https://gcc.gnu.org/g:71f6540fc54036cc8f71db497cc22816f794549a
commit r15-7483-g71f6540fc54036cc8f71db497cc22816f794549a
Author: Jeff Law <j...@ventanamicro.com>
Date: Tue Feb 11 16:55:03 2025 -0700
[PR target/115478] Accept ADD, IOR or XOR when combining objects with no
bits in common
So the change to prefer ADD over IOR for combining two objects with no bits
in
common is (IMHO) generally good. It has some minor fallout.
In particular the aarch64 port (and I suspect others) have patterns that
recognize IOR, but not PLUS or XOR for these cases and thus tests which
expected to optimize with IOR are no longer optimizing.
Roger suggested using a code iterator for this purpose. Richard S.
suggested a
new match operator to cover those cases.
I really like the match operator idea, but as Richard S. notes in the PR it
would require either not validating the "no bits in common", which
dramatically
reduces the utility IMHO or we'd need some work to allow consistent results
without polluting the nonzero bits cache.
So this patch goes back to Roger's idea of just using a match iterator in
the
aarch64 backend (and presumably anywhere else we see this popping up).
Bootstrapped and regression tested on aarch64-linux-gnu where it fixes
bitint-args.c (as expected).
PR target/115478
gcc/
* config/aarch64/iterators.md (any_or_plus): New code iterator.
* config/aarch64/aarch64.md (extr<mode>5_insn): Use any_or_plus.
(extr<mode>5_insn_alt, extrsi5_insn_uxtw): Likewise.
(extrsi5_insn_uxtw_alt, extrsi5_insn_di): Likewise.
gcc/testsuite/
* gcc.target/aarch64/bitint-args.c: Update expected output.
Diff:
---
gcc/config/aarch64/aarch64.md | 50 ++++++++++++++------------
gcc/config/aarch64/iterators.md | 4 +++
gcc/testsuite/gcc.target/aarch64/bitint-args.c | 4 +--
3 files changed, 33 insertions(+), 25 deletions(-)
diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index 071058dbeb33..cfe730f3732c 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -6194,10 +6194,11 @@
(define_insn "*extr<mode>5_insn"
[(set (match_operand:GPI 0 "register_operand" "=r")
- (ior:GPI (ashift:GPI (match_operand:GPI 1 "register_operand" "r")
- (match_operand 3 "const_int_operand" "n"))
- (lshiftrt:GPI (match_operand:GPI 2 "register_operand" "r")
- (match_operand 4 "const_int_operand" "n"))))]
+ (any_or_plus:GPI
+ (ashift:GPI (match_operand:GPI 1 "register_operand" "r")
+ (match_operand 3 "const_int_operand" "n"))
+ (lshiftrt:GPI (match_operand:GPI 2 "register_operand" "r")
+ (match_operand 4 "const_int_operand" "n"))))]
"UINTVAL (operands[3]) < GET_MODE_BITSIZE (<MODE>mode) &&
(UINTVAL (operands[3]) + UINTVAL (operands[4]) == GET_MODE_BITSIZE
(<MODE>mode))"
"extr\\t%<w>0, %<w>1, %<w>2, %4"
@@ -6208,10 +6209,11 @@
;; so we have to match both orderings.
(define_insn "*extr<mode>5_insn_alt"
[(set (match_operand:GPI 0 "register_operand" "=r")
- (ior:GPI (lshiftrt:GPI (match_operand:GPI 2 "register_operand" "r")
- (match_operand 4 "const_int_operand" "n"))
- (ashift:GPI (match_operand:GPI 1 "register_operand" "r")
- (match_operand 3 "const_int_operand" "n"))))]
+ (any_or_plus:GPI
+ (lshiftrt:GPI (match_operand:GPI 2 "register_operand" "r")
+ (match_operand 4 "const_int_operand" "n"))
+ (ashift:GPI (match_operand:GPI 1 "register_operand" "r")
+ (match_operand 3 "const_int_operand" "n"))))]
"UINTVAL (operands[3]) < GET_MODE_BITSIZE (<MODE>mode)
&& (UINTVAL (operands[3]) + UINTVAL (operands[4])
== GET_MODE_BITSIZE (<MODE>mode))"
@@ -6223,10 +6225,11 @@
(define_insn "*extrsi5_insn_uxtw"
