[Bug tree-optimization/37101] [4.2/4.3 Regression] wrong code: tree vectorizer omits bogus movq/movlps construct

[christophe at saout dot de]

------- Comment #3 from christophe at saout dot de  2008-08-13 16:14 -------
Ok, tried that...

Now xorg-server doesn't segfault, but hang in an infinite loop.

Adding printouts after the loop shows that the upper and lower parts of the
register are inverted:

(contents of the "tails" array):
  0 0x28e1c98
  1 0x28e1c90
  2 0x28e1ca8
  3 0x28e1ca0
  4 0x28e1cb8
...

So, the movlps is correct to fill the lower half of the register without
touching the upper half, but the "movd %rax, %xmm1" should fill the upper half
instead. I tried changing it into a movhps, but that won't take the %rax as
source register.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37101