https://gcc.gnu.org/g:6be1b9e94d9a2ead15e3625e833f1e34503ab803
commit r15-7688-g6be1b9e94d9a2ead15e3625e833f1e34503ab803
Author: Robin Dapp <rd...@ventanamicro.com>
Date: Fri Feb 21 17:08:16 2025 +0100
RISC-V: Include pattern stmts for dynamic LMUL computation [PR114516].
When scanning for program points, i.e. vector statements, we're missing
pattern statements. In PR114516 this becomes obvious as we choose
LMUL=8 assuming there are only three statements but the divmod pattern
adds another three. Those push us beyond four registers so we need to
switch to LMUL=4.
This patch adds pattern statements to the program points which helps
calculate a better register pressure estimate.
PR target/114516
gcc/ChangeLog:
* config/riscv/riscv-vector-costs.cc (compute_estimated_lmul):
Add pattern statements to program points.
gcc/testsuite/ChangeLog:
* gcc.dg/vect/costmodel/riscv/rvv/pr114516.c: New test.
Diff:
---
gcc/config/riscv/riscv-vector-costs.cc | 29 ++++++++++++++++++++++
.../gcc.dg/vect/costmodel/riscv/rvv/pr114516.c | 29 ++++++++++++++++++++++
2 files changed, 58 insertions(+)
diff --git a/gcc/config/riscv/riscv-vector-costs.cc
b/gcc/config/riscv/riscv-vector-costs.cc
index d4571b65e193..167375ca7516 100644
--- a/gcc/config/riscv/riscv-vector-costs.cc
+++ b/gcc/config/riscv/riscv-vector-costs.cc
@@ -217,6 +217,35 @@ compute_local_program_points (
"program point %d: %G", info.point,
gsi_stmt (si));
}
+
+ /* If the statement is part of a pattern, also add the other
+ pattern statements. */
+ gimple_seq pattern_def_seq;
+ if (STMT_VINFO_IN_PATTERN_P (stmt_info)
+ && (pattern_def_seq = STMT_VINFO_PATTERN_DEF_SEQ (stmt_info)))
+ {
+ gimple_stmt_iterator si2;
+
+ for (si2 = gsi_start (pattern_def_seq);
+ !gsi_end_p (si2);
+ gsi_next (&si2))
+ {
+ stmt_vec_info pattern_def_stmt_info
+ = vinfo->lookup_stmt (gsi_stmt (si2));
+ if (STMT_VINFO_RELEVANT_P (pattern_def_stmt_info)
+ || STMT_VINFO_LIVE_P (pattern_def_stmt_info))
+ {
+ stmt_point info = {point, gsi_stmt (si2),
+ pattern_def_stmt_info};
+ program_points.safe_push (info);
+ point++;
+ if (dump_enabled_p ())
+ dump_printf_loc (MSG_NOTE, vect_location,
+ "program point %d: %G",
+ info.point, gsi_stmt (si2));
+ }
+ }
+ }
}
program_points_per_bb.put (bb, program_points);
}
diff --git a/gcc/testsuite/gcc.dg/vect/costmodel/riscv/rvv/pr114516.c
b/gcc/testsuite/gcc.dg/vect/costmodel/riscv/rvv/pr114516.c
new file mode 100644
index 000000000000..55d036c3ad7b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/costmodel/riscv/rvv/pr114516.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gcv_zba_zbb -mabi=lp64d -mrvv-max-lmul=dynamic -O3
-fdump-tree-vect-details" } */
+
+typedef float real_t;
+__attribute__((aligned(64))) real_t a[32000];
+real_t s315()
+{
+ for (int i = 0; i < 32000; i++)
+ a[i] = (i * 7) % 32000;
+ real_t x, chksum;
+ int index;
+ for (int nl = 0; nl < 256; nl++) {
+ x = a[0];
+ index = 0;
+ for (int i = 0; i < 32000; ++i) {
+ if (a[i] > x) {
+ x = a[i];
+ index = i;
+ }
+ }
+ chksum = x + (real_t) index;
+ }
+ return index + x + 1;
+}
+
+/* { dg-final { scan-assembler {e32,m4} } } */
+/* { dg-final { scan-assembler-not {e32,m8} } } */
+/* { dg-final { scan-assembler-not {csrr} } } */
+/* { dg-final { scan-tree-dump-times "Preferring smaller LMUL loop because it
has unexpected spills" 1 "vect" } } */
