Every call to darn should deliver a *new* random number; such calls
shouldnot be CSEd together. So they should be unspec_volatile, not
plain unspec.
Tested on powerpc64-linux {-m32,-m64}. (New testcase coming soon).
Committing to trunk, and will backport to 9, 8, 7 as well.
Segher
2019-08-22 Segher Boessenkool <seg...@kernel.crashing.org>
PR target/91481
* config/rs6000/rs6000.md (unspec): Delete UNSPEC_DARN, UNSPEC_DARN_32,
and UNSPEC_DARN_RAW.
(unspecv): New enumerator values UNSPECV_DARN, UNSPECV_DARN_32, and
UNSPECV_DARN_RAW.
(darn_32): Use an unspec_volatile, and UNSPECV_DARN_32.
(darn_raw): Use an unspec_volatile, and UNSPECV_DARN_RAW.
(darn): Use an unspec_volatile, and UNSPECV_DARN.
---
gcc/config/rs6000/rs6000.md | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index 68cdf68..b0aea23 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -134,9 +134,6 @@ (define_c_enum "unspec"
UNSPEC_LSQ
UNSPEC_FUSION_GPR
UNSPEC_STACK_CHECK
- UNSPEC_DARN
- UNSPEC_DARN_32
- UNSPEC_DARN_RAW
UNSPEC_CMPRB
UNSPEC_CMPRB2
UNSPEC_CMPEQB
@@ -168,6 +165,9 @@ (define_c_enum "unspecv"
UNSPECV_EH_RR ; eh_reg_restore
UNSPECV_ISYNC ; isync instruction
UNSPECV_MFTB ; move from time base
+ UNSPECV_DARN ; darn 1 (deliver a random number)
+ UNSPECV_DARN_32 ; darn 2
+ UNSPECV_DARN_RAW ; darn 0
UNSPECV_NLGR ; non-local goto receiver
UNSPECV_MFFS ; Move from FPSCR
UNSPECV_MFFSL ; Move from FPSCR light instruction version
@@ -14387,21 +14387,21 @@ (define_insn "*cmp<mode>_hw"
(define_insn "darn_32"
[(set (match_operand:SI 0 "register_operand" "=r")
- (unspec:SI [(const_int 0)] UNSPEC_DARN_32))]
+ (unspec_volatile:SI [(const_int 0)] UNSPECV_DARN_32))]
"TARGET_P9_MISC"
"darn %0,0"
[(set_attr "type" "integer")])
(define_insn "darn_raw"
[(set (match_operand:DI 0 "register_operand" "=r")
- (unspec:DI [(const_int 0)] UNSPEC_DARN_RAW))]
+ (unspec_volatile:DI [(const_int 0)] UNSPECV_DARN_RAW))]
"TARGET_P9_MISC && TARGET_64BIT"
"darn %0,2"
[(set_attr "type" "integer")])
(define_insn "darn"
[(set (match_operand:DI 0 "register_operand" "=r")
- (unspec:DI [(const_int 0)] UNSPEC_DARN))]
+ (unspec_volatile:DI [(const_int 0)] UNSPECV_DARN))]
"TARGET_P9_MISC && TARGET_64BIT"
"darn %0,1"
[(set_attr "type" "integer")])
--
1.8.3.1
