https://gcc.gnu.org/g:3b4588e41dc54d01b95e7b05e1f493c402ec39d2
commit 3b4588e41dc54d01b95e7b05e1f493c402ec39d2
Author: Michael Meissner <meiss...@linux.ibm.com>
Date: Wed Jul 9 01:32:46 2025 -0400
PR target/117251: Improve vector and to vector and fusion
See the following post for a complete explanation of what the patches
for PR target/117251:
* https://gcc.gnu.org/pipermail/gcc-patches/2025-June/686474.html
This is patch #1 of 45 to generate the 'XXEVAL' instruction on power10
and power11 instead of using the Altivec 'VAND' instruction feeding
into 'VAND'. The 'XXEVAL' instruction can use all 64 vector registers,
instead of the 32 registers that traditional Altivec vector
instructions use. By allowing all of the vector registers to be used,
it reduces the amount of spilling that a large benchmark generated.
Currently the following code:
vector int a, b, c, d;
a = (c & d) & b;
Generates:
vand t,c,d
vand a,t,b
Now in addition with this patch, if the arguments or result is
allocated to a traditional FPR register, the GCC compiler will now
generate the following code instead of adding vector move instructions:
xxeval a,b,c,1
Since fusion using 2 Altivec instructions is slightly faster than using
the 'XXEVAL' instruction we prefer to generate the Altivec instructions
if we can. In addition, because 'XXEVAL' is a prefixed instruction, it
possibly might generate an extra NOP instruction to align the 'XXEVAL'
instruction.
I have tested these patches on both big endian and little endian
PowerPC servers, with no regressions. Can I check these patchs into
the trunk?
2025-07-09 Michael Meissner <meiss...@linux.ibm.com>
gcc/
PR target/117251
* config/rs6000/fusion.md: Regenerate.
* config/rs6000/genfusion.pl (gen_logical_addsubf): Add
support to generate vector/vector and/and fusion if XXEVAL is
supported.
* config/rs6000/predicates.md (vector_fusion_operand): New
predicate.
* config/rs6000/rs6000.h (TARGET_XXEVAL): New macro.
* config/rs6000/rs6000.md (isa attribute): Add xxeval.
(enabled attribute): Add support for XXEVAL support.
Diff:
---
gcc/config/rs6000/fusion.md | 15 ++++++-----
gcc/config/rs6000/genfusion.pl | 58 ++++++++++++++++++++++++++++++++++++++---
gcc/config/rs6000/predicates.md | 12 +++++++++
gcc/config/rs6000/rs6000.h | 4 +++
gcc/config/rs6000/rs6000.md | 7 ++++-
5 files changed, 85 insertions(+), 11 deletions(-)
diff --git a/gcc/config/rs6000/fusion.md b/gcc/config/rs6000/fusion.md
index 621b346f9eb9..d24837d68d83 100644
--- a/gcc/config/rs6000/fusion.md
+++ b/gcc/config/rs6000/fusion.md
@@ -1871,20 +1871,23 @@
;; logical-logical fusion pattern generated by gen_logical_addsubf
;; vector vand -> vand
(define_insn "*fuse_vand_vand"
- [(set (match_operand:VM 3 "altivec_register_operand" "=&0,&1,&v,v")
- (and:VM (and:VM (match_operand:VM 0 "altivec_register_operand"
"v,v,v,v")
- (match_operand:VM 1 "altivec_register_operand"
"%v,v,v,v"))
- (match_operand:VM 2 "altivec_register_operand" "v,v,v,v")))
- (clobber (match_scratch:VM 4 "=X,X,X,&v"))]
+ [(set (match_operand:VM 3 "vector_fusion_operand" "=&0,&1,&v,wa,v")
+ (and:VM (and:VM (match_operand:VM 0 "vector_fusion_operand"
"v,v,v,wa,v")
+ (match_operand:VM 1 "vector_fusion_operand"
"%v,v,v,wa,v"))
+ (match_operand:VM 2 "vector_fusion_operand" "v,v,v,wa,v")))
+ (clobber (match_scratch:VM 4 "=X,X,X,X,&v"))]
"(TARGET_P10_FUSION)"
"@
vand %3,%1,%0\;vand %3,%3,%2
vand %3,%1,%0\;vand %3,%3,%2
vand %3,%1,%0\;vand %3,%3,%2
+ xxeval %x3,%x2,%x1,%x0,1
vand %4,%1,%0\;vand %3,%4,%2"
