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Re: [PATCH][i386][3/3] PR target/84164: Make *cmpqi_ext_<n> patterns accept more zero_extract modes
On 15/02/18 07:25, Uros Bizjak wrote:
On Wed, Feb 14, 2018 at 7:04 PM, Kyrill Tkachov
<kyrylo.tkachov@foss.arm.com> wrote:
On 13/02/18 16:45, Jeff Law wrote:
On 02/09/2018 07:50 AM, Kyrill Tkachov wrote:
Hi Uros,
On 08/02/18 22:54, Uros Bizjak wrote:
On Thu, Feb 8, 2018 at 6:11 PM, Kyrill Tkachov
<kyrylo.tkachov@foss.arm.com> wrote:
Hi all,
This patch fixes some fallout in the i386 testsuite that occurs after
the
simplification in patch [1/3] [1].
The gcc.target/i386/extract-2.c FAILs because it expects to match:
(set (reg:CC 17 flags)
(compare:CC (subreg:QI (zero_extract:SI (reg:HI 98)
(const_int 8 [0x8])
(const_int 8 [0x8])) 0)
(const_int 4 [0x4])))
which is the *cmpqi_ext_2 pattern in i386.md but with the new
simplification
the combine/simplify-rtx
machinery produces:
(set (reg:CC 17 flags)
(compare:CC (subreg:QI (zero_extract:HI (reg:HI 98)
(const_int 8 [0x8])
(const_int 8 [0x8])) 0)
(const_int 4 [0x4])))
Notice that the zero_extract now has HImode like the register source
rather
than SImode.
The existing *cmpqi_ext_<n> patterns however explicitly demand an
SImode on
the zero_extract.
I'm not overly familiar with the i386 port but I think that's too
restrictive.
The RTL documentation says:
For (zero_extract:m loc size pos) "The mode m is the same as the mode
that
would be used for loc if it were a register."
I'm not sure if that means that the mode of the zero_extract and the
source
register must always match (as is the
case after patch [1/3]) but in any case it shouldn't matter
semantically
since we're taking a QImode subreg of the whole
thing anyway.
So the proposed solution in this patch is to allow HI, SI and DImode
zero_extracts in these patterns as these are the
modes that the ext_register_operand predicate accepts, so that the
patterns
can match the new form above.
With this patch the aforementioned test passes again and bootstrap and
testing on x86_64-unknown-linux-gnu shows
no regressions.
Is this ok for trunk if the first patch is accepted?
Huh, there are many other zero-extract patterns besides cmpqi_ext_*
with QImode subreg of SImode zero_extract in i386.md, used to access
high QImode register of HImode pair. A quick grep shows these that
have _ext_ in their name:
(define_insn "*cmpqi_ext_1"
(define_insn "*cmpqi_ext_2"
(define_expand "cmpqi_ext_3"
(define_insn "*cmpqi_ext_3"
(define_insn "*cmpqi_ext_4"
(define_insn "addqi_ext_1"
(define_insn "*addqi_ext_2"
(define_expand "testqi_ext_1_ccno"
(define_insn "*testqi_ext_1"
(define_insn "*testqi_ext_2"
(define_insn_and_split "*testqi_ext_3"
(define_insn "andqi_ext_1"
(define_insn "*andqi_ext_1_cc"
(define_insn "*andqi_ext_2"
(define_insn "*<code>qi_ext_1"
(define_insn "*<code>qi_ext_2"
(define_expand "xorqi_ext_1_cc"
(define_insn "*xorqi_ext_1_cc"
There are also relevant splitters and peephole2 patterns.
I see. Another approach I've looked at is removing the mode specifier
from
the zero_extract in these patterns. This means that they can be of any
mode
so they will match all of these modes without creating new patterns
through
iterators. That also works for the testcase and passes bootstrap and
testing
however there is the snag that the define_insns that don't start with a
"*"
are used to generate RTL through the gen_* mechanism and in that context
the absence of a mode on the zero_extract would mean a VOIDmode
zero_extract
would be created, which I'm fairly sure is not good. So in my
experiments I left
those patterns alone (with an explicit SI on the zero_extract).
IIRC, SImode zero_extract was enough to catch all high-register uses.
There will be a pattern explosion if we want to handle all other
integer modes here. However, I'm not a RTL expert, so someone will
have to say what is the correct RTX form here.
Jeff, Richard, could you please give us some guidance on this issue?
Sorry for the trouble.
I don't think any of the patterns above are known to the generic code.
So you just have to check the x86 backend to see their precise uses in a
generator (ie gen_cmpqi_ext_3) and verify those do not allow a VOIDmode
(or any other undesirable mode) to slip through.
Jeff
Thanks Jeff, I did have a look. I think we want to maintain the SImode on
the
RTL that gets created through these named expanders, as generating a
VOIDmode
zero_extract is not valid. So my patch leaves those intact.
The patch removes the mode from the zero_extract RTXes in patterns that are
only ever going to get matched (as opposed to generated). That is the ones
that
start with "*" in their name.
This should allow them to match any of the zero_extract modes that
might get generated by the midend.
Bootstrapped and tested on x86_64-unknown-linux-gnu.
Is this a preferable approach?
We are trying to avoid VOIDmode RTXes as much as possible (to tighten
pattern matching to avoid various surpsrises). Looking at these
instructions, I think that using SWI248 in insn and peephole2 patterns
should be OK.
So, if it survives regression tests, the patch is OK with SWI248 mode
instead of void mode.
Thanks,
Uros.
Thanks Uros, here's my proposed patch.
If we're adding the mode iterator we also have to adjust the name of the patterns I believe,
so this patch does that too.
Bootstrapped and tested on x86_64-unknown-linux-gnu.
I will commit it if the prerequisite patch at https://gcc.gnu.org/ml/gcc-patches/2018-02/msg00443.html
is approved.
Thank you for your guidance,
Kyrill
2018-02-16 Kyrylo Tkachov <kyrylo.tkachov@arm.com>
PR target/84164
* config/i386/i386.md (*cmpqi_ext_1): Rename to...
(*cmpqi<mode>_ext_1): ... This. Use SWI248 for zero_extract mode.
(*cmpqi<mode>_ext_2): Rename to...
(*cmpqi_ext_2): ... This. Use SWI248 for zero_extract mode.
(*cmpqi_ext_3): Rename to...
(*cmpqi<mode>_ext_3): ... This. Use SWI248 for zero_extract mode.
(*cmpqi_ext_4): Rename to...
(*cmpqi<mode>_ext_4): ... This. Use SWI248 for zero_extract mode.
(*extzvqi_mem_rex64): Rename to...
(*extzvqi<mode>_mem_rex64): ... This. Use SWI248 for zero_extract
mode.
(*extzvqi): Rename to..
(*extzvqi<mode>): ... This. Use SWI248 for zero_extract mode.
(QImode zero_extract peephole): Use SWI248 for zero_extract mode.
(*addqi_ext_2): Rename to...
(*addqi<mode>_ext_2): ... This. Use SWI248 for zero_extract mode.
(*testqi_ext_1): Rename to...
(*testqi<mode>_ext_1): ... This. Use SWI248 for zero_extract mode.
(*testqi_ext_2): Rename to...
(*testqi<mode>_ext_2): ... This. Use SWI248 for zero_extract mode.
(*andqi_ext_1_cc): Rename to...
(*andqi<mode>_ext_1_cc): ... This. Use SWI248 for zero_extract mode.
(*andqi_ext_2): Rename to...
(*andqi<mode>_ext_2): ... This. Use SWI248 for zero_extract mode.
(*<code>qi_ext_1): Rename to...
(*<code>qi<mode>_ext_1): ... This. Use SWI248 for zero_extract mode.
(*<code>qi_ext_2): Rename to...
(*<code>qi<mode>_ext_2): ... This. Use SWI248 for zero_extract mode.
(*xorqi_ext_1_cc): Rename to...
(*xorqi<mode>_ext_1_cc): ... This. Use SWI248 for zero_extract mode.
