[PATCH]rs6000: Update rtx_cost for constant building

[PATCH]rs6000: Update rtx_cost for constant building

[Jiufu Guo]

When building a const to a reg, it may need a few instructions.
This patch updates rs6000_rtx_costs to make it more accurate for
constant building.

With this patch, cse.cc could get accurate cost for complex
constant and then read the constant from a pool.
As discussed in the mail list, this patch is updating rtx_cost hook
which may be preferred for this issue.

Bootstrap and regtest pass on ppc64 and ppc64le.
Is this ok for trunk or more suitable for stage1?


BR,
Jiufu

	PR target/63281

gcc/ChangeLog:

	* config/rs6000/rs6000.cc (rs6000_rtx_costs): Update for
	const int.

gcc/testsuite/ChangeLog:

	* gcc.target/powerpc/pr63281.c: New test.

---
 gcc/config/rs6000/rs6000.cc                |  8 ++++++++
 gcc/testsuite/gcc.target/powerpc/pr63281.c | 11 +++++++++++
 2 files changed, 19 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr63281.c

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 283e8306ff7..62fcd345af2 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -21838,6 +21838,14 @@ rs6000_rtx_costs (rtx x, machine_mode mode, int outer_code,
 
     case CONST_DOUBLE:
     case CONST_WIDE_INT:
+      /* Set a const to reg, it may needs a few insns.  */
+      if (outer_code == SET)
+	{
+	  *total = COSTS_N_INSNS (num_insns_constant (x, mode));
+	  return true;
+	}
+      /* FALLTHRU */
+
     case CONST:
     case HIGH:
     case SYMBOL_REF:
diff --git a/gcc/testsuite/gcc.target/powerpc/pr63281.c b/gcc/testsuite/gcc.target/powerpc/pr63281.c
new file mode 100644
index 00000000000..469a8f64400
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr63281.c
@@ -0,0 +1,11 @@
+/* PR target/63281 */
+/* { dg-do compile { target lp64 } } */
+/* { dg-options "-O2 -std=c99" } */
+
+void
+foo (unsigned long long *a)
+{
+  *a = 0x020805006106003;
+}
+
+/* { dg-final { scan-assembler-times {\mp?ld\M} 1 } } */
-- 
2.25.1