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| author | Jakub Jelinek <jakub@redhat.com> | 2016-03-29 20:49:00 +0200 |
|---|---|---|
| committer | Jakub Jelinek <jakub@gcc.gnu.org> | 2016-03-29 20:49:00 +0200 |
| commit | a362f023e538bc30dd9f2107f71c2435f62b9289 (patch) | |
| tree | 403c3e385daa0141fced2cc170fd23bc95606ee5 /gcc | |
| parent | e0bffbbb5936be8b6a35d868db4226ca1b2365fa (diff) | |
| download | gcc-a362f023e538bc30dd9f2107f71c2435f62b9289.zip gcc-a362f023e538bc30dd9f2107f71c2435f62b9289.tar.gz gcc-a362f023e538bc30dd9f2107f71c2435f62b9289.tar.bz2 | |
re PR rtl-optimization/70429 (Wrong code with -O1.)
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.
From-SVN: r234531
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/combine.c | 5 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 3 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.c-torture/execute/pr70429.c | 17 |
4 files changed, 30 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index cb62977..0427578 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,10 @@ 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. + PR c++/70353 * tree-inline.c (remap_decls): Don't add_local_decl if cfun is null. diff --git a/gcc/combine.c b/gcc/combine.c index f701f28..1d0e8be 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -10533,6 +10533,11 @@ simplify_shift_const_1 (enum rtx_code code, 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 912a830..2459a2a 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,5 +1,8 @@ 2016-03-29 Jakub Jelinek <jakub@redhat.com> + PR rtl-optimization/70429 + * gcc.c-torture/execute/pr70429.c: New test. + PR tree-optimization/70405 * gcc.dg/pr70405.c: New test. 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 0000000..6b08c8e --- /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; +} |