| Message ID | 23c7868a-6736-5c73-fa9a-05e3e5ef53d6@linux.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | combine: Check for paradoxical subreg | expand |
> gcc/ChangeLog: > > * combine.c (try_combine): Check for paradoxical subreg. ping.
Hi, pinging this patch: https://gcc.gnu.org/pipermail/gcc-patches/2021-June/573509.html It introduces a check for a paradoxical subreg in combine that would ICE otherwise. Regards Robin
Sorry for the slow review. Robin Dapp via Gcc-patches <gcc-patches@gcc.gnu.org> writes: > Hi, > > while evaluating another patch that introduces more lvalue paradoxical > subregs I ran into an ICE in combine at > > wide_int o = wi::insert (rtx_mode_t (outer, temp_mode), > rtx_mode_t (inner, dest_mode), > offset, width); > > because width (=GET_MODE_PRECISION (dest_mode)) > GET_MODE_PRECISION > (temp_mode). > > From the comments and the code it looks like we do not want to handle a > paradoxical subreg here so I quickly added a check for it which prevents > the ICE. The check could also be added to reg_subword_p () I guess. Yeah, I think adding it to reg_subword_p would be better, immediately after the GET_CODE (x) == SUBREG test. OK with that change, thanks. Richard > > Is this the right thing to do or am I missing something, i.e. my other > patch might be doing something it should not? > > Bootstrap on s390x was successful and testsuite is looking good so far. > > Regards > Robin > > -- > > gcc/ChangeLog: > > * combine.c (try_combine): Check for paradoxical subreg. > > From 2b74c66f8d97c30c45e99336c9871cccd8cf94e1 Mon Sep 17 00:00:00 2001 > From: Robin Dapp <rdapp@linux.ibm.com> > Date: Tue, 22 Jun 2021 17:35:37 +0200 > Subject: [PATCH 11/11] combine paradoxical subreg fix. > > --- > gcc/combine.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/gcc/combine.c b/gcc/combine.c > index 6476812a212..de04560db21 100644 > --- a/gcc/combine.c > +++ b/gcc/combine.c > @@ -2782,7 +2782,8 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, > && CONST_SCALAR_INT_P (SET_SRC (temp_expr)) > && GET_CODE (PATTERN (i3)) == SET > && CONST_SCALAR_INT_P (SET_SRC (PATTERN (i3))) > - && reg_subword_p (SET_DEST (PATTERN (i3)), SET_DEST (temp_expr))) > + && reg_subword_p (SET_DEST (PATTERN (i3)), SET_DEST (temp_expr)) > + && !paradoxical_subreg_p (SET_DEST (PATTERN (i3)))) > { > rtx dest = SET_DEST (PATTERN (i3)); > rtx temp_dest = SET_DEST (temp_expr);
From 2b74c66f8d97c30c45e99336c9871cccd8cf94e1 Mon Sep 17 00:00:00 2001 From: Robin Dapp <rdapp@linux.ibm.com> Date: Tue, 22 Jun 2021 17:35:37 +0200 Subject: [PATCH 11/11] combine paradoxical subreg fix. --- gcc/combine.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/gcc/combine.c b/gcc/combine.c index 6476812a212..de04560db21 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -2782,7 +2782,8 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, && CONST_SCALAR_INT_P (SET_SRC (temp_expr)) && GET_CODE (PATTERN (i3)) == SET && CONST_SCALAR_INT_P (SET_SRC (PATTERN (i3))) - && reg_subword_p (SET_DEST (PATTERN (i3)), SET_DEST (temp_expr))) + && reg_subword_p (SET_DEST (PATTERN (i3)), SET_DEST (temp_expr)) + && !paradoxical_subreg_p (SET_DEST (PATTERN (i3)))) { rtx dest = SET_DEST (PATTERN (i3)); rtx temp_dest = SET_DEST (temp_expr); -- 2.31.1
Hi, while evaluating another patch that introduces more lvalue paradoxical subregs I ran into an ICE in combine at wide_int o = wi::insert (rtx_mode_t (outer, temp_mode), rtx_mode_t (inner, dest_mode), offset, width); because width (=GET_MODE_PRECISION (dest_mode)) > GET_MODE_PRECISION (temp_mode). From the comments and the code it looks like we do not want to handle a paradoxical subreg here so I quickly added a check for it which prevents the ICE. The check could also be added to reg_subword_p () I guess. Is this the right thing to do or am I missing something, i.e. my other patch might be doing something it should not? Bootstrap on s390x was successful and testsuite is looking good so far. Regards Robin -- gcc/ChangeLog: * combine.c (try_combine): Check for paradoxical subreg.