From: Wilco Dijkstra <wilco.dijkstra@arm.com>
Date: Wed, 17 Apr 2024 16:18:23 +0000 (+0100)
Subject: AArch64: Improve costing of ctz
X-Git-Tag: basepoints/gcc-16~8857
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e14c673ea9ab2eca5de4db91b478f0b5297ef321;p=thirdparty%2Fgcc.git

AArch64: Improve costing of ctz

Improve costing of ctz - both TARGET_CSSC and vector cases were not handled yet.

gcc:
	* config/aarch64/aarch64.cc (aarch64_rtx_costs): Improve CTZ costing.
---

diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index 662ff5a9b0c..ee12d8897a8 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -14349,10 +14349,24 @@ aarch64_rtx_costs (rtx x, machine_mode mode, int outer ATTRIBUTE_UNUSED,
       return false;
 
     case CTZ:
-      *cost = COSTS_N_INSNS (2);
-
-      if (speed)
-	*cost += extra_cost->alu.clz + extra_cost->alu.rev;
+      if (VECTOR_MODE_P (mode))
+	{
+	  *cost = COSTS_N_INSNS (3);
+	  if (speed)
+	    *cost += extra_cost->vect.alu * 3;
+	}
+      else if (TARGET_CSSC)
+	{
+	  *cost = COSTS_N_INSNS (1);
+	  if (speed)
+	    *cost += extra_cost->alu.clz;
+	}
+      else
+	{
+	  *cost = COSTS_N_INSNS (2);
+	  if (speed)
+	    *cost += extra_cost->alu.clz + extra_cost->alu.rev;
+	}
       return false;
 
     case COMPARE: