: Bug in haifa scheduler on sparc-sun-solaris2.5.1
- From: Manfred Hollstein <manfred at s-direktnet dot de>
- Date: Thu, 26 Mar 1998 15:06:22 +0100 (MET)
- Reply-To: Manfred Hollstein <manfred at s-direktnet dot de>, Manfred dot Hollstein at ks dot sel dot alcatel dot de
I just observed the following behaviour:
- configure'd egcs with --enable-haifa=yes
- bootstrapped using '-O9 -funroll-all-loops'
During `make check' cc1 runs into a tight loop while compiling
loop-2c.c and loop-2d.c with `-O2 -fomit-frame-pointer
-finline-functions' and either of `-funroll-loops' and
The loop happens in in haifa-sched.c between lines 1786 - 1812. This
code looks like:
while (tail >= 0)
if (head < 0)
head = tail;
child = queue[head];
if (degree[child] == 0)
degree[child] = -1;
rgn_bb_table[idx++] = child;
BLOCK_TO_BB (child) = ++count;
CONTAINING_RGN (child) = nr_regions;
queue[head] = queue[tail--];
fst_edge = current_edge = OUT_EDGES (child);
if (fst_edge > 0)
current_edge = NEXT_OUT (current_edge);
while (fst_edge != current_edge);
Attaching to the running cc1 showed, it's looping without ever
decrementing (not even touching) `tail's value. Apparently, all
`degree[child]' are unequal 0, which simply causes decrementing `head'
and once it's < 0, re-initializing it to the yet unchanged `tail'.
Interestingly, this doesn't happen on hppa1.1-hp-hpux10.20!
Has anybody else observed similar? Any fixes available?