diff options
| author | Eric Botcazou <ebotcazou@adacore.com> | 2021-09-17 10:12:12 +0200 |
|---|---|---|
| committer | Eric Botcazou <ebotcazou@adacore.com> | 2021-09-17 10:15:38 +0200 |
| commit | 687e30d9d74f5c69a54617147ce3433b07ee59ce (patch) | |
| tree | 601e54497c9b1a73c55e40eaf0bb007b196addb8 /gcc/combine.c | |
| parent | a5873aadb6dd749558924eba3e1b4c21755721ba (diff) | |
| download | gcc-687e30d9d74f5c69a54617147ce3433b07ee59ce.zip gcc-687e30d9d74f5c69a54617147ce3433b07ee59ce.tar.gz gcc-687e30d9d74f5c69a54617147ce3433b07ee59ce.tar.bz2 | |
Fix PR rtl-optimization/102306
This is a duplication of volatile loads introduced during GCC 9 development
by the 2->2 mechanism of the RTL combiner. There is already a substantial
checking for volatile references in can_combine_p but it implicitly assumes
that the combination reduces the number of instructions, which is of course
not the case here. So the fix teaches try_combine to abort the combination
when it is about to make a copy of volatile references to preserve them.
gcc/
PR rtl-optimization/102306
* combine.c (try_combine): Abort the combination if we are about to
duplicate volatile references.
gcc/testsuite/
* gcc.target/sparc/20210917-1.c: New test.
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index 290a366..892c834 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -3063,6 +3063,16 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, return 0; } + /* We cannot safely duplicate volatile references in any case. */ + + if ((added_sets_2 && volatile_refs_p (PATTERN (i2))) + || (added_sets_1 && volatile_refs_p (PATTERN (i1))) + || (added_sets_0 && volatile_refs_p (PATTERN (i0)))) + { + undo_all (); + return 0; + } + /* Count how many auto_inc expressions there were in the original insns; we need to have the same number in the resulting patterns. */ |