From: Martin Möhrmann <martin@golang.org>
Date: Sat, 24 Oct 2020 03:54:46 +0000 (+0200)
Subject: runtime: remove unused cpu architecture feature variables from binaries
X-Git-Tag: go1.18beta1~1672
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=c1a14781ec;p=gostls13.git

runtime: remove unused cpu architecture feature variables from binaries

On amd64 this reduces go binary sizes by 176 bytes due to not referencing
internal/cpu.ARM64 and internal/cpu.ARM.

Change-Id: I8e4f31e2b1939b05eec2148b44d7cff7e0aeb30e
Reviewed-on: https://go-review.googlesource.com/c/go/+/344329
Trust: Martin Möhrmann <martin@golang.org>
Run-TryBot: Martin Möhrmann <martin@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
---

diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index c2e43ef5c3..55023e3f9f 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -622,13 +622,18 @@ func cpuinit() {
 
 	// Support cpu feature variables are used in code generated by the compiler
 	// to guard execution of instructions that can not be assumed to be always supported.
-	x86HasPOPCNT = cpu.X86.HasPOPCNT
-	x86HasSSE41 = cpu.X86.HasSSE41
-	x86HasFMA = cpu.X86.HasFMA
+	switch GOARCH {
+	case "386", "AMD64":
+		x86HasPOPCNT = cpu.X86.HasPOPCNT
+		x86HasSSE41 = cpu.X86.HasSSE41
+		x86HasFMA = cpu.X86.HasFMA
 
-	armHasVFPv4 = cpu.ARM.HasVFPv4
+	case "arm":
+		armHasVFPv4 = cpu.ARM.HasVFPv4
 
-	arm64HasATOMICS = cpu.ARM64.HasATOMICS
+	case "arm64":
+		arm64HasATOMICS = cpu.ARM64.HasATOMICS
+	}
 }
 
 // The bootstrap sequence is: