From: Jan Hubicka <hubicka@ucw.cz>
Date: Tue, 15 Apr 2025 17:09:20 +0000 (+0200)
Subject: Set znver5 issue rate to 4.
X-Git-Tag: basepoints/gcc-16~57
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4a01869b963520d689fe9242cf2ff24984ea41d8;p=thirdparty%2Fgcc.git

Set znver5 issue rate to 4.

this patch sets issue rate of znver5 to 4.  With current model, unless a reservation is
missing, we will never issue more than 4 instructions per cycle since that is the limit
of decoders and the model does not take into acount the fact that typically code is run
from op cache.

gcc/ChangeLog:

	* config/i386/x86-tune-sched.cc (ix86_issue_rate): Set
	to 4 for znver5.
---

diff --git a/gcc/config/i386/x86-tune-sched.cc b/gcc/config/i386/x86-tune-sched.cc
index 685a83c4311..15d3d91a83b 100644
--- a/gcc/config/i386/x86-tune-sched.cc
+++ b/gcc/config/i386/x86-tune-sched.cc
@@ -81,6 +81,14 @@ ix86_issue_rate (void)
     case PROCESSOR_YONGFENG:
     case PROCESSOR_SHIJIDADAO:
     case PROCESSOR_GENERIC:
+    /* For znver5 decoder can handle 4 or 8 instructions per cycle,
+       op cache 12 instruction/cycle, dispatch 8 instructions
+       integer rename 8 instructions and Fp 6 instructions.
+
+       The scheduler, without understanding out of order nature of the CPU
+       is not going to be able to use more than 4 instructions since that
+       is limits of the decoders.  */
+    case PROCESSOR_ZNVER5:
       return 4;
 
     case PROCESSOR_ICELAKE_CLIENT:
@@ -91,13 +99,6 @@ ix86_issue_rate (void)
       return 5;
 
     case PROCESSOR_SAPPHIRERAPIDS:
-    /* For znver5 decoder can handle 4 or 8 instructions per cycle,
-       op cache 12 instruction/cycle, dispatch 8 instructions
-       integer rename 8 instructions and Fp 6 instructions.
-
-       The scheduler, without understanding out of order nature of the CPU
-       is unlikely going to be able to fill all of these.  */
-    case PROCESSOR_ZNVER5:
       return 6;
 
     default: