| Message ID | 905c34de-6333-1021-05e6-942922918b18@linux.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] Return a NULL rtx when targets don't support cbranchcc4 or predicate check fails in prepare_cmp_insn | expand |
On Mon, Dec 5, 2022 at 4:08 AM HAO CHEN GUI <guihaoc@linux.ibm.com> wrote: > > Hi, > It gets an assertion failure when targers don't support cbranchcc4 or > predicate check fails in prepare_cmp_insn. prepare_cmp_insn is a help > function to generate compare rtx, so it should not assume that cbranchcc4 > is existing or all sub-CC modes are supported on one target. I think it > should return the NULL rtx when cbranchcc4 is not supported or predicate check > fails, as its callers already check if the return value is null or not for CC > mode. This patch just does the change. > > Bootstrapped and tested on powerpc64-linux BE/LE and x86 with no regressions. > Is this okay for trunk? Any recommendations? Thanks a lot. I wonder if you have a testcase you can add showing this change is worthwhile and fixes a bug? OK. Thanks, Richard. > > ChangeLog > 2022-12-05 Haochen Gui <guihaoc@linux.ibm.com> > > gcc/ > * optabs.cc (prepare_cmp_insn): Return a NULL rtx other than assertion > failure when targets don't have cbranch optab or predicate check > fails. > > patch.diff > diff --git a/gcc/optabs.cc b/gcc/optabs.cc > index 165f8d1fa22..f6d3242479b 100644 > --- a/gcc/optabs.cc > +++ b/gcc/optabs.cc > @@ -4484,10 +4484,14 @@ prepare_cmp_insn (rtx x, rtx y, enum rtx_code comparison, rtx size, > { > enum insn_code icode = optab_handler (cbranch_optab, CCmode); > test = gen_rtx_fmt_ee (comparison, VOIDmode, x, y); > - gcc_assert (icode != CODE_FOR_nothing > - && insn_operand_matches (icode, 0, test)); > - *ptest = test; > - return; > + if (icode != CODE_FOR_nothing > + && insn_operand_matches (icode, 0, test)) > + { > + *ptest = test; > + return; > + } > + else > + goto fail; > } > > mclass = GET_MODE_CLASS (mode);
Hi Richard, 在 2022/12/5 15:31, Richard Biener 写道: > I wonder if you have a testcase you can add showing this change is > worthwhile and > fixes a bug? I want to enable cbranchcc4 on rs6000. But not all sub CCmode is supported on rs6000. So the predicate check(assert) fails and it hits ICE. I drafted two patches. This one is for the generic code, and another is for rs6000. If this one is committed, cbranchcc4 can be enabled on rs6000. Then I can create a testcase and let the predicate check fail. Right now I can't write a testcase for it as it never reaches the failure path. Thanks a lot Gui Haochen
On Mon, Dec 5, 2022 at 9:43 AM HAO CHEN GUI <guihaoc@linux.ibm.com> wrote: > > Hi Richard, > > 在 2022/12/5 15:31, Richard Biener 写道: > > I wonder if you have a testcase you can add showing this change is > > worthwhile and > > fixes a bug? > > I want to enable cbranchcc4 on rs6000. But not all sub CCmode is > supported on rs6000. So the predicate check(assert) fails and it hits > ICE. I drafted two patches. This one is for the generic code, and > another is for rs6000. If this one is committed, cbranchcc4 can be > enabled on rs6000. Then I can create a testcase and let the predicate > check fail. Right now I can't write a testcase for it as it never > reaches the failure path. Fair enough. > Thanks a lot > Gui Haochen >
diff --git a/gcc/optabs.cc b/gcc/optabs.cc index 165f8d1fa22..f6d3242479b 100644 --- a/gcc/optabs.cc +++ b/gcc/optabs.cc @@ -4484,10 +4484,14 @@ prepare_cmp_insn (rtx x, rtx y, enum rtx_code comparison, rtx size, { enum insn_code icode = optab_handler (cbranch_optab, CCmode); test = gen_rtx_fmt_ee (comparison, VOIDmode, x, y); - gcc_assert (icode != CODE_FOR_nothing - && insn_operand_matches (icode, 0, test)); - *ptest = test; - return; + if (icode != CODE_FOR_nothing + && insn_operand_matches (icode, 0, test)) + { + *ptest = test; + return; + } + else + goto fail; } mclass = GET_MODE_CLASS (mode);