(AND QImode subreg of zero_extract peephole): Use SWI248 for
zero_extract mode.
commit 864d03bba8274e1281142e389961b499d6cbf81b
Author: Kyrylo Tkachov <kyrylo.tkachov@arm.com>
Date: Wed Feb 7 15:46:48 2018 +0000
[i386] Make QImode subregs of zero_extracts more robust
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 3998053..c5a7d88 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -1328,12 +1328,12 @@ (define_insn "*cmp<mode>_minus_1"
[(set_attr "type" "icmp")
(set_attr "mode" "<MODE>")])
-(define_insn "*cmpqi_ext_1"
+(define_insn "*cmpqi<mode>_ext_1"
[(set (reg FLAGS_REG)
(compare
(match_operand:QI 0 "nonimmediate_operand" "QBc,m")
(subreg:QI
- (zero_extract:SI
+ (zero_extract:SWI248
(match_operand 1 "ext_register_operand" "Q,Q")
(const_int 8)
(const_int 8)) 0)))]
@@ -1343,11 +1343,11 @@ (define_insn "*cmpqi_ext_1"
(set_attr "type" "icmp")
(set_attr "mode" "QI")])
-(define_insn "*cmpqi_ext_2"
+(define_insn "*cmpqi<mode>_ext_2"
[(set (reg FLAGS_REG)
(compare
(subreg:QI
- (zero_extract:SI
+ (zero_extract:SWI248
(match_operand 0 "ext_register_operand" "Q")
(const_int 8)
(const_int 8)) 0)
@@ -1368,11 +1368,11 @@ (define_expand "cmpqi_ext_3"
(const_int 8)) 0)
(match_operand:QI 1 "const_int_operand")))])
-(define_insn "*cmpqi_ext_3"
+(define_insn "*cmpqi<mode>_ext_3"
[(set (reg FLAGS_REG)
(compare
(subreg:QI
- (zero_extract:SI
+ (zero_extract:SWI248
(match_operand 0 "ext_register_operand" "Q,Q")
(const_int 8)
(const_int 8)) 0)
@@ -1383,16 +1383,16 @@ (define_insn "*cmpqi_ext_3"
(set_attr "type" "icmp")
(set_attr "mode" "QI")])
-(define_insn "*cmpqi_ext_4"
+(define_insn "*cmpqi<mode>_ext_4"
[(set (reg FLAGS_REG)
(compare
(subreg:QI
- (zero_extract:SI
+ (zero_extract:SWI248
(match_operand 0 "ext_register_operand" "Q")
(const_int 8)
(const_int 8)) 0)
(subreg:QI
- (zero_extract:SI
+ (zero_extract:SWI248
(match_operand 1 "ext_register_operand" "Q")
(const_int 8)
(const_int 8)) 0)))]
@@ -2928,10 +2928,10 @@ (define_expand "extzv<mode>"
operands[1] = copy_to_reg (operands[1]);
})
-(define_insn "*extzvqi_mem_rex64"
+(define_insn "*extzvqi<mode>_mem_rex64"
[(set (match_operand:QI 0 "norex_memory_operand" "=Bn")
(subreg:QI
- (zero_extract:SI (match_operand 1 "ext_register_operand" "Q")
+ (zero_extract:SWI248 (match_operand 1 "ext_register_operand" "Q")
(const_int 8)
(const_int 8)) 0))]
"TARGET_64BIT && reload_completed"
@@ -2949,10 +2949,10 @@ (define_insn "*extzv<mode>"
[(set_attr "type" "imovx")
(set_attr "mode" "SI")])
-(define_insn "*extzvqi"
+(define_insn "*extzvqi<mode>"
[(set (match_operand:QI 0 "nonimmediate_operand" "=QBc,?R,m")
(subreg:QI
- (zero_extract:SI (match_operand 1 "ext_register_operand" "Q,Q,Q")
+ (zero_extract:SWI248 (match_operand 1 "ext_register_operand" "Q,Q,Q")
(const_int 8)
(const_int 8)) 0))]
""
@@ -2980,7 +2980,7 @@ (define_insn "*extzvqi"
(define_peephole2
[(set (match_operand:QI 0 "register_operand")
(subreg:QI
- (zero_extract:SI (match_operand 1 "ext_register_operand")
+ (zero_extract:SWI248 (match_operand 1 "ext_register_operand")
(const_int 8)
(const_int 8)) 0))
(set (match_operand:QI 2 "norex_memory_operand") (match_dup 0))]
@@ -6340,18 +6340,18 @@ (define_insn "addqi_ext_1"
(const_string "alu")))
(set_attr "mode" "QI")])
-(define_insn "*addqi_ext_2"
+(define_insn "*addqi<mode>_ext_2"
[(set (zero_extract:SI (match_operand 0 "ext_register_operand" "+Q")
(const_int 8)
(const_int 8))
(subreg:SI
(plus:QI
(subreg:QI
- (zero_extract:SI (match_operand 1 "ext_register_operand" "%0")
+ (zero_extract:SWI248 (match_operand 1 "ext_register_operand" "%0")
(const_int 8)
(const_int 8)) 0)
(subreg:QI
- (zero_extract:SI (match_operand 2 "ext_register_operand" "Q")
+ (zero_extract:SWI248 (match_operand 2 "ext_register_operand" "Q")
(const_int 8)
(const_int 8)) 0)) 0))
(clobber (reg:CC FLAGS_REG))]
@@ -8596,12 +8596,12 @@ (define_expand "testqi_ext_1_ccno"
(match_operand 1 "const_int_operand"))
(const_int 0)))])
-(define_insn "*testqi_ext_1"
+(define_insn "*testqi<mode>_ext_1"
[(set (reg FLAGS_REG)
(compare
(and:QI
(subreg:QI
- (zero_extract:SI (match_operand 0 "ext_register_operand" "Q,Q")
+ (zero_extract:SWI248 (match_operand 0 "ext_register_operand" "Q,Q")
(const_int 8)
(const_int 8)) 0)
(match_operand:QI 1 "general_operand" "QnBc,m"))
@@ -8612,16 +8612,16 @@ (define_insn "*testqi_ext_1"
(set_attr "type" "test")
(set_attr "mode" "QI")])
-(define_insn "*testqi_ext_2"
+(define_insn "*testqi<mode>_ext_2"
[(set (reg FLAGS_REG)
(compare
(and:QI
(subreg:QI
- (zero_extract:SI (match_operand 0 "ext_register_operand" "Q")
+ (zero_extract:SWI248 (match_operand 0 "ext_register_operand" "Q")
(const_int 8)
(const_int 8)) 0)
(subreg:QI
- (zero_extract:SI (match_operand 1 "ext_register_operand" "Q")
+ (zero_extract:SWI248 (match_operand 1 "ext_register_operand" "Q")
(const_int 8)
(const_int 8)) 0))
(const_int 0)))]
@@ -9147,12 +9147,12 @@ (define_insn "andqi_ext_1"
;; Generated by peephole translating test to and. This shows up
;; often in fp comparisons.
-(define_insn "*andqi_ext_1_cc"
+(define_insn "*andqi<mode>_ext_1_cc"
[(set (reg FLAGS_REG)
(compare
(and:QI
(subreg:QI
- (zero_extract:SI (match_operand 1 "ext_register_operand" "0,0")
+ (zero_extract:SWI248 (match_operand 1 "ext_register_operand" "0,0")
(const_int 8)
(const_int 8)) 0)
(match_operand:QI 2 "general_operand" "QnBc,m"))
@@ -9163,7 +9163,7 @@ (define_insn "*andqi_ext_1_cc"
(subreg:SI
(and:QI
(subreg:QI
- (zero_extract:SI (match_dup 1)
+ (zero_extract:SWI248 (match_dup 1)
(const_int 8)
(const_int 8)) 0)
(match_dup 2)) 0))]
@@ -9175,18 +9175,18 @@ (define_insn "*andqi_ext_1_cc"
(set_attr "type" "alu")
(set_attr "mode" "QI")])
-(define_insn "*andqi_ext_2"
+(define_insn "*andqi<mode>_ext_2"
[(set (zero_extract:SI (match_operand 0 "ext_register_operand" "+Q")
(const_int 8)
(const_int 8))
(subreg:SI
(and:QI
(subreg:QI
