On 2021-10-20 10:44, Andrew Pinski wrote:
On Tue, Oct 19, 2021 at 7:30 PM Jiufu Guo via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
In tree_simplify_using_condition_1, there is code which should be
logic:
"op0 || op1"/"op0 && op1". When creating expression for TRUTH_OR_EXPR
and TRUTH_AND_EXPR, fold_build2 would be used instead fold_binary
which
always return NULL_TREE for this kind of expr.
Bootstrap and regtest pass on ppc and ppc64le. Is this ok for trunk?
No, because I think it is the wrong thing to do as we will be throwing
away the result if the fold_binary is not an integer cst anyways so
creating an extra tree is a waste.
Hi Andrew,
Thanks for your great comments! I understand your explanation. And
there
is already non-nullness checking and zero/nonzero cst checking as you
said.
I agree with you now :) because if "op0 && op1"/"op0 || op1" is able to
be folded (especially folded into a cst nonzero/zero), fold_binary is
enough.
And then, when fold_build2 creates a tree expr on code _AND_/_OR_, it
should
not be a cst anymore.
BR,
Jiufu
BR,
Jiufu
gcc/ChangeLog:
* tree-ssa-loop-niter.c (tree_simplify_using_condition_1):
Replace
fold_binary with fold_build2 fir logical OR/AND.
---
gcc/tree-ssa-loop-niter.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/gcc/tree-ssa-loop-niter.c b/gcc/tree-ssa-loop-niter.c
index 75109407124..27e11a29707 100644
--- a/gcc/tree-ssa-loop-niter.c
+++ b/gcc/tree-ssa-loop-niter.c
@@ -2290,12 +2290,12 @@ tree_simplify_using_condition_1 (tree cond,
tree expr)
/* Check whether COND ==> EXPR. */
notcond = invert_truthvalue (cond);
- e = fold_binary (TRUTH_OR_EXPR, boolean_type_node, notcond, expr);
+ e = fold_build2 (TRUTH_OR_EXPR, boolean_type_node, notcond, expr);
if (e && integer_nonzerop (e))
return e;
We already check for non-nullness and we also check to see it is an
integer which is nonzero. So building a tree which will be thrown away
is just a waste and all.
/* Check whether COND ==> not EXPR. */
- e = fold_binary (TRUTH_AND_EXPR, boolean_type_node, cond, expr);
+ e = fold_build2 (TRUTH_AND_EXPR, boolean_type_node, cond, expr);
if (e && integer_zerop (e))
return e;
Likewise.
Thanks,
Andrew Pinski
--
2.17.1
