On 2015-09-11 4:15 AM, Bernd Schmidt wrote:
On 09/11/2015 01:21 AM, John David Anglin wrote:
As noted in the PR, expand_atomic_compare_and_swap can generate wrong
code when libcalls are emitted
for the sync_compare_and_swap and the result comparison test. This is
fixed by emitting a move insn to copy
the result rtx of the sync_compare_and_swap libcall to target_oval
instead of directly assigning it.
Could you provide relevant parts of the rtl dumps or (preferrably) the
patch you are using to enable the libcall?
This can be duplicated with a cross to hppa-unknown-linux-gnu with the
following change to enable the libcall:
Index: config/pa/pa.c
===================================================================
--- config/pa/pa.c (revision 227689)
+++ config/pa/pa.c (working copy)
@@ -5737,7 +5737,7 @@
}
if (TARGET_SYNC_LIBCALL)
- init_sync_libfuncs (UNITS_PER_WORD);
+ init_sync_libfuncs (8);
}
The relevant rtl from .expand is:
(call_insn 48 47 49 (parallel [
(set (reg:DI 28 %r28)
(call (mem:SI (symbol_ref/v:SI
("@__sync_val_compare_and_swap_8") [flags 0x41]) [0 S4 A32])
(const_int 64 [0x40])))
(clobber (reg:SI 1 %r1))
(clobber (reg:SI 2 %r2))
(use (const_int 0 [0]))
]) xxx.c:6 -1
(expr_list:REG_EH_REGION (const_int -2147483648 [0xffffffff80000000])
(nil))
(expr_list (use (reg:DI 23 %r23))
(expr_list (use (reg:SI 26 %r26))
(expr_list (use (mem:DI (plus:SI (reg/f:SI 93
virtual-outgoing-args)
(const_int -24 [0xffffffffffffffe8])) [0
S8 A64]))
(nil)))))
(insn 49 48 50 (set (reg:SI 128)
(const_int 1 [0x1])) xxx.c:6 -1
(nil))
(insn 50 49 51 (set (reg:DI 23 %r23)
(reg:DI 123)) xxx.c:6 -1
(nil))
(insn 51 50 52 (set (reg:DI 25 %r25)
(reg:DI 28 %r28)) xxx.c:6 -1
(nil))
(call_insn/u 52 51 53 (parallel [
(set (reg:SI 28 %r28)
(call (mem:SI (symbol_ref/v:SI ("@__ucmpdi2") [flags
0x41]) [0 S4 A32])
(const_int 64 [0x40])))
(clobber (reg:SI 1 %r1))
(clobber (reg:SI 2 %r2))
(use (const_int 0 [0]))
]) xxx.c:6 -1
(expr_list:REG_EH_REGION (const_int -2147483648 [0xffffffff80000000])
(nil))
(expr_list (use (reg:DI 23 %r23))
(expr_list (use (reg:DI 25 %r25))
(nil))))
(jump_insn 53 52 54 (set (pc)
(if_then_else (eq (reg:SI 28 %r28)
(const_int 1 [0x1]))
(label_ref 55)
(pc))) xxx.c:6 -1
(nil))
(insn 54 53 55 (set (reg:SI 128)
(const_int 0 [0])) xxx.c:6 -1
(nil))
(code_label 55 54 56 3 "" [0 uses])
(jump_insn 56 55 57 (set (pc)
(if_then_else (ne (reg:SI 128)
(const_int 0 [0]))
(label_ref 58)
(pc))) xxx.c:6 -1
(nil))
(insn 57 56 58 (set (mem:DI (reg:SI 122) [0 S8 A64])
(reg:DI 28 %r28)) xxx.c:6 -1
(nil))
(code_label 58 57 59 4 "" [0 uses])
(insn 59 58 0 (set (reg:SI 102)
(reg:SI 128)) xxx.c:6 -1
(nil))
;; if (_17 != 0)
(jump_insn 60 59 0 (set (pc)
(if_then_else (ne (reg:SI 102)
(const_int 0 [0]))
(label_ref 0)
(pc))) xxx.c:6 -1
(nil))
The value in reg:DI 28 returned by the __sync_val_compare_and_swap_8 is
clobbered by the
the call to __ucmpdi2. It is needed in insn 57.
Dave
--
John David Anglin dave.ang...@bell.net
