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?
Thanks,
Kyrill
[1] https://gcc.gnu.org/ml/gcc-patches/2018-02/msg00443.html
2018-02-07 Kyrylo Tkachov <kyrylo.tkac...@arm.com>
PR target/84164
* config/i386/i386.md (*cmpqi_ext_1): Rename to...
(*cmpqi<mode>_ext_1): ... This. Use SWI248 mode iterator
for zero_extract.
(*cmpqi_ext_2): Rename to...
(*cmpqi<mode>_ext_2): ... This. Use SWI248 mode iterator
for zero_extract.
(*cmpqi_ext_3): Rename to...
(*cmpqi<mode>_ext_3): ... This. Use SWI248 mode iterator
for zero_extract.
(*cmpqi_ext_4): Rename to...
(*cmpqi<mode>_ext_4): ... This. Use SWI248 mode iterator
for zero_extract.
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index a4832bf696f321e8ee5aad71fa946ca198d9d689..ced9a3e823ae6c4586be510a782d354f4d364daa 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)))]