[(set_attr "type" "fused_vector")
(set_attr "cost" "6")
- (set_attr "length" "8")])
+ (set_attr "length" "8")
+ (set_attr "prefixed" "*,*,*,yes,*")
+ (set_attr "isa" "*,*,*,xxeval,*")])
;; logical-logical fusion pattern generated by gen_logical_addsubf
;; vector vandc -> vand
diff --git a/gcc/config/rs6000/genfusion.pl b/gcc/config/rs6000/genfusion.pl
index e5d3b1ee449d..351a4d914a4a 100755
--- a/gcc/config/rs6000/genfusion.pl
+++ b/gcc/config/rs6000/genfusion.pl
@@ -211,25 +211,33 @@ sub gen_logical_addsubf
$inner_comp, $inner_inv, $inner_rtl, $inner_op, $both_commute, $c4,
$bc, $inner_arg0, $inner_arg1, $inner_exp, $outer_arg2, $outer_exp,
$ftype, $insn, $is_subf, $is_rsubf, $outer_32, $outer_42,$outer_name,
- $fuse_type);
- KIND: foreach $kind ('scalar','vector') {
+ $fuse_type, $xxeval, $c5, $vect_pred, $vect_inner_arg0,
$vect_inner_arg1,
+ $vect_inner_exp, $vect_outer_arg2, $vect_outer_exp);
+
+ my %xxeval_fusions = (
+ "vand_vand" => 1,
+ );
+
+ KIND: foreach $kind ('scalar','vector') {
@outer_ops = @logicals;
if ( $kind eq 'vector' ) {
$vchr = "v";
$mode = "VM";
$pred = "altivec_register_operand";
+ $vect_pred = "vector_fusion_operand";
$constraint = "v";
$fuse_type = "fused_vector";
} else {
$vchr = "";
$mode = "GPR";
- $pred = "gpc_reg_operand";
+ $vect_pred = $pred = "gpc_reg_operand";
$constraint = "r";
$fuse_type = "fused_arith_logical";
push (@outer_ops, @addsub);
push (@outer_ops, ( "rsubf" ));
}
$c4 = "${constraint},${constraint},${constraint},${constraint}";
+ $c5 = "${constraint},${constraint},${constraint},wa,${constraint}";
OUTER: foreach $outer ( @outer_ops ) {
$outer_name = "${vchr}${outer}";
$is_subf = ( $outer eq "subf" );
@@ -263,23 +271,33 @@ sub gen_logical_addsubf
$bc = ""; if ( $both_commute ) { $bc = "%"; }
$inner_arg0 = "(match_operand:${mode} 0 \"${pred}\" \"${c4}\")";
$inner_arg1 = "(match_operand:${mode} 1 \"${pred}\" \"${bc}${c4}\")";
+ $vect_inner_arg0 = "(match_operand:${mode} 0 \"${vect_pred}\"
\"${c5}\")";
+ $vect_inner_arg1 = "(match_operand:${mode} 1 \"${vect_pred}\"
\"${bc}${c5}\")";
if ( ($inner_comp & 1) == 1 ) {
$inner_arg0 = "(not:${mode} $inner_arg0)";
+ $vect_inner_arg0 = "(not:${mode} $vect_inner_arg0)";
}
if ( ($inner_comp & 2) == 2 ) {
$inner_arg1 = "(not:${mode} $inner_arg1)";
+ $vect_inner_arg1 = "(not:${mode} $vect_inner_arg1)";
}
$inner_exp = "(${inner_rtl}:${mode} ${inner_arg0}
${inner_arg1})";
+ $vect_inner_exp = "(${inner_rtl}:${mode} ${vect_inner_arg0}
+ ${vect_inner_arg1})";
if ( $inner_inv == 1 ) {
$inner_exp = "(not:${mode} $inner_exp)";
+ $vect_inner_exp = "(not:${mode} $vect_inner_exp)";
}
$outer_arg2 = "(match_operand:${mode} 2 \"${pred}\" \"${c4}\")";
+ $vect_outer_arg2 = "(match_operand:${mode} 2 \"${vect_pred}\"
\"${c5}\")";
if ( ($outer_comp & 1) == 1 ) {
$outer_arg2 = "(not:${mode} $outer_arg2)";
+ $vect_outer_arg2 = "(not:${mode} $vect_outer_arg2)";
}
if ( ($outer_comp & 2) == 2 ) {
$inner_exp = "(not:${mode} $inner_exp)";
+ $vect_inner_exp = "(not:${mode} $vect_inner_exp)";
}
if ( $is_subf ) {
$outer_32 = "%2,%3";
@@ -291,15 +309,23 @@ sub gen_logical_addsubf
if ( $is_rsubf == 1 ) {
$outer_exp = "(${outer_rtl}:${mode} ${outer_arg2}
${inner_exp})";
+ $vect_outer_exp = "(${outer_rtl}:${mode} ${vect_outer_arg2}
+ ${vect_inner_exp})";
} else {
$outer_exp = "(${outer_rtl}:${mode} ${inner_exp}
${outer_arg2})";
+ $vect_outer_exp = "(${outer_rtl}:${mode} ${vect_inner_exp}
+ ${vect_outer_arg2})";
}
if ( $outer_inv == 1 ) {
