On Thu, Apr 29, 2021 at 8:52 AM Jeff Law <jeffreya...@gmail.com> wrote:
>
> This change:
>
> 985b3a6837dee7001e6b618f073ed74f0edf5787 is the first bad commit
> commit 985b3a6837dee7001e6b618f073ed74f0edf5787
> Author: H.J. Lu <hjl.to...@gmail.com>
> Date: Mon Jun 10 09:57:15 2019 -0700
>
> Generate offset adjusted operation for op_by_pieces operations
>
> Add an overlap_op_by_pieces_p target hook for op_by_pieces operations
> between two areas of memory to generate one offset adjusted operation
> in the smallest integer mode for the remaining bytes on the last piece
> operation of a memory region to avoid doing more than one smaller
> operations.
>
> Pass the RTL information from the previous iteration to m_constfn in
> op_by_pieces operation so that builtin_memset_[read|gen]_str can
> generate the new RTL from the previous RTL.
>
> Tested on Linux/x86-64.
>
> gcc/
>
> PR middle-end/90773
> * builtins.c (builtin_memcpy_read_str): Add a dummy argument.
> (builtin_strncpy_read_str): Likewise.
> (builtin_memset_read_str): Add an argument for the previous RTL
> information and generate the new RTL from the previous RTL
> info.
> (builtin_memset_gen_str): Likewise.
> * builtins.h (builtin_strncpy_read_str): Update the prototype.
> (builtin_memset_read_str): Likewise.
> * expr.c (by_pieces_ninsns): If
> targetm.overlap_op_by_pieces_p()
> returns true, round up size and alignment to the widest integer
> mode for maximum size.
> (pieces_addr::adjust): Add a pointer to by_pieces_prev argument
> and pass it to m_constfn.
> (op_by_pieces_d): Add m_push and m_overlap_op_by_pieces.
> (op_by_pieces_d::op_by_pieces_d): Add a bool argument to
> initialize m_push. Initialize m_overlap_op_by_pieces with
> targetm.overlap_op_by_pieces_p ().
> (op_by_pieces_d::run): Pass the previous RTL information to
> pieces_addr::adjust and generate overlapping operations if
> m_overlap_op_by_pieces is true.
> (PUSHG_P): New.
> (move_by_pieces_d::move_by_pieces_d): Updated for
> op_by_pieces_d
> change.
> (store_by_pieces_d::store_by_pieces_d): Updated for
> op_by_pieces_d
> change.
> (can_store_by_pieces): Use by_pieces_constfn on constfun.
> (store_by_pieces): Use by_pieces_constfn on constfun. Updated
> for op_by_pieces_d change.
> (clear_by_pieces_1): Add a dummy argument.
> (clear_by_pieces): Updated for op_by_pieces_d change.
> (compare_by_pieces_d::compare_by_pieces_d): Likewise.
> (string_cst_read_str): Add a dummy argument.
> * expr.h (by_pieces_constfn): Add a dummy argument.
> (by_pieces_prev): New.
> * target.def (overlap_op_by_pieces_p): New target hook.
> * config/i386/i386.c (TARGET_OVERLAP_OP_BY_PIECES_P): New.
> * doc/tm.texi.in: Add TARGET_OVERLAP_OP_BY_PIECES_P.
> * doc/tm.texi: Regenerated.
>
>
> Is causing regressions on the fr30-elf port:
>
>
> fr30-sim: gcc.dg/Wstringop-overflow-27.c (test for warnings, line 168)
> fr30-sim: gcc.dg/Wstringop-overflow-27.c (test for warnings, line 174)
> fr30-sim: gcc.dg/Wstringop-overflow-27.c (test for warnings, line 180)
> fr30-sim: gcc.dg/Wstringop-overflow-27.c (test for warnings, line 186)
> fr30-sim: gcc.dg/Wstringop-overflow-27.c (test for warnings, line 193)
> fr30-sim: gcc.dg/Wstringop-overflow-27.c (test for warnings, line 201)
> fr30-sim: gcc.dg/Wstringop-overflow-27.c (test for warnings, line 265)
> fr30-sim: gcc.dg/Wstringop-overflow-27.c (test for warnings, line 274)
> fr30-sim: gcc.dg/Wstringop-overflow-27.c (test for warnings, line 282)
> fr30-sim: gcc.dg/Wstringop-overflow-27.c (test for warnings, line 289)
> fr30-sim: gcc.dg/Wstringop-overflow-27.c (test for excess errors)
> fr30-sim: gcc.dg/Wstringop-overflow-27.c malloc note (test for warnings,
> line 288)
> fr30-sim: gcc.dg/Wstringop-overflow-27.c note (test for warnings, line 264)
> fr30-sim: gcc.dg/Wstringop-overflow-27.c note (test for warnings, line 273)
> fr30-sim: gcc.dg/Wstringop-overflow-27.c vla note (test for warnings,
> line 281)
>
>
> I haven't done any analysis other then bisecting the regression.
>
>
> Full logs are here:
>
> http://3.14.90.209:8080/job/fr30-elf/1258/console
>
Check nullptr return from simplify_gen_subreg. Don't use it if it is
nullptr.
OK for master?
Thanks.
--
H.J.
From 7722dc817fb413f5a4887c8a38ab7b30ab39a33b Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Thu, 29 Apr 2021 11:12:09 -0700
Subject: [PATCH] Don't use nullptr return from simplify_gen_subreg
Check nullptr return from simplify_gen_subreg. Don't use it if it is
nullptr.
PR middle-end/90773
* builtins.c (builtin_memset_gen_str): Don't use return from
simplify_gen_subreg.
---
gcc/builtins.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/gcc/builtins.c b/gcc/builtins.c
index 2d6bf4a65b4..4613aecfe6e 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -6628,7 +6628,9 @@ builtin_memset_gen_str (void *data, void *prevp,
if (prev->mode == mode)
return prev->data;
- return simplify_gen_subreg (mode, prev->data, prev->mode, 0);
+ target = simplify_gen_subreg (mode, prev->data, prev->mode, 0);
+ if (target != nullptr)
+ return target;
}
size = GET_MODE_SIZE (mode);
--
2.31.1
