From: Lulu Cheng <chenglulu@loongson.cn>
Date: Sun, 25 May 2025 03:15:07 +0000 (+0800)
Subject: LoongArch: Optimize normal immediate data loading.
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=abb22d046d3ee0b6a6ae2922bdd354e65096d8ca;p=thirdparty%2Fgcc.git

LoongArch: Optimize normal immediate data loading.

Ensure that only one register is used when loading immediate values.
The original immediate value load is handled through virtual
registers, resulting in the following load operation
(0x1234567890abcdef):
        lu12i.w $r4,-456004                     # 0xfffffffffff90abc
        or      $r12,$r0,$r0
        ori     $r4,$r4,3567
        lu32i.d $r12,0x45678
        lu32i.d $r4,0
        or      $r4,$r4,$r12
        lu52i.d $r4,$r4,0x123

The optimized sequence is as follows:
	lu12i.w	$r4,-456004			# 0xfffffffffff90abc
	ori	$r4,$r4,3567
	lu32i.d	$r4,0x45678
	lu52i.d	$r4,$r4,0x123

gcc/ChangeLog:

	* config/loongarch/loongarch.cc (loongarch_move_integer):
	No new virtual register is allocated during immediate load.

gcc/testsuite/ChangeLog:

	* gcc.target/loongarch/imm-load.c: Modify.
---

diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
index 1dce56e46fd..c725d028d8c 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -3439,13 +3439,8 @@ loongarch_move_integer (rtx temp, rtx dest, unsigned HOST_WIDE_INT value)
   x = GEN_INT (codes[0].value);
   for (i = 1; i < num_ops; i++)
     {
-      if (!can_create_pseudo_p ())
-	{
-	  emit_insn (gen_rtx_SET (temp, x));
-	  x = temp;
-	}
-      else
-	x = force_reg (mode, x);
+      emit_insn (gen_rtx_SET (temp, x));
+      x = temp;
 
       set_unique_reg_note (get_last_insn (), REG_EQUAL,
 			   GEN_INT (codes[i-1].curr_value));
diff --git a/gcc/testsuite/gcc.target/loongarch/imm-load.c b/gcc/testsuite/gcc.target/loongarch/imm-load.c
index 33291fe89bd..a125840d507 100644
--- a/gcc/testsuite/gcc.target/loongarch/imm-load.c
+++ b/gcc/testsuite/gcc.target/loongarch/imm-load.c
@@ -7,5 +7,5 @@ test (void)
 {
   return 0x1234567890abcdef;
 }
-/* { dg-final { scan-rtl-dump-times "scanning new insn with uid" 6 "split1" } } */
+/* { dg-final { scan-rtl-dump-times "scanning new insn with uid" 4 "split1" } } */