------- Comment #4 from rguenth at gcc dot gnu dot org 2009-11-27 13:22 -------
Actually it is some RTL optimization pass that miscompiles this (func_2).
With -fno-delete-null-pointer-checks we defer evaluating &g != 0 until
expansion which then exposes CCP opportunities.
With -O1 -fno-delete-null-pointer-checks -m32 -ftree-vrp -fno-if-conversion we
generate
func_2:
pushl %ebp
movl %esp, %ebp
cmpl $9, g
jg .L5
movl $1, g
jmp .L1
.L5:
movl $2, g
.L1:
popl %ebp
ret
which looks good apart from that we have deleted the comparison against p.
This seems to happen between initial/final RTL during expansion.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |matz at gcc dot gnu dot org
Component|tree-optimization |rtl-optimization
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42084
