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LoongArch: Optimize the loading of immediate numbers with the same high and low 32-bit values

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For the following immediate load operation in gcc/testsuite/gcc.target/loongarch/imm-load1.c:

	long long r = 0x0101010101010101;

Before this patch:

	lu12i.w	    $r15,16842752>>12
	ori	    $r15,$r15,257
	lu32i.d	    $r15,0x1010100000000>>32
	lu52i.d	    $r15,$r15,0x100000000000000>>52

After this patch:

	lu12i.w     $r15,16842752>>12
	ori         $r15,$r15,257
	bstrins.d   $r15,$r15,63,32

gcc/ChangeLog:

	* config/loongarch/loongarch.cc
	(enum loongarch_load_imm_method): Add new method.
	(loongarch_build_integer): Add relevant implementations for
	new method.
	(loongarch_move_integer): Ditto.

gcc/testsuite/ChangeLog:

	* gcc.target/loongarch/imm-load1.c: Change old check.
This commit is contained in:
Guo Jie 2023-11-23 11:04:17 +08:00 • committed by Lulu Cheng
parent df8dfd7837
commit 96577dfae9
2 changed files with 23 additions and 2 deletions
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22
gcc/config/loongarch/loongarch.cc
View file

@ -142,12 +142,16 @@ struct loongarch_address_info
METHOD_LU52I:
Load 52-63 bit of the immediate number.
METHOD_MIRROR:
Copy 0-31 bit of the immediate number to 32-63bit.
*/
enum loongarch_load_imm_method
{
METHOD_NORMAL,
METHOD_LU32I,
METHOD_LU52I
METHOD_LU52I,
METHOD_MIRROR
};
struct loongarch_integer_op
@ -1556,11 +1560,23 @@ loongarch_build_integer (struct loongarch_integer_op *codes,
int sign31 = (value & (HOST_WIDE_INT_1U << 31)) >> 31;
int sign51 = (value & (HOST_WIDE_INT_1U << 51)) >> 51;
uint32_t hival = (uint32_t) (value >> 32);
uint32_t loval = (uint32_t) value;
/* Determine whether the upper 32 bits are sign-extended from the lower
32 bits. If it is, the instructions to load the high order can be
ommitted. */
if (lu32i[sign31] && lu52i[sign31])
return cost;
/* If the lower 32 bits are the same as the upper 32 bits, just copy
the lower 32 bits to the upper 32 bits. */
else if (loval == hival)
{
codes[cost].method = METHOD_MIRROR;
codes[cost].curr_value = value;
return cost + 1;
}
/* Determine whether bits 32-51 are sign-extended from the lower 32
bits. If so, directly load 52-63 bits. */
else if (lu32i[sign31])
@ -3234,6 +3250,10 @@ loongarch_move_integer (rtx temp, rtx dest, unsigned HOST_WIDE_INT value)
gen_rtx_AND (DImode, x, GEN_INT (0xfffffffffffff)),
GEN_INT (codes[i].value));
break;
case METHOD_MIRROR:
gcc_assert (mode == DImode);
emit_insn (gen_insvdi (x, GEN_INT (32), GEN_INT (32), x));
break;
default:
gcc_unreachable ();
}

3
gcc/testsuite/gcc.target/loongarch/imm-load1.c
View file

@ -1,6 +1,7 @@
/* { dg-do compile } */
/* { dg-options "-mabi=lp64d -O2" } */
/* { dg-final { scan-assembler "test:.*lu52i\.d.*\n\taddi\.w.*\n\.L2:" } } */
/* { dg-final { scan-assembler-not "test:.*lu52i\.d.*\n\taddi\.w.*\n\.L2:" } } */
/* { dg-final { scan-assembler "test:.*lu12i\.w.*\n\tbstrins\.d.*\n\.L2:" } } */
extern long long b[10];