From: David Chase <drchase@google.com>
Date: Thu, 9 Oct 2025 18:39:59 +0000 (-0400)
Subject: [dev.simd] cmd/compile: more support for cpufeatures
X-Git-Tag: go1.26rc1~147^2~44
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=ba72ee0f308e1450fa18c4073b18275377671997;p=gostls13.git

[dev.simd] cmd/compile: more support for cpufeatures

add hasFeature, also record maximum feature for a function

Change-Id: I68dd063aad1c1dc0ef5310a9f5d970c03dd31a0e
Reviewed-on: https://go-review.googlesource.com/c/go/+/710695
Reviewed-by: Junyang Shao <shaojunyang@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
---

diff --git a/src/cmd/compile/internal/ssa/block.go b/src/cmd/compile/internal/ssa/block.go
index f457e66f16..0ed90b5a7f 100644
--- a/src/cmd/compile/internal/ssa/block.go
+++ b/src/cmd/compile/internal/ssa/block.go
@@ -473,6 +473,10 @@ const (
 	CPUsve2
 )
 
+func (f CPUfeatures) hasFeature(x CPUfeatures) bool {
+	return f&x == x
+}
+
 func (f CPUfeatures) String() string {
 	if f == CPUNone {
 		return "none"
diff --git a/src/cmd/compile/internal/ssa/cpufeatures.go b/src/cmd/compile/internal/ssa/cpufeatures.go
index 77b1db552d..e668958fab 100644
--- a/src/cmd/compile/internal/ssa/cpufeatures.go
+++ b/src/cmd/compile/internal/ssa/cpufeatures.go
@@ -201,6 +201,7 @@ func cpufeatures(f *Func) {
 		}
 
 		b.CPUfeatures = feat
+		f.maxCPUFeatures |= feat // not necessary to refine this estimate below
 	}
 
 	// If the flow graph is irreducible, things can still change on backedges.
diff --git a/src/cmd/compile/internal/ssa/func.go b/src/cmd/compile/internal/ssa/func.go
index 0f895e5018..4368252da4 100644
--- a/src/cmd/compile/internal/ssa/func.go
+++ b/src/cmd/compile/internal/ssa/func.go
@@ -41,6 +41,8 @@ type Func struct {
 	ABISelf        *abi.ABIConfig // ABI for function being compiled
 	ABIDefault     *abi.ABIConfig // ABI for rtcall and other no-parsed-signature/pragma functions.
 
+	maxCPUFeatures CPUfeatures // union of all the CPU features in all the blocks.
+
 	scheduled   bool  // Values in Blocks are in final order
 	laidout     bool  // Blocks are ordered
 	NoSplit     bool  // true if function is marked as nosplit.  Used by schedule check pass.