[Bug tree-optimization/16987] [3.5 Regression] Excessive stack allocation (totally unused)

giovannibajo at libero dot it gcc-bugzilla@gcc.gnu.org
Wed Aug 11 19:44:00 GMT 2004


------- Additional Comments From giovannibajo at libero dot it  2004-08-11 19:44 -------
The stack allocation problem is present in GCC since at least GCC 3.2.2, and 
the tree optimizers didn't fix it.

2.95.3 allocated more stack space without the constructor but less stack space 
with the constructor:

-       subl $20,%esp
+       subl $36,%esp

So we now allocate 64 bytes instead of 36. I flag this as a regression, which 
is surely important for any kind of embedded targets.

The missed optimization which Andrew speaks about in comment #1 is a known 
problem already tracked elsewhere (as he said).

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |3.3.3 3.4.0 3.5.0
      Known to work|                            |2.95.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16987



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