Performance regression 7.0 -> 7.2 (still in 7.4)

The program in nofib/parallel/blackscholes regressed quite badly in performance between 7.0.x and 7.2.1. This is just sequential performance, no parallelism.

With 7.0:

   3,084,786,008 bytes allocated in the heap
       5,150,592 bytes copied during GC
      33,741,048 bytes maximum residency (7 sample(s))
       1,541,904 bytes maximum slop
              64 MB total memory in use (2 MB lost due to fragmentation)

  Generation 0:  5760 collections,     0 parallel,  0.08s,  0.08s elapsed
  Generation 1:     7 collections,     0 parallel,  0.01s,  0.01s elapsed

  INIT  time    0.00s  (  0.00s elapsed)
  MUT   time   17.43s  ( 17.47s elapsed)
  GC    time    0.09s  (  0.09s elapsed)
  EXIT  time    0.00s  (  0.00s elapsed)
  Total time   17.53s  ( 17.56s elapsed)

With 7.2.2:

   3,062,127,752 bytes allocated in the heap
       4,714,784 bytes copied during GC
      34,370,232 bytes maximum residency (7 sample(s))
       1,553,968 bytes maximum slop
              64 MB total memory in use (2 MB lost due to fragmentation)

                                    Tot time (elapsed)  Avg pause  Max pause
  Gen  0      5781 colls,     0 par    0.08s    0.08s     0.0000s    0.0006s
  Gen  1         7 colls,     0 par    0.01s    0.01s     0.0014s    0.0017s

  INIT    time    0.00s  (  0.00s elapsed)
  MUT     time   23.93s  ( 23.93s elapsed)
  GC      time    0.09s  (  0.09s elapsed)
  EXIT    time    0.00s  (  0.00s elapsed)
  Total   time   24.02s  ( 24.03s elapsed)

and with 7.4.1:

   3,061,924,144 bytes allocated in the heap
       4,733,760 bytes copied during GC
      34,210,896 bytes maximum residency (7 sample(s))
       1,552,640 bytes maximum slop
              64 MB total memory in use (2 MB lost due to fragmentation)

                                    Tot time (elapsed)  Avg pause  Max pause
  Gen  0      5781 colls,     0 par    0.08s    0.08s     0.0000s    0.0007s
  Gen  1         7 colls,     0 par    0.01s    0.01s     0.0015s    0.0017s

  INIT    time    0.00s  (  0.00s elapsed)
  MUT     time   23.90s  ( 23.91s elapsed)
  GC      time    0.09s  (  0.09s elapsed)
  EXIT    time    0.00s  (  0.00s elapsed)
  Total   time   24.00s  ( 24.00s elapsed)

Trac metadata

Trac field	Value
Version	7.4.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	high
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture