From ed9794546db62279199a1cd84b8cdacd14ceab42 Mon Sep 17 00:00:00 2001
From: Xi Ruoyao <xry111@xry111.site>
Date: Fri, 24 Jan 2025 08:32:18 +0800
Subject: [PATCH] LoongArch: Try harder using vrepli instructions to
materialize const vectors
For
a = (v4si){0xdddddddd, 0xdddddddd, 0xdddddddd, 0xdddddddd}
we just want
vrepli.b $vr0, 0xdd
but the compiler actually produces a load:
la.local $r14,.LC0
vld $vr0,$r14,0
It's because we only tried vrepli.d which wouldn't work. Try all vrepli
instructions for const int vector materializing to fix it.
gcc/ChangeLog:
* config/loongarch/loongarch-protos.h
(loongarch_const_vector_vrepli): New function prototype.
* config/loongarch/loongarch.cc (loongarch_const_vector_vrepli):
Implement.
(loongarch_const_insns): Call loongarch_const_vector_vrepli
instead of loongarch_const_vector_same_int_p.
(loongarch_split_vector_move_p): Likewise.
(loongarch_output_move): Use loongarch_const_vector_vrepli to
pun operend[1] into a better mode if it's a const int vector,
and decide the suffix of [x]vrepli with the new mode.
* config/loongarch/constraints.md (YI): Call
loongarch_const_vector_vrepli instead of
loongarch_const_vector_same_int_p.
gcc/testsuite/ChangeLog:
* gcc.target/loongarch/vrepli.c: New test.
---
gcc/config/loongarch/constraints.md | 2 +-
gcc/config/loongarch/loongarch-protos.h | 1 +
gcc/config/loongarch/loongarch.cc | 34 ++++++++++++++++++---
gcc/testsuite/gcc.target/loongarch/vrepli.c | 15 +++++++++
4 files changed, 46 insertions(+), 6 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/loongarch/vrepli.c
diff --git a/gcc/config/loongarch/constraints.md b/gcc/config/loongarch/constraints.md
index a7c31c2c4e0d..97a4e4e35d32 100644
--- a/gcc/config/loongarch/constraints.md
+++ b/gcc/config/loongarch/constraints.md
@@ -301,7 +301,7 @@
A replicated vector const in which the replicated value is in the range
[-512,511]."
(and (match_code "const_vector")
- (match_test "loongarch_const_vector_same_int_p (op, mode, -512, 511)")))
+ (match_test "loongarch_const_vector_vrepli (op, mode)")))
(define_constraint "YC"
"@internal
diff --git a/gcc/config/loongarch/loongarch-protos.h b/gcc/config/loongarch/loongarch-protos.h
index e7b318143bfe..6d1075989a87 100644
--- a/gcc/config/loongarch/loongarch-protos.h
+++ b/gcc/config/loongarch/loongarch-protos.h
@@ -121,6 +121,7 @@ extern bool loongarch_const_vector_same_int_p (rtx, machine_mode,
extern bool loongarch_const_vector_shuffle_set_p (rtx, machine_mode);
extern bool loongarch_const_vector_bitimm_set_p (rtx, machine_mode);
extern bool loongarch_const_vector_bitimm_clr_p (rtx, machine_mode);
+extern rtx loongarch_const_vector_vrepli (rtx, machine_mode);
extern rtx loongarch_lsx_vec_parallel_const_half (machine_mode, bool);
extern rtx loongarch_gen_const_int_vector (machine_mode, HOST_WIDE_INT);
extern enum reg_class loongarch_secondary_reload_class (enum reg_class,
diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
index 495b62309d61..404deedd8f23 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -1846,6 +1846,28 @@ loongarch_const_vector_shuffle_set_p (rtx op, machine_mode mode)
return true;
}
+rtx
+loongarch_const_vector_vrepli (rtx x, machine_mode mode)
+{
+ int size = GET_MODE_SIZE (mode);
+
+ if (GET_CODE (x) != CONST_VECTOR
+ || GET_MODE_CLASS (mode) != MODE_VECTOR_INT)
+ return NULL_RTX;
+
+ for (scalar_int_mode elem_mode: {QImode, HImode, SImode, DImode})
+ {
+ machine_mode new_mode =
+ mode_for_vector (elem_mode, size / GET_MODE_SIZE (elem_mode))
+ .require ();
+ rtx op = lowpart_subreg (new_mode, x, mode);
+ if (loongarch_const_vector_same_int_p (op, new_mode, -512, 511))
+ return op;
+ }
+
+ return NULL_RTX;
+}
+
/* Return true if rtx constants of mode MODE should be put into a small
data section. */
@@ -2501,7 +2523,7 @@ loongarch_const_insns (rtx x)
case CONST_VECTOR:
if ((LSX_SUPPORTED_MODE_P (GET_MODE (x))
|| LASX_SUPPORTED_MODE_P (GET_MODE (x)))
- && loongarch_const_vector_same_int_p (x, GET_MODE (x), -512, 511))
+ && loongarch_const_vector_vrepli (x, GET_MODE (x)))
return 1;
/* Fall through. */
case CONST_DOUBLE:
@@ -4656,7 +4678,7 @@ loongarch_split_vector_move_p (rtx dest, rtx src)
/* Check for vector set to an immediate const vector with valid replicated
element. */
if (FP_REG_RTX_P (dest)
- && loongarch_const_vector_same_int_p (src, GET_MODE (src), -512, 511))
+ && loongarch_const_vector_vrepli (src, GET_MODE (src)))
return false;
/* Check for vector load zero immediate. */
@@ -4792,13 +4814,15 @@ loongarch_output_move (rtx *operands)
&& src_code == CONST_VECTOR
&& CONST_INT_P (CONST_VECTOR_ELT (src, 0)))
{
- gcc_assert (loongarch_const_vector_same_int_p (src, mode, -512, 511));
+ operands[1] = loongarch_const_vector_vrepli (src, mode);
+ gcc_assert (operands[1]);
+
switch (GET_MODE_SIZE (mode))
{
case 16:
- return "vrepli.%v0\t%w0,%E1";
+ return "vrepli.%v1\t%w0,%E1";
case 32:
- return "xvrepli.%v0\t%u0,%E1";
+ return "xvrepli.%v1\t%u0,%E1";
default: gcc_unreachable ();
}
}
diff --git a/gcc/testsuite/gcc.target/loongarch/vrepli.c b/gcc/testsuite/gcc.target/loongarch/vrepli.c
new file mode 100644
index 000000000000..8deeb4788904
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/vrepli.c
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mlasx" } */
+/* { dg-final { scan-assembler "\tvrepli\\.b\t\\\$vr\[0-9\]+,-35" } } */
+/* { dg-final { scan-assembler "\txvrepli\\.b\t\\\$xr\[0-9\]+,-35" } } */
+
+int f __attribute__((vector_size (16)));
+int g __attribute__((vector_size (32)));
+
+void
+test (void)
+{
+ constexpr int x = (int) 0xdddddddd;
+ f = (typeof(f)){x, x, x, x};
+ g = (typeof(g)){x, x, x, x, x, x, x, x};
+}
--
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