While looking at some MIPS code I found that GCC was not making optimal
use of the MIPS nor instruction. If you compile this function:
int f (int a, int b) { return ~(a|b); }
It generates:
or $2,$4,$5
nor $2,$0,$2
instead of just:
nor $2,$4,$5
Good spot!
Steve Ellcey sell...@mips.com writes:
diff --git a/gcc/config/mips/mips.c b/gcc/config/mips/mips.c
index 5993aab..ffb0b53 100644
--- a/gcc/config/mips/mips.c
+++ b/gcc/config/mips/mips.c
@@ -3796,6 +3796,18 @@ mips_rtx_costs (rtx x, int code, int outer_code, int
opno
On Tue, 2013-10-22 at 18:34 +0100, Richard Sandiford wrote:
Good spot!
We should use set_src_cost for both operands (the idea being that only
a register is allowed, and that anything else will end up being a SET_SRC).
I think the formatting should be something like:
/* (AND (NOT op0)
Steve Ellcey sell...@mips.com writes:
On Tue, 2013-10-22 at 18:34 +0100, Richard Sandiford wrote:
Good spot!
We should use set_src_cost for both operands (the idea being that only
a register is allowed, and that anything else will end up being a SET_SRC).
I think the formatting should be
On Tue, 2013-10-22 at 19:12 +0100, Richard Sandiford wrote:
Richard
OK, but I am curious why you put parenthesis around the right hand side
of the total expression. I.e. *total = ();
That's the emacs formatting rule:
OK, I have checked in the patch with the parenthesis (and your
