expr.c: don't assume MUL for scaling pointers
DJ Delorie
dj@redhat.com
Thu Nov 3 03:33:00 GMT 2011
GCC assumes the target has a multiply insn, but better code is
generated using shifts if it doesn't (vs a libcall). Found with the
rl78-elf port.
* expr.c (expand_expr_real_2): Don't try to emit a MUL-based
expression if the target doesn't have a multiply pattern. Fall
back to shifts instead of using libgcc calls.
Index: gcc/expr.c
===================================================================
--- gcc/expr.c (revision 180758)
+++ gcc/expr.c (working copy)
@@ -8289,12 +8289,13 @@ expand_expr_real_2 (sepops ops, rtx targ
}
/* Attempt to return something suitable for generating an
indexed address, for machines that support that. */
if (modifier == EXPAND_SUM && mode == ptr_mode
+ && optab_handler (smul_optab, mode) != CODE_FOR_nothing
&& host_integerp (treeop1, 0))
{
tree exp1 = treeop1;
op0 = expand_expr (treeop0, subtarget, VOIDmode,
EXPAND_SUM);
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