- (zero_extract:SI (match_operand 1 "ext_register_operand" "%0")
+ (zero_extract:SWI248 (match_operand 1 "ext_register_operand" "%0")
(const_int 8)
(const_int 8)) 0)
(subreg:QI
- (zero_extract:SI (match_operand 2 "ext_register_operand" "Q")
+ (zero_extract:SWI248 (match_operand 2 "ext_register_operand" "Q")
(const_int 8)
(const_int 8)) 0)) 0))
(clobber (reg:CC FLAGS_REG))]
@@ -9564,14 +9564,14 @@ (define_insn "*<code><mode>_3"
[(set_attr "type" "alu")
(set_attr "mode" "<MODE>")])
-(define_insn "*<code>qi_ext_1"
+(define_insn "*<code>qi<mode>_ext_1"
[(set (zero_extract:SI (match_operand 0 "ext_register_operand" "+Q,Q")
(const_int 8)
(const_int 8))
(subreg:SI
(any_or:QI
(subreg:QI
- (zero_extract:SI (match_operand 1 "ext_register_operand" "0,0")
+ (zero_extract:SWI248 (match_operand 1 "ext_register_operand" "0,0")
(const_int 8)
(const_int 8)) 0)
(match_operand:QI 2 "general_operand" "QnBc,m")) 0))
@@ -9584,18 +9584,18 @@ (define_insn "*<code>qi_ext_1"
(set_attr "type" "alu")
(set_attr "mode" "QI")])
-(define_insn "*<code>qi_ext_2"
+(define_insn "*<code>qi<mode>_ext_2"
[(set (zero_extract:SI (match_operand 0 "ext_register_operand" "+Q")
(const_int 8)
(const_int 8))
(subreg:SI
(any_or:QI
(subreg:QI
- (zero_extract:SI (match_operand 1 "ext_register_operand" "%0")
+ (zero_extract:SWI248 (match_operand 1 "ext_register_operand" "%0")
(const_int 8)
(const_int 8)) 0)
(subreg:QI
- (zero_extract:SI (match_operand 2 "ext_register_operand" "Q")
+ (zero_extract:SWI248 (match_operand 2 "ext_register_operand" "Q")
(const_int 8)
(const_int 8)) 0)) 0))
(clobber (reg:CC FLAGS_REG))]
@@ -9681,12 +9681,12 @@ (define_expand "xorqi_ext_1_cc"
(const_int 8)) 0)
(match_dup 2)) 0))])])
-(define_insn "*xorqi_ext_1_cc"
+(define_insn "*xorqi<mode>_ext_1_cc"
[(set (reg FLAGS_REG)
(compare
(xor:QI
(subreg:QI
- (zero_extract:SI (match_operand 1 "ext_register_operand" "0,0")
+ (zero_extract:SWI248 (match_operand 1 "ext_register_operand" "0,0")
(const_int 8)
(const_int 8)) 0)
(match_operand:QI 2 "general_operand" "QnBc,m"))
@@ -9697,7 +9697,7 @@ (define_insn "*xorqi_ext_1_cc"
(subreg:SI
(xor:QI
(subreg:QI
- (zero_extract:SI (match_dup 1)
+ (zero_extract:SWI248 (match_dup 1)
(const_int 8)
(const_int 8)) 0)
(match_dup 2)) 0))]
@@ -18800,7 +18800,7 @@ (define_peephole2
(match_operator 1 "compare_operator"
[(and:QI
(subreg:QI
- (zero_extract:SI (match_operand 2 "QIreg_operand")
+ (zero_extract:SWI248 (match_operand 2 "QIreg_operand")
(const_int 8)
(const_int 8)) 0)
(match_operand 3 "const_int_operand"))
@@ -18814,7 +18814,7 @@ (define_peephole2
(match_op_dup 1
[(and:QI
(subreg:QI
- (zero_extract:SI (match_dup 2)
+ (zero_extract:SWI248 (match_dup 2)
(const_int 8)
(const_int 8)) 0)
(match_dup 3))
@@ -18825,7 +18825,7 @@ (define_peephole2
(subreg:SI
(and:QI
(subreg:QI
- (zero_extract:SI (match_dup 2)
+ (zero_extract:SWI248 (match_dup 2)
(const_int 8)
(const_int 8)) 0)
(match_dup 3)) 0))])])