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| author | Jakub Jelinek <jakub@redhat.com> | 2020-05-06 09:31:19 +0200 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2020-05-06 09:31:19 +0200 |
| commit | f14848aea70066777faf201c0b6eb3c5520bfab9 (patch) | |
| tree | 40a788d722939d41065beb0c1b63add3e11e28e6 /gcc | |
| parent | 366386c7a970bf6a32c5a2abb714ca6c7f4e7790 (diff) | |
| download | gcc-f14848aea70066777faf201c0b6eb3c5520bfab9.zip gcc-f14848aea70066777faf201c0b6eb3c5520bfab9.tar.gz gcc-f14848aea70066777faf201c0b6eb3c5520bfab9.tar.bz2 | |
combine: Don't replace SET_SRC with REG_EQUAL note content if SET_SRC has side-effects [PR94873]
There were some discussions about whether REG_EQUAL notes are valid on insns with a single
set which contains auto-inc-dec side-effects in the SET_SRC and the majority thinks that
it should be valid. So, this patch fixes the combiner to punt in that case, because otherwise
the auto-inc-dec side-effects from the SET_SRC are lost.
2020-05-06 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/94873
* combine.c (combine_instructions): Don't optimize using REG_EQUAL
note if SET_SRC (set) has side-effects.
* gcc.dg/pr94873.c: New test.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/combine.c | 1 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/pr94873.c | 27 |
4 files changed, 39 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 94f3c25..8040d0d 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2020-05-06 Jakub Jelinek <jakub@redhat.com> + + PR rtl-optimization/94873 + * combine.c (combine_instructions): Don't optimize using REG_EQUAL + note if SET_SRC (set) has side-effects. + 2020-05-06 Hongtao Liu <hongtao.liu@intel.com> Wei Xiao <wei3.xiao@intel.com> diff --git a/gcc/combine.c b/gcc/combine.c index 4c324f3..f69413a 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -1485,6 +1485,7 @@ combine_instructions (rtx_insn *f, unsigned int nregs) if ((set = single_set (temp)) != 0 && (note = find_reg_equal_equiv_note (temp)) != 0 && (note = XEXP (note, 0), GET_CODE (note)) != EXPR_LIST + && ! side_effects_p (SET_SRC (set)) /* Avoid using a register that may already been marked dead by an earlier instruction. */ && ! unmentioned_reg_p (note, SET_SRC (set)) diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index f8e9f2d..1f01ff0 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2020-05-06 Jakub Jelinek <jakub@redhat.com> + + PR rtl-optimization/94873 + * gcc.dg/pr94873.c: New test. + 2020-05-06 Hongtao.liu <hongtao.liu@intel.com> Wei Xiao <wei3.xiao@intel.com> diff --git a/gcc/testsuite/gcc.dg/pr94873.c b/gcc/testsuite/gcc.dg/pr94873.c new file mode 100644 index 0000000..3615217 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr94873.c @@ -0,0 +1,27 @@ +/* PR rtl-optimization/94873 */ +/* { dg-do run { target int128 } } */ +/* { dg-options "-O -fno-merge-constants -fno-split-wide-types -fno-tree-fre" } */ + +__attribute__((noipa)) void +foo (const char *p, int q) +{ + if (p[0] != '%' || p[1] != '0' || p[2] != '2' || p[3] != 'x' || p[4] != '\0') + __builtin_abort (); +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + if ((unsigned char) q != 0x95) + __builtin_abort (); +#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ + if ((unsigned char) q != 0) + __builtin_abort (); +#endif +} + +int +main () +{ + union U { __int128 a; char b[sizeof (__int128)]; }; + char x = ((union U){ .a = 0xF4409395252B9560ULL}).b[1]; + for (unsigned i = 0; i < sizeof (x); i++) + foo ("%02x", i[(volatile unsigned char *) &x]); + return 0; +} |