diff options
| author | Jakub Jelinek <jakub@redhat.com> | 2016-07-07 21:50:41 +0000 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2016-07-07 21:50:41 +0000 |
| commit | 416999907ca65cfdfbfade81f0d2ea8fc6d9bfe6 (patch) | |
| tree | 999adb1f82fc4f0389b011a8227b34e8c815a02c | |
| parent | 432497ce8c7204a1d9c917b61acee1eb7ab0ddf9 (diff) | |
Backported from mainline
2016-03-29 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/70429
* combine.c (simplify_shift_const_1): For ASHIFTRT don't optimize
(cst1 >> count) >> cst2 into (cst1 >> cst2) >> count if
mode != result_mode.
* gcc.c-torture/execute/pr70429.c: New test.
git-svn-id: https://gcc.gnu.org/svn/gcc/branches/gcc-4_9-branch@238141 138bc75d-0d04-0410-961f-82ee72b054a4
| -rw-r--r-- | gcc/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/combine.c | 5 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.c-torture/execute/pr70429.c | 17 |
4 files changed, 34 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 52b69c8f3ea..1dbd3df3062 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,6 +1,13 @@ 2016-07-07 Jakub Jelinek <jakub@redhat.com> Backported from mainline + 2016-03-29 Jakub Jelinek <jakub@redhat.com> + + PR rtl-optimization/70429 + * combine.c (simplify_shift_const_1): For ASHIFTRT don't optimize + (cst1 >> count) >> cst2 into (cst1 >> cst2) >> count if + mode != result_mode. + 2016-03-15 Jakub Jelinek <jakub@redhat.com> PR rtl-optimization/70222 diff --git a/gcc/combine.c b/gcc/combine.c index c48d9b11e47..d2f00d1b7e7 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -10182,6 +10182,11 @@ simplify_shift_const_1 (enum rtx_code code, enum machine_mode result_mode, >> orig_count, result_mode, &complement_p)) break; + /* For ((int) (cstLL >> count)) >> cst2 just give up. Queuing + up outer sign extension (often left and right shift) is + hardly more efficient than the original. See PR70429. */ + if (code == ASHIFTRT && mode != result_mode) + break; rtx new_rtx = simplify_const_binary_operation (code, mode, XEXP (varop, 0), diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index dac1b34b1b3..888311c89cf 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,6 +1,11 @@ 2016-07-07 Jakub Jelinek <jakub@redhat.com> Backported from mainline + 2016-03-29 Jakub Jelinek <jakub@redhat.com> + + PR rtl-optimization/70429 + * gcc.c-torture/execute/pr70429.c: New test. + 2016-03-15 Jakub Jelinek <jakub@redhat.com> PR rtl-optimization/70222 diff --git a/gcc/testsuite/gcc.c-torture/execute/pr70429.c b/gcc/testsuite/gcc.c-torture/execute/pr70429.c new file mode 100644 index 00000000000..6b08c8ead08 --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/execute/pr70429.c @@ -0,0 +1,17 @@ +/* PR rtl-optimization/70429 */ + +__attribute__((noinline, noclone)) int +foo (int a) +{ + return (int) (0x14ff6e2207db5d1fLL >> a) >> 4; +} + +int +main () +{ + if (sizeof (int) != 4 || sizeof (long long) != 8 || __CHAR_BIT__ != 8) + return 0; + if (foo (1) != 0x3edae8 || foo (2) != -132158092) + __builtin_abort (); + return 0; +} |