[dev.simd] all: merge master (ca37d24) into dev.simd

Conflicts:

- src/cmd/compile/internal/typecheck/builtin.go

Merge List:

+ 2025-11-20 ca37d24e0b net/http: drop unused "broken" field from persistConn
+ 2025-11-20 4b740af56a cmd/internal/obj/x86: handle global reference in From3 in dynlink mode
+ 2025-11-20 790384c6c2 spec: adjust rule for type parameter on RHS of alias declaration
+ 2025-11-20 a49b0302d0 net/http: correctly close fake net.Conns
+ 2025-11-20 32f5aadd2f cmd/compile: stack allocate backing stores during append
+ 2025-11-20 a18aff8057 runtime: select GC mark workers during start-the-world
+ 2025-11-20 829779f4fe runtime: split findRunnableGCWorker in two
+ 2025-11-20 ab59569099 go/version: use "custom" as an example of a version suffix
+ 2025-11-19 c4bb9653ba cmd/compile: Implement LoweredZeroLoop with LSX Instruction on loong64
+ 2025-11-19 7f2ae21fb4 cmd/internal/obj/loong64: add MULW.D.W[U] instructions
+ 2025-11-19 a2946f2385 crypto: add Encapsulator and Decapsulator interfaces
+ 2025-11-19 6b83bd7146 crypto/ecdh: add KeyExchanger interface
+ 2025-11-19 4fef9f8b55 go/types, types2: fix object path for grouped declaration statements
+ 2025-11-19 33529db142 spec: escape double-ampersands
+ 2025-11-19 dc42565a20 cmd/compile: fix control flow for unsigned divisions proof relations
+ 2025-11-19 e64023dcbf cmd/compile: cleanup useless if statement in prove
+ 2025-11-19 2239520d1c test: go fmt prove.go tests
+ 2025-11-19 489d3dafb7 math: switch s390x math.Pow to generic implementation
+ 2025-11-18 8c41a482f9 runtime: add dlog.hexdump
+ 2025-11-18 e912618bd2 runtime: add hexdumper
+ 2025-11-18 2cf9d4b62f Revert "net/http: do not discard body content when closing it within request handlers"
+ 2025-11-18 4d0658bb08 cmd/compile: prefer fixed registers for values
+ 2025-11-18 ba634ca5c7 cmd/compile: fold boolean NOT into branches
+ 2025-11-18 8806d53c10 cmd/link: align sections, not symbols after DWARF compress
+ 2025-11-18 c93766007d runtime: do not print recovered when double panic with the same value
+ 2025-11-18 9859b43643 cmd/asm,cmd/compile,cmd/internal/obj/riscv: use compressed instructions on riscv64
+ 2025-11-17 b9ef0633f6 cmd/internal/sys,internal/goarch,runtime: enable the use of compressed instructions on riscv64
+ 2025-11-17 a087dea869 debug/elf: sync new loong64 relocation types up to LoongArch ELF psABI v20250521
+ 2025-11-17 e1a12c781f cmd/compile: use 32x32->64 multiplies on arm64
+ 2025-11-17 6caab99026 runtime: relax TestMemoryLimit on darwin a bit more
+ 2025-11-17 eda2e8c683 runtime: clear frame pointer at thread entry points
+ 2025-11-17 6919858338 runtime: rename findrunnable references to findRunnable
+ 2025-11-17 8e734ec954 go/ast: fix BasicLit.End position for raw strings containing \r
+ 2025-11-17 592775ec7d crypto/mlkem: avoid a few unnecessary inverse NTT calls
+ 2025-11-17 590cf18daf crypto/mlkem/mlkemtest: add derandomized Encapsulate768/1024
+ 2025-11-17 c12c337099 cmd/compile: teach prove about subtract idioms
+ 2025-11-17 bc15963813 cmd/compile: clean up prove pass
+ 2025-11-17 1297fae708 go/token: add (*File).End method
+ 2025-11-17 65c09eafdf runtime: hoist invariant code out of heapBitsSmallForAddrInline
+ 2025-11-17 594129b80c internal/runtime/maps: update doc for table.Clear
+ 2025-11-15 c58d075e9a crypto/rsa: deprecate PKCS#1 v1.5 encryption
+ 2025-11-14 d55ecea9e5 runtime: usleep before stealing runnext only if not in syscall
+ 2025-11-14 410ef44f00 cmd: update x/tools to 59ff18c
+ 2025-11-14 50128a2154 runtime: support runtime.freegc in size-specialized mallocs for noscan objects
+ 2025-11-14 c3708350a4 cmd/go: tests: rename git-min-vers->git-sha256
+ 2025-11-14 aea881230d std: fix printf("%q", int) mistakes
+ 2025-11-14 120f1874ef runtime: add more precise test of assist credit handling for runtime.freegc
+ 2025-11-14 fecfcaa4f6 runtime: add runtime.freegc to reduce GC work
+ 2025-11-14 5a347b775e runtime: set GOEXPERIMENT=runtimefreegc to disabled by default
+ 2025-11-14 1a03d0db3f runtime: skip tests for GOEXPERIMENT=arenas that do not handle clobberfree=1
+ 2025-11-14 cb0d9980f5 net/http: do not discard body content when closing it within request handlers
+ 2025-11-14 03ed43988f cmd/compile: allow multi-field structs to be stored directly in interfaces
+ 2025-11-14 1bb1f2bf0c runtime: put AddCleanup cleanup arguments in their own allocation
+ 2025-11-14 9fd2e44439 runtime: add AddCleanup benchmark
+ 2025-11-14 80c91eedbb runtime: ensure weak handles end up in their own allocation
+ 2025-11-14 7a8d0b5d53 runtime: add debug mode to extend _Grunning-without-P windows
+ 2025-11-14 710abf74da internal/runtime/cgobench: add Go function call benchmark for comparison
+ 2025-11-14 b24aec598b doc, cmd/internal/obj/riscv: document the riscv64 assembler
+ 2025-11-14 a0e738c657 cmd/compile/internal: remove incorrect riscv64 SLTI rule
+ 2025-11-14 2cdcc4150b cmd/compile: fold negation into multiplication
+ 2025-11-14 b57962b7c7 bytes: fix panic in bytes.Buffer.Peek
+ 2025-11-14 0a569528ea cmd/compile: optimize comparisons with single bit difference
+ 2025-11-14 1e5e6663e9 cmd/compile: remove unnecessary casts and types from riscv64 rules
+ 2025-11-14 ddd8558e61 go/types, types2: swap object.color for Checker.objPathIdx
+ 2025-11-14 9daaab305c cmd/link/internal/ld: make runtime.buildVersion with experiments valid
+ 2025-11-13 d50a571ddf test: fix tests to work with sizespecializedmalloc turned off
+ 2025-11-13 704f841eab cmd/trace: annotation proc start/stop with thread and proc always
+ 2025-11-13 17a02b9106 net/http: remove unused isLitOrSingle and isNotToken
+ 2025-11-13 ff61991aed cmd/go: fix flaky TestScript/mod_get_direct
+ 2025-11-13 129d0cb543 net/http/cgi: accept INCLUDED as protocol for server side includes
+ 2025-11-13 77c5130100 go/types: minor simplification
+ 2025-11-13 7601cd3880 go/types: generate cycles.go
+ 2025-11-13 7a372affd9 go/types, types2: rename definedType to declaredType and clarify docs

