On Mon, Nov 15, 2021 at 11:14 AM Jeff Law <jeffreya...@gmail.com> wrote:
>
>
>
> On 11/15/2021 12:05 PM, H.J. Lu wrote:
> > On Mon, Nov 15, 2021 at 10:59 AM Jeff Law <jeffreya...@gmail.com> wrote:
> >>
> >>
> >> On 11/15/2021 6:39 AM, H.J. Lu via Gcc-patches wrote:
> >>> Check optab before transforming equivalent, but slighly different cases
> >>> of atomic bit test and operations to their canonical forms.
> >>>
> >>> gcc/
> >>>
> >>> PR middle-end/103184
> >>> * tree-ssa-ccp.c (optimize_atomic_bit_test_and): Check optab
> >>> before transforming equivalent, but slighly different cases to
> >>> their canonical forms.
> >>>
> >>> gcc/testsuite/
> >>>
> >>> PR middle-end/103184
> >>> * gcc.dg/pr103184-1.c: New test.
> >>> * gcc.dg/pr103184-2.c: Likewise.
> >>> }
> >>> }
> >>>
> >>> - switch (fn)
> >>> - {
> >>> - case IFN_ATOMIC_BIT_TEST_AND_SET:
> >>> - optab = atomic_bit_test_and_set_optab;
> >>> - break;
> >>> - case IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT:
> >>> - optab = atomic_bit_test_and_complement_optab;
> >>> - break;
> >>> - case IFN_ATOMIC_BIT_TEST_AND_RESET:
> >>> - optab = atomic_bit_test_and_reset_optab;
> >>> - break;
> >>> - default:
> >>> - return;
> >>> - }
> >>> -
> >>> if (optab_handler (optab, TYPE_MODE (TREE_TYPE (lhs))) ==
> >>> CODE_FOR_nothing)
> >>> return;
> >> Shouldn't the test of the return value of optab_handler here just go
> >> away since we're testing it earlier? OK with that fix.
> >>
> > The earlier check is predicated on if (rhs_code != BIT_AND_EXPR):
> >
> > if (rhs_code != BIT_AND_EXPR)
> > {
> > if (rhs_code != NOP_EXPR && rhs_code != BIT_NOT_EXPR)
> > return;
> >
> > tree use_lhs = gimple_assign_lhs (use_stmt);
> > if (TREE_CODE (use_lhs) == SSA_NAME
> > && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (use_lhs))
> > return;
> >
> > tree use_rhs = gimple_assign_rhs1 (use_stmt);
> > if (lhs != use_rhs)
> > return;
> >
> > if (optab_handler (optab, TYPE_MODE (TREE_TYPE (lhs)))
> > == CODE_FOR_nothing)
> > return;
> >
> > I can add an "else"
> >
> > else if (optab_handler (optab, TYPE_MODE (TREE_TYPE (lhs)))
> > == CODE_FOR_nothing)
> > return;
> >
> > Will it be OK?
> Sure. THanks.
> jeff
This is the patch I am checking in.
Thanks.
--
H.J.
From 357d8a03b7ee32a29a78ac9be5711e6b0cd99cc4 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Fri, 12 Nov 2021 07:21:43 -0800
Subject: [PATCH v2] Check optab before transforming atomic bit test and
operations
Check optab before transforming equivalent, but slighly different cases
of atomic bit test and operations to their canonical forms.
gcc/
PR middle-end/103184
* tree-ssa-ccp.c (optimize_atomic_bit_test_and): Check optab
before transforming equivalent, but slighly different cases to
their canonical forms.
gcc/testsuite/
PR middle-end/103184
* gcc.dg/pr103184-1.c: New test.
* gcc.dg/pr103184-2.c: Likewise.
