The main regression was introduced with Chuck's putback:
20070712074224.rasbold.c2_baseline0
which fixed 6510732: Compute consistent block frequencies.

Additional small regression was added by John's putback:
20070719212032.jrose.6337834
which had several fixes (main 6337834: JVM should remove unneeded zeroing).

hsdev-3% cp /net/prt-archiver/data/archived_workspaces/main/c2_baseline/2007/20070711185532.kvn.6579347/solaris_amd64_compiler2/product/libjvm.so.gz ./ ; gunzip -f libjvm.so.gz
hsdev-3% gamma jnt.scimark2.commandline
Composite Score: 493.90508302589535
FFT (1024): 295.0339288063497
SOR (100x100): 633.2418727802554
Monte Carlo : 170.86916576831587
Sparse matmult (N=1000, nz=5000): 407.1823419814072
LU (100x100): 963.198105793148

hsdev-3% cp /net/prt-archiver/data/archived_workspaces/main/c2_baseline/2007/20070712074224.rasbold.c2_baseline0/solaris_amd64_compiler2/product/libjvm.so.gz ./ ; gunzip -f libjvm.so.gz
hsdev-3% gamma jnt.scimark2.commandline
Composite Score: 391.8510041234566
FFT (1024): 298.26276080862385
SOR (100x100): 631.7885370905
Monte Carlo : 173.40790641588111
Sparse matmult (N=1000, nz=5000): 279.9487302749625
LU (100x100): 575.847086027316

...

hsdev-3% cp /net/prt-archiver/data/archived_workspaces/main/c2_baseline/2007/20070718073059.nips.bug6579537-7/solaris_amd64_compiler2/product/libjvm.so.gz ./ ; gunzip -f libjvm.so.gz
hsdev-3% gamma jnt.scimark2.commandline
Composite Score: 392.4321377079277
FFT (1024): 290.99777314160036
SOR (100x100): 631.5814268475744
Monte Carlo : 173.35191825601459
Sparse matmult (N=1000, nz=5000): 290.62529314015256
LU (100x100): 575.6042771542966

hsdev-3% cp /net/prt-archiver/data/archived_workspaces/main/c2_baseline/2007/20070719212032.jrose.6337834/solaris_amd64_compiler2/product/libjvm.so.gz ./ ; gunzip -f libjvm.so.gz
hsdev-3% gamma jnt.scimark2.commandline
Composite Score: 376.36365792106426
FFT (1024): 245.5293662051119
SOR (100x100): 634.2840985767816
Monte Carlo : 172.294904635646
Sparse matmult (N=1000, nz=5000): 269.91763064562537
LU (100x100): 559.7922895421565