[Bug rtl-optimization/24257] [4.1/4.2 Regression] ICE: in extract_insn with -O -fgcse -fgcse-sm

[steven at gcc dot gnu dot org]

------- Comment #13 from steven at gcc dot gnu dot org  2006-01-09 21:25 -------
Created an attachment (id=10601)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10601&action=view)
proposed fix

This is my throw-over-the-wall completely untested proposed fix
for PR24257.  We end up ICEing when we try to emit an invalid
SET insns where the SET_DEST is a REG and the SET_SRC is taken
from a store to a MEM.

When the SET_SRC of that store can't be assigned to a register,
we should not consider the store movable.  This happens for
example with x86/AMD64 memory read-modify-write instructions,
i.e. "MEM <- MEM op x".


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24257