---
gcc/testsuite/gcc.dg/pr103184-1.c | 43 +++++++++++++++++++++++++++++++
gcc/testsuite/gcc.dg/pr103184-2.c | 12 +++++++++
gcc/tree-ssa-ccp.c | 38 +++++++++++++++------------
3 files changed, 76 insertions(+), 17 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/pr103184-1.c
create mode 100644 gcc/testsuite/gcc.dg/pr103184-2.c
diff --git a/gcc/testsuite/gcc.dg/pr103184-1.c b/gcc/testsuite/gcc.dg/pr103184-1.c
new file mode 100644
index 00000000000..e567f95f63f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr103184-1.c
@@ -0,0 +1,43 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+extern char foo;
+extern unsigned char bar;
+
+int
+foo1 (void)
+{
+ return __sync_fetch_and_and (&foo, ~1) & 1;
+}
+
+int
+foo2 (void)
+{
+ return __sync_fetch_and_or (&foo, 1) & 1;
+}
+
+int
+foo3 (void)
+{
+ return __sync_fetch_and_xor (&foo, 1) & 1;
+}
+
+unsigned short
+bar1 (void)
+{
+ return __sync_fetch_and_and (&bar, ~1) & 1;
+}
+
+unsigned short
+bar2 (void)
+{
+ return __sync_fetch_and_or (&bar, 1) & 1;
+}
+
+unsigned short
+bar3 (void)
+{
+ return __sync_fetch_and_xor (&bar, 1) & 1;
+}
+
+/* { dg-final { scan-assembler-times "lock;?\[ \t\]*cmpxchgb" 6 { target { x86_64-*-* i?86-*-* } } } } */
diff --git a/gcc/testsuite/gcc.dg/pr103184-2.c b/gcc/testsuite/gcc.dg/pr103184-2.c
new file mode 100644
index 00000000000..499761fdbfd
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr103184-2.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+#include <stdatomic.h>
+
+int
+tbit0 (_Atomic int* a, int n)
+{
+#define BIT (0x1 << n)
+ return atomic_fetch_or (a, BIT) & BIT;
+#undef BIT
+}
diff --git a/gcc/tree-ssa-ccp.c b/gcc/tree-ssa-ccp.c
index 0f79e9f05bd..0666dc652d0 100644
--- a/gcc/tree-ssa-ccp.c
+++ b/gcc/tree-ssa-ccp.c
@@ -3366,6 +3366,21 @@ optimize_atomic_bit_test_and (gimple_stmt_iterator *gsip,
|| !gimple_vdef (call))
return;
+ switch (fn)
+ {
+ case IFN_ATOMIC_BIT_TEST_AND_SET:
+ optab = atomic_bit_test_and_set_optab;
+ break;
+ case IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT:
+ optab = atomic_bit_test_and_complement_optab;
+ break;
+ case IFN_ATOMIC_BIT_TEST_AND_RESET:
+ optab = atomic_bit_test_and_reset_optab;
+ break;
+ default:
+ return;
+ }
+
tree bit = nullptr;
mask = gimple_call_arg (call, 1);
@@ -3384,6 +3399,10 @@ optimize_atomic_bit_test_and (gimple_stmt_iterator *gsip,
if (lhs != use_rhs)
return;
+ if (optab_handler (optab, TYPE_MODE (TREE_TYPE (lhs)))
+ == CODE_FOR_nothing)
+ return;
+
gimple *g;
gimple_stmt_iterator gsi;
tree var;
@@ -3627,23 +3646,8 @@ optimize_atomic_bit_test_and (gimple_stmt_iterator *gsip,
bit = build_int_cst (TREE_TYPE (lhs), ibit);
}
}
-
- switch (fn)
- {
- case IFN_ATOMIC_BIT_TEST_AND_SET:
- optab = atomic_bit_test_and_set_optab;
- break;
- case IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT:
- optab = atomic_bit_test_and_complement_optab;
- break;
- case IFN_ATOMIC_BIT_TEST_AND_RESET:
- optab = atomic_bit_test_and_reset_optab;
- break;
- default:
- return;
- }
-
- if (optab_handler (optab, TYPE_MODE (TREE_TYPE (lhs))) == CODE_FOR_nothing)
+ else if (optab_handler (optab, TYPE_MODE (TREE_TYPE (lhs)))
+ == CODE_FOR_nothing)
return;
tree use_lhs = gimple_assign_lhs (use_stmt);
--
2.33.1
