| Message ID | 20211020022916.131643-1-guojiufu@linux.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | Use fold_build2 instead fold_binary for TRUTH_AND | expand |
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. > > 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 >
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 >>
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; /* 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;