Consider
c &= 0xfff;
a &= ~0xfff;
b &= ~0xfff;
a |= c;
b |= c;
This can be done with 2 bstrins instructions. But we need to recognize
it in loongarch_rtx_costs or the compiler will not propagate "c & 0xfff"
forward.
gcc/ChangeLog:
* config/loongarch/loongarch.cc:
(loongarch_use_bstrins_for_ior_with_mask): Split the main logic
into ...
(loongarch_use_bstrins_for_ior_with_mask_1): ... here.
(loongarch_rtx_costs): Special case for IOR those can be
implemented with bstrins.
gcc/testsuite/ChangeLog;
* gcc.target/loongarch/bstrins-3.c: New test.
---
Bootstrapped and regtested on loongarch64-linux-gnu. Ok for trunk?
gcc/config/loongarch/loongarch.cc | 73 ++++++++++++++-----
.../gcc.target/loongarch/bstrins-3.c | 16 ++++
2 files changed, 72 insertions(+), 17 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/loongarch/bstrins-3.c
diff --git a/gcc/config/loongarch/loongarch.cc
b/gcc/config/loongarch/loongarch.cc
index 6ec3ee62502..256b76d044b 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -3681,6 +3681,27 @@ loongarch_set_reg_reg_piece_cost (machine_mode mode,
unsigned int units)
return COSTS_N_INSNS ((GET_MODE_SIZE (mode) + units - 1) / units);
}
+static int
+loongarch_use_bstrins_for_ior_with_mask_1 (machine_mode mode,
+ unsigned HOST_WIDE_INT mask1,
+ unsigned HOST_WIDE_INT mask2)
+{
+ if (mask1 != ~mask2 || !mask1 || !mask2)
+ return 0;
+
+ /* Try to avoid a right-shift. */
+ if (low_bitmask_len (mode, mask1) != -1)
+ return -1;
+
+ if (low_bitmask_len (mode, mask2 >> (ffs_hwi (mask2) - 1)) != -1)
+ return 1;
+
+ if (low_bitmask_len (mode, mask1 >> (ffs_hwi (mask1) - 1)) != -1)
+ return -1;
+
+ return 0;
+}
+
/* Return the cost of moving between two registers of mode MODE. */
static int
@@ -3812,6 +3833,38 @@ loongarch_rtx_costs (rtx x, machine_mode mode, int
outer_code,
/* Fall through. */
case IOR:
+ {
+ rtx op[2] = {XEXP (x, 0), XEXP (x, 1)};
+ if (GET_CODE (op[0]) == AND && GET_CODE (op[1]) == AND
+ && (mode == SImode || (TARGET_64BIT && mode == DImode)))
+ {
+ rtx rtx_mask0 = XEXP (op[0], 1), rtx_mask1 = XEXP (op[1], 1);
+ if (CONST_INT_P (rtx_mask0) && CONST_INT_P (rtx_mask1))
+ {
+ unsigned HOST_WIDE_INT mask0 = UINTVAL (rtx_mask0);
+ unsigned HOST_WIDE_INT mask1 = UINTVAL (rtx_mask1);
+ if (loongarch_use_bstrins_for_ior_with_mask_1 (mode,
+ mask0,
+ mask1))
+ {
+ /* A bstrins instruction */
+ *total = COSTS_N_INSNS (1);
+
+ /* A srai instruction */
+ if (low_bitmask_len (mode, mask0) == -1
+ && low_bitmask_len (mode, mask1) == -1)
+ *total += COSTS_N_INSNS (1);
+
+ for (int i = 0; i < 2; i++)
+ *total += set_src_cost (XEXP (op[i], 0), mode, speed);
+
+ return true;
+ }
+ }
+ }
+ }
+
+ /* Fall through. */
case XOR:
/* Double-word operations use two single-word operations. */
*total = loongarch_binary_cost (x, COSTS_N_INSNS (1), COSTS_N_INSNS (2),
@@ -5796,23 +5849,9 @@ bool loongarch_pre_reload_split (void)
int
loongarch_use_bstrins_for_ior_with_mask (machine_mode mode, rtx *op)
{
- unsigned HOST_WIDE_INT mask1 = UINTVAL (op[2]);
- unsigned HOST_WIDE_INT mask2 = UINTVAL (op[4]);
-
- if (mask1 != ~mask2 || !mask1 || !mask2)
- return 0;
-
- /* Try to avoid a right-shift. */
- if (low_bitmask_len (mode, mask1) != -1)
- return -1;
-
- if (low_bitmask_len (mode, mask2 >> (ffs_hwi (mask2) - 1)) != -1)
- return 1;
-
- if (low_bitmask_len (mode, mask1 >> (ffs_hwi (mask1) - 1)) != -1)
- return -1;
-
- return 0;
+ return loongarch_use_bstrins_for_ior_with_mask_1 (mode,
+ UINTVAL (op[2]),
+ UINTVAL (op[4]));
}
/* Rewrite a MEM for simple load/store under -mexplicit-relocs=auto
diff --git a/gcc/testsuite/gcc.target/loongarch/bstrins-3.c
b/gcc/testsuite/gcc.target/loongarch/bstrins-3.c
new file mode 100644
index 00000000000..13762bdef42
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/bstrins-3.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-rtl-final" } */
+/* { dg-final { scan-rtl-dump-times "insv\[sd\]i" 2 "final" } } */
+
+struct X {
+ long a, b;
+};
+
+struct X
+test (long a, long b, long c)
+{
+ c &= 0xfff;
+ a &= ~0xfff;
+ b &= ~0xfff;
+ return (struct X){.a = a | c, .b = b | c};
+}
--
2.45.2
