https://gcc.gnu.org/g:f788324c724240b6280243119a6fa30f3d37b467
commit r16-1778-gf788324c724240b6280243119a6fa30f3d37b467
Author: Richard Biener <rguent...@suse.de>
Date: Mon Jun 30 11:23:49 2025 +0200
Handle SLP build operand swapping for ternaries and calls
The following adds SLP build operand swapping for .FMA which is
a ternary operator and a call. The current code only handles
binary operators in assignments, thus the patch extends this to
handle both calls and assignments as well as binary and ternary
operators.
* tree-vect-slp.cc (vect_build_slp_2): Handle ternary
and call operators when swapping operands.
* gcc.target/i386/vect-pr82426.c: Pass explicit -ffp-contract=fast.
* gcc.target/i386/vect-pr82426-2.c: New testcase variant with
-ffp-contract=on.
Diff:
---
gcc/testsuite/gcc.target/i386/vect-pr82426-2.c | 31 +++++++++++++++++++++
gcc/testsuite/gcc.target/i386/vect-pr82426.c | 2 +-
gcc/tree-vect-slp.cc | 37 +++++++++++++++++++-------
3 files changed, 60 insertions(+), 10 deletions(-)
diff --git a/gcc/testsuite/gcc.target/i386/vect-pr82426-2.c
b/gcc/testsuite/gcc.target/i386/vect-pr82426-2.c
new file mode 100644
index 000000000000..525940866ad7
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/vect-pr82426-2.c
@@ -0,0 +1,31 @@
+/* i?86 does not have V2SF, x32 does though. */
+/* { dg-do compile { target { ! ia32 } } } */
+/* { dg-options "-O3 -mavx -mfma -ffp-contract=on" } */
+
+struct Matrix
+{
+ float m11;
+ float m12;
+ float m21;
+ float m22;
+ float dx;
+ float dy;
+};
+
+struct Matrix multiply(const struct Matrix *a, const struct Matrix *b)
+{
+ struct Matrix out;
+ out.m11 = a->m11*b->m11 + a->m12*b->m21;
+ out.m12 = a->m11*b->m12 + a->m12*b->m22;
+ out.m21 = a->m21*b->m11 + a->m22*b->m21;
+ out.m22 = a->m21*b->m12 + a->m22*b->m22;
+
+ out.dx = a->dx*b->m11 + a->dy*b->m21 + b->dx;
+ out.dy = a->dx*b->m12 + a->dy*b->m22 + b->dy;
+ return out;
+}
+
+/* The whole kernel should be vectorized with V4SF and V2SF operations. */
+/* { dg-final { scan-assembler-times "vadd" 1 } } */
+/* { dg-final { scan-assembler-times "vmul" 2 } } */
+/* { dg-final { scan-assembler-times "vfma" 2 } } */
diff --git a/gcc/testsuite/gcc.target/i386/vect-pr82426.c
b/gcc/testsuite/gcc.target/i386/vect-pr82426.c
index 03b10adff9b6..8ce8fe78a91b 100644
--- a/gcc/testsuite/gcc.target/i386/vect-pr82426.c
+++ b/gcc/testsuite/gcc.target/i386/vect-pr82426.c
@@ -1,6 +1,6 @@
/* i?86 does not have V2SF, x32 does though. */
/* { dg-do compile { target { ! ia32 } } } */
-/* { dg-options "-O3 -mavx -mfma" } */
+/* { dg-options "-O3 -mavx -mfma -ffp-contract=fast" } */
struct Matrix
{
diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 1a703a9bae4a..7a828cadbd53 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -2849,9 +2849,10 @@ out:
&& matches[0]
/* ??? For COND_EXPRs we can swap the comparison operands
as well as the arms under some constraints. */
- && nops == 2
+ && (nops == 2 || nops == 3)
&& oprnds_info[1]->first_dt == vect_internal_def
- && is_gimple_assign (stmt_info->stmt)
+ && (is_gimple_assign (stmt_info->stmt)
+ || is_gimple_call (stmt_info->stmt))
/* Swapping operands for reductions breaks assumptions later on. */
&& STMT_VINFO_REDUC_IDX (stmt_info) == -1)
{
@@ -2866,14 +2867,32 @@ out:
continue;
stmt_vec_info stmt_info = stmts[j];
/* Verify if we can swap operands of this stmt. */
- gassign *stmt = dyn_cast <gassign *> (stmt_info->stmt);
- if (!stmt
- || !commutative_tree_code (gimple_assign_rhs_code (stmt)))
+ if (gassign *stmt = dyn_cast <gassign *> (stmt_info->stmt))
{
- if (!swap_not_matching)
- goto fail;
- swap_not_matching = false;
- break;
+ tree_code code = gimple_assign_rhs_code (stmt);
+ if (! commutative_tree_code (code)
+ && ! commutative_ternary_tree_code (code))
+ {
+ if (!swap_not_matching)
+ goto fail;
+ swap_not_matching = false;
+ break;
+ }
+ }
+ else if (gcall *call = dyn_cast <gcall *> (stmt_info->stmt))
+ {
+ internal_fn fn = (gimple_call_internal_p (call)
+ ? gimple_call_internal_fn (call)
+ : IFN_LAST);
+ if ((! commutative_binary_fn_p (fn)
+ && ! commutative_ternary_fn_p (fn))
+ || first_commutative_argument (fn) != 0)
+ {
+ if (!swap_not_matching)
+ goto fail;
+ swap_not_matching = false;
+ break;
+ }
}
}
}
