[Bug tree-optimization/32698] New: [4.3 regression] inefficient pointer expression
zippel at gcc dot gnu dot org
gcc-bugzilla@gcc.gnu.org
Mon Jul 9 13:25:00 GMT 2007
Taking this example:
int foo(int *p, unsigned int i)
{
return p[i + 1] + p[i + 2] + p[i + 3];
}
produces inefficient code. The problem already starts at tree level, where for
"p[i+1]" an expression like *(p + (i + 1) * 4)) is generated, which is not a
common pointer expression.
Also since this is different from the other generated pointer expression, the
common index expression isn't completely replaced.
An initial discussion about this can be found here:
http://gcc.gnu.org/ml/gcc-patches/2007-07/msg00418.html
--
Summary: [4.3 regression] inefficient pointer expression
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: zippel at gcc dot gnu dot org
GCC host triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32698
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