[Bug middle-end/32662] Significant extra code generation for 64x64=>128-bit multiply

[rask at sygehus dot dk]

------- Comment #4 from rask at sygehus dot dk  2007-07-07 16:08 -------
In reply to comment #1:
If you're splitting a multiword subreg (such as %rbx:%rcx) after reload, then
the prologue/epilogue code has no way of knowing that all use of %rbx is later
optimized away. I don't know if this is what's happening here, but that would
be the first thing I'd look for.

In reply to comment #2:
For both GCC 4.1.x and 4.2.x, the status is "regression fixes & docs only", so
unless some older release produced better code, this won't be fixed in GCC
4.1.x or 4.2.x.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32662