[(set (match_operand:DI 0 "register_operand" "=r")
(zero_extend:DI
- (ior:SI (ashift:SI (match_operand:SI 1 "register_operand" "r")
- (match_operand 3 "const_int_operand" "n"))
- (lshiftrt:SI (match_operand:SI 2 "register_operand" "r")
- (match_operand 4 "const_int_operand" "n")))))]
+ (any_or_plus:SI
+ (ashift:SI (match_operand:SI 1 "register_operand" "r")
+ (match_operand 3 "const_int_operand" "n"))
+ (lshiftrt:SI (match_operand:SI 2 "register_operand" "r")
+ (match_operand 4 "const_int_operand" "n")))))]
"UINTVAL (operands[3]) < 32 &&
(UINTVAL (operands[3]) + UINTVAL (operands[4]) == 32)"
"extr\\t%w0, %w1, %w2, %4"
@@ -6236,10 +6239,11 @@
(define_insn "*extrsi5_insn_uxtw_alt"
[(set (match_operand:DI 0 "register_operand" "=r")
(zero_extend:DI
- (ior:SI (lshiftrt:SI (match_operand:SI 2 "register_operand" "r")
- (match_operand 4 "const_int_operand" "n"))
- (ashift:SI (match_operand:SI 1 "register_operand" "r")
- (match_operand 3 "const_int_operand" "n")))))]
+ (any_or_plus:SI
+ (lshiftrt:SI (match_operand:SI 2 "register_operand" "r")
+ (match_operand 4 "const_int_operand" "n"))
+ (ashift:SI (match_operand:SI 1 "register_operand" "r")
+ (match_operand 3 "const_int_operand" "n")))))]
"UINTVAL (operands[3]) < 32 &&
(UINTVAL (operands[3]) + UINTVAL (operands[4]) == 32)"
"extr\\t%w0, %w1, %w2, %4"
@@ -6248,13 +6252,13 @@
(define_insn "*extrsi5_insn_di"
[(set (match_operand:SI 0 "register_operand" "=r")
- (ior:SI (ashift:SI (match_operand:SI 1 "register_operand" "r")
- (match_operand 3 "const_int_operand" "n"))
- (match_operator:SI 6 "subreg_lowpart_operator"
- [(zero_extract:DI
- (match_operand:DI 2 "register_operand" "r")
- (match_operand 5 "const_int_operand" "n")
- (match_operand 4 "const_int_operand" "n"))])))]
+ (any_or_plus:SI (ashift:SI (match_operand:SI 1 "register_operand" "r")
+ (match_operand 3 "const_int_operand" "n"))
+ (match_operator:SI 6 "subreg_lowpart_operator"
+ [(zero_extract:DI
+ (match_operand:DI 2 "register_operand" "r")
+ (match_operand 5 "const_int_operand" "n")
+ (match_operand 4 "const_int_operand" "n"))])))]
"UINTVAL (operands[3]) < 32
&& UINTVAL (operands[3]) + UINTVAL (operands[4]) == 32
&& INTVAL (operands[3]) == INTVAL (operands[5])"
diff --git a/gcc/config/aarch64/iterators.md b/gcc/config/aarch64/iterators.md
index 9fbd74939882..5bfd6e7d362a 100644
--- a/gcc/config/aarch64/iterators.md
+++ b/gcc/config/aarch64/iterators.md
@@ -2657,6 +2657,10 @@
;; Code iterator for logical operations
(define_code_iterator LOGICAL [and ior xor])
+;; Code iterator for operations that are equivalent when the
+;; two input operands are known have disjoint bits set.
+(define_code_iterator any_or_plus [plus ior xor])
+
;; LOGICAL with plus, for when | gets converted to +.
(define_code_iterator LOGICAL_OR_PLUS [and ior xor plus])
diff --git a/gcc/testsuite/gcc.target/aarch64/bitint-args.c
b/gcc/testsuite/gcc.target/aarch64/bitint-args.c
index e7e1099c303b..06b47246fa50 100644
--- a/gcc/testsuite/gcc.target/aarch64/bitint-args.c
+++ b/gcc/testsuite/gcc.target/aarch64/bitint-args.c
@@ -69,7 +69,7 @@ CHECK_ARG(65)
** f65:
** extr (x[0-9]+), x3, x2, 1
** and (x[0-9]+), x2, 1
-** orr (x[0-9]+), \2, \1, lsl 1
+** add (x[0-9]+), \2, \1, lsl 1
** asr (x[0-9]+), \1, 63
** stp \3, \4, \[x0\]
** ret
@@ -80,7 +80,7 @@ CHECK_ARG(127)
** f127:
** extr (x[0-9]+), x3, x2, 63
** and (x[0-9]+), x2, 9223372036854775807
-** orr (x[0-9]+), \2, \1, lsl 63
+** add (x[0-9]+), \2, \1, lsl 63
** asr (x[0-9]+), \1, 1
** stp \3, \4, \[x0\]
** ret
