[Bug middle-end/17503] [4.0 Regression] Huge performance regression in invalid_mode_change_p

[drow at gcc dot gnu dot org]

------- Additional Comments From drow at gcc dot gnu dot org  2004-09-20 19:23 -------
Yes, Roger's patch is innocent.

Richard, I haven't narrowed it down to one patch yet, but it's down to the
six-hour window in which you committed the patch for PR 9997.  That's my
suspect.  There is no substantive difference in the RTL diffs except that
numbers for pseudoregisters get larger:
-(insn 9 8 10 1 (set (reg:SI 59 [ T.665 ])
+(insn 9 8 10 1 (set (reg:SI 11374 [ T.665 ])
         (mem/s/j:SI (plus:SI (reg/f:SI 11377)

and stack offsets fluctuate a bit.

I'll verify that I've pegged the right patch.  Do we need to do this at -O0?

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                 CC|                            |rth at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17503