From d953c2c5714ed8503c4ae1b7d059a62e4e9a0624 Mon Sep 17 00:00:00 2001
From: Tsung Chun Lin <tclin914@gmail.com>
Date: Tue, 7 Jan 2025 14:48:31 -0700
Subject: [PATCH] Prefer scalar_int_mode if the size - 1 is equal to
UNITS_PER_WORD.
Don't use the QI vector if its size is equal to UNITS_PER_WORD for
better code generation.
Before patch:
vsetivli zero,4,e8,mf4,ta,ma
vmv.v.i v1,0
addi a4,sp,12
vse8.v v1,0(a4)
After patch:
sw zero,12(sp)
gcc/
* expr.cc (widest_fixed_size_mode_for_size): Prefer scalar modes
over vector modes in more cases.
gcc/testsuite/
* gcc.target/riscv/rvv/autovec/pr113469.c: Update expected output.
* gcc.target/riscv/rvv/base/movqi-1.c: New test.
---
gcc/expr.cc | 3 ++-
.../gcc.target/riscv/rvv/autovec/pr113469.c | 1 -
.../gcc.target/riscv/rvv/base/movqi-1.c | 18 ++++++++++++++++++
3 files changed, 20 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/movqi-1.c
diff --git a/gcc/expr.cc b/gcc/expr.cc
index 635bb9efa9eb..235e79546113 100644
--- a/gcc/expr.cc
+++ b/gcc/expr.cc
@@ -1062,12 +1062,13 @@ widest_fixed_size_mode_for_size (unsigned int size, by_pieces_operation op)
gcc_checking_assert (size > 1);
/* Use QI vector only if size is wider than a WORD. */
- if (can_use_qi_vectors (op) && size > UNITS_PER_WORD)
+ if (can_use_qi_vectors (op))
{
machine_mode mode;
fixed_size_mode candidate;
FOR_EACH_MODE_IN_CLASS (mode, MODE_VECTOR_INT)
if (is_a<fixed_size_mode> (mode, &candidate)
+ && GET_MODE_SIZE (candidate) > UNITS_PER_WORD
&& GET_MODE_INNER (candidate) == QImode)
{
if (GET_MODE_SIZE (candidate) >= size)
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr113469.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr113469.c
index 52e2580c53e6..6549ae61c672 100644
--- a/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr113469.c
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr113469.c
@@ -51,5 +51,4 @@ void p(int buf, __builtin_va_list ab, int q) {
} while (k);
}
-/* { dg-final { scan-assembler-times {vsetivli\tzero,\s*4,\s*e8,\s*mf4,\s*t[au],\s*m[au]} 1 } } */
/* { dg-final { scan-assembler-times {vsetivli\tzero,\s*8,\s*e8,\s*mf2,\s*t[au],\s*m[au]} 1 } } */
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/base/movqi-1.c b/gcc/testsuite/gcc.target/riscv/rvv/base/movqi-1.c
new file mode 100644
index 000000000000..bc461035e5b8
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/base/movqi-1.c
@@ -0,0 +1,18 @@
+/* Test that we do not use QI vector to initilize the memory if the
+ * size of QI vector isn't larger than UNITS_PER_WORD */
+/* { dg-do compile } */
+/* { dg-options "-march=rv32gcv -mabi=ilp32 -O3" } */
+
+struct s {
+ int a;
+ int b : 1;
+};
+
+void q(struct s*);
+
+void g() {
+ struct s r = { 15, 0 };
+ q(&r);
+}
+
+/* { dg-final { scan-assembler-times {sw\tzero,12\(sp\)} 1 } } */
--
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