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| author | Jakub Jelinek <jakub@redhat.com> | 2023-08-30 10:47:21 +0200 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2023-08-30 10:47:21 +0200 |
| commit | 49a3b35c4068091900b657cd36e5cffd41ef0c47 (patch) | |
| tree | 9cd98fd9070619aabedc849ab946b939e5eba950 | |
| parent | 0394184cebc15e5e3f13d04d9ffbc787a16018bd (diff) | |
| download | gcc-49a3b35c4068091900b657cd36e5cffd41ef0c47.zip gcc-49a3b35c4068091900b657cd36e5cffd41ef0c47.tar.gz gcc-49a3b35c4068091900b657cd36e5cffd41ef0c47.tar.bz2 | |
store-merging: Fix up >= 64 bit insertion [PR111015]
The following testcase shows that we mishandle bit insertion for
info->bitsize >= 64. The problem is in using unsigned HOST_WIDE_INT
shift + subtraction + build_int_cst to compute mask, the shift invokes
UB at compile time for info->bitsize 64 and larger and e.g. on the testcase
with info->bitsize happens to compute mask of 0x3f rather than
0x3f'ffffffff'ffffffff.
The patch fixes that by using wide_int wi::mask + wide_int_to_tree, so it
handles masks in any precision (up to WIDE_INT_MAX_PRECISION ;) ).
2023-08-30 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/111015
* gimple-ssa-store-merging.cc
(imm_store_chain_info::output_merged_store): Use wi::mask and
wide_int_to_tree instead of unsigned HOST_WIDE_INT shift and
build_int_cst to build BIT_AND_EXPR mask.
* gcc.dg/pr111015.c: New test.
| -rw-r--r-- | gcc/gimple-ssa-store-merging.cc | 9 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/pr111015.c | 28 |
2 files changed, 33 insertions, 4 deletions
diff --git a/gcc/gimple-ssa-store-merging.cc b/gcc/gimple-ssa-store-merging.cc index 0d19b98..542958d 100644 --- a/gcc/gimple-ssa-store-merging.cc +++ b/gcc/gimple-ssa-store-merging.cc @@ -4687,12 +4687,13 @@ imm_store_chain_info::output_merged_store (merged_store_group *group) } else if ((BYTES_BIG_ENDIAN ? start_gap : end_gap) > 0) { - const unsigned HOST_WIDE_INT imask - = (HOST_WIDE_INT_1U << info->bitsize) - 1; + wide_int imask + = wi::mask (info->bitsize, false, + TYPE_PRECISION (TREE_TYPE (tem))); tem = gimple_build (&seq, loc, BIT_AND_EXPR, TREE_TYPE (tem), tem, - build_int_cst (TREE_TYPE (tem), - imask)); + wide_int_to_tree (TREE_TYPE (tem), + imask)); } const HOST_WIDE_INT shift = (BYTES_BIG_ENDIAN ? end_gap : start_gap); diff --git a/gcc/testsuite/gcc.dg/pr111015.c b/gcc/testsuite/gcc.dg/pr111015.c new file mode 100644 index 0000000..599a14e --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr111015.c @@ -0,0 +1,28 @@ +/* PR tree-optimization/111015 */ +/* { dg-do run { target int128 } } */ +/* { dg-options "-O2" } */ + +struct S { unsigned a : 4, b : 4; unsigned __int128 c : 70; } d; + +__attribute__((noipa)) void +foo (unsigned __int128 x, unsigned char y, unsigned char z) +{ + d.a = y; + d.b = z; + d.c = x; +} + +int +main () +{ + foo (-1, 12, 5); + if (d.a != 12 + || d.b != 5 + || d.c != (-1ULL | (((unsigned __int128) 0x3f) << 64))) + __builtin_abort (); + foo (0x123456789abcdef0ULL | (((unsigned __int128) 26) << 64), 7, 11); + if (d.a != 7 + || d.b != 11 + || d.c != (0x123456789abcdef0ULL | (((unsigned __int128) 26) << 64))) + __builtin_abort (); +} |