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| author | Bin Cheng <bin.cheng@linux.alibaba.com> | 2021-07-28 17:50:59 +0800 |
|---|---|---|
| committer | Bin Cheng <bin.cheng@linux.alibaba.com> | 2021-07-28 17:50:59 +0800 |
| commit | b662250c1f5e0e453f1fd6022cc47e517f70fa8e (patch) | |
| tree | 9a846383080e6e786aa9a9c2aa13d72ebd702ae3 /gcc | |
| parent | 0f95c6b2f7dae35ec8c9f211d63edc42baa1d2b7 (diff) | |
| download | gcc-b662250c1f5e0e453f1fd6022cc47e517f70fa8e.zip gcc-b662250c1f5e0e453f1fd6022cc47e517f70fa8e.tar.gz gcc-b662250c1f5e0e453f1fd6022cc47e517f70fa8e.tar.bz2 | |
AArch64: use stable sorting in generating ldp/stp
In some corner cases, we have code as below:
[base + 0x310] = A
[base + 0x320] = B
[base + 0x330] = C
[base + 0x320] = D
unstable sorting could result in wrong value in offset 0x320. The
patch fixes it by using gcc_stablesort.
2021-07-28 Bin Cheng <bin.cheng@linux.alibaba.com>
* config/aarch64/aarch64.c (aarch64_gen_adjusted_ldpstp): use
gcc_stablesort.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/config/aarch64/aarch64.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c index 3bdf19d..e211460 100644 --- a/gcc/config/aarch64/aarch64.c +++ b/gcc/config/aarch64/aarch64.c @@ -24441,8 +24441,16 @@ aarch64_gen_adjusted_ldpstp (rtx *operands, bool load, for (int i = 0; i < 8; i ++) temp_operands[i] = operands[i]; - /* Sort the operands. */ - qsort (temp_operands, 4, 2 * sizeof (rtx *), aarch64_ldrstr_offset_compare); + /* Sort the operands. Note for cases as below: + [base + 0x310] = A + [base + 0x320] = B + [base + 0x330] = C + [base + 0x320] = D + We need stable sorting otherwise wrong data may be store to offset 0x320. + Also note the dead store in above case should be optimized away, but no + guarantees here. */ + gcc_stablesort(temp_operands, 4, 2 * sizeof (rtx *), + aarch64_ldrstr_offset_compare); /* Copy the memory operands so that if we have to bail for some reason the original addresses are unchanged. */ |