$outer_exp = "(not:${mode} $outer_exp)";
+ $vect_outer_exp = "(not:${mode} $vect_outer_exp)";
}
- $insn = <<"EOF";
+ # See if we can use xxeval on vector fusion
+ $xxeval = $xxeval_fusions{"${inner_op}_${outer_name}"};
+ if (!$xxeval) {
+ $insn = <<"EOF";
;; $ftype fusion pattern generated by gen_logical_addsubf
;; $kind $inner_op -> $outer_name
@@ -318,6 +344,30 @@ sub gen_logical_addsubf
(set_attr "length" "8")])
EOF
+ } else {
+ $insn = <<"EOF";
+
+;; $ftype fusion pattern generated by gen_logical_addsubf
+;; $kind $inner_op -> $outer_name
+(define_insn "*fuse_${inner_op}_${outer_name}"
+ [(set (match_operand:${mode} 3 "${vect_pred}"
"=&0,&1,&${constraint},wa,${constraint}")
+ ${vect_outer_exp})
+ (clobber (match_scratch:${mode} 4 "=X,X,X,X,&${constraint}"))]
+ "(TARGET_P10_FUSION)"
+ "@
+ ${inner_op} %3,%1,%0\\;${outer_op} %3,${outer_32}
+ ${inner_op} %3,%1,%0\\;${outer_op} %3,${outer_32}
+ ${inner_op} %3,%1,%0\\;${outer_op} %3,${outer_32}
+ xxeval %x3,%x2,%x1,%x0,${xxeval}
+ ${inner_op} %4,%1,%0\\;${outer_op} %3,${outer_42}"
+ [(set_attr "type" "$fuse_type")
+ (set_attr "cost" "6")
+ (set_attr "length" "8")
+ (set_attr "prefixed" "*,*,*,yes,*")
+ (set_attr "isa" "*,*,*,xxeval,*")])
+EOF
+ }
+
print $insn;
}
}
diff --git a/gcc/config/rs6000/predicates.md b/gcc/config/rs6000/predicates.md
index 647e89afb6a7..a6010a8c8a81 100644
--- a/gcc/config/rs6000/predicates.md
+++ b/gcc/config/rs6000/predicates.md
@@ -119,6 +119,18 @@
return VSX_REGNO_P (REGNO (op));
})
+;; Return 1 if op is a register that can be used for vector fusion. If XXEVAL
+;; is supported, return true for all VSX registers, otherwise the fusion is
+;; limited to Altivec registers since the machine only fuses Altivec
+;; operations.
+(define_predicate "vector_fusion_operand"
+ (match_operand 0 "register_operand")
+{
+ return (TARGET_XXEVAL
+ ? vsx_register_operand (op, mode)
+ : altivec_register_operand (op, mode));
+})
+
;; Return 1 if op is a vector register that operates on floating point vectors
;; (either altivec or VSX).
(define_predicate "vfloat_operand"
diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h
index db6112a09e11..632c3cc8d135 100644
--- a/gcc/config/rs6000/rs6000.h
+++ b/gcc/config/rs6000/rs6000.h
@@ -499,6 +499,10 @@ extern int rs6000_vector_align[];
#define TARGET_MINMAX (TARGET_HARD_FLOAT && TARGET_PPC_GFXOPT \
&& (TARGET_P9_MINMAX || !flag_trapping_math))
+/* Enable XXEVAL support if we support prefixed instructions and at least
+ power10. */
+#define TARGET_XXEVAL (TARGET_POWER10 && TARGET_PREFIXED)
+
/* In switching from using target_flags to using rs6000_isa_flags, the options
machinery creates OPTION_MASK_<xxx> instead of MASK_<xxx>. The MASK_<xxxx>
options that have not yet been replaced by their OPTION_MASK_<xxx>
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index 9c718ca2a226..e03a639ba868 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -369,7 +369,7 @@
(const (symbol_ref "(enum attr_cpu) rs6000_tune")))
;; The ISA we implement.
-(define_attr "isa" "any,p5,p6,p7,p7v,p8,p8v,p9,p9v,p9kf,p9tf,p10"
+(define_attr "isa" "any,p5,p6,p7,p7v,p8,p8v,p9,p9v,p9kf,p9tf,p10,xxeval"
(const_string "any"))
;; Is this alternative enabled for the current CPU/ISA/etc.?
@@ -421,6 +421,11 @@
(and (eq_attr "isa" "p10")
(match_test "TARGET_POWER10"))
(const_int 1)
+
+ (and (eq_attr "isa" "xxeval")
+ (match_test "TARGET_PREFIXED && TARGET_XXEVAL"))
+ (const_int 1)
+
] (const_int 0)))
;; If this instruction is microcoded on the CELL processor