Change-Id: Ibaa9bdb982364892f80e511c1bb12661fcd5fb86

3 files changed, 122 insertions, 2 deletions

diff --git a/src/runtime/testdata/testprog/crash.go b/src/runtime/testdata/testprog/crash.go
index 556215a71e..fcce388871 100644
--- a/src/runtime/testdata/testprog/crash.go
+++ b/src/runtime/testdata/testprog/crash.go
@@ -22,6 +22,7 @@ func init() {
 	register("RepanickedPanic", RepanickedPanic)
 	register("RepanickedMiddlePanic", RepanickedMiddlePanic)
 	register("RepanickedPanicSandwich", RepanickedPanicSandwich)
+	register("DoublePanicWithSameValue", DoublePanicWithSameValue)
 }
 
 func test(name string) {
@@ -189,3 +190,13 @@ func RepanickedPanicSandwich() {
 		panic("outer")
 	}()
 }
+
+// Double panic with same value and not recovered.
+// See issue 76099.
+func DoublePanicWithSameValue() {
+	var e any = "message"
+	defer func() {
+		panic(e)
+	}()
+	panic(e)
+}
diff --git a/src/runtime/testdata/testprog/gc.go b/src/runtime/testdata/testprog/gc.go
index bbe1453401..32e2c5e1b4 100644
--- a/src/runtime/testdata/testprog/gc.go
+++ b/src/runtime/testdata/testprog/gc.go
@@ -396,7 +396,7 @@ func gcMemoryLimit(gcPercent int) {
 		// should do considerably better than this bound.
 		bound := int64(myLimit + 16<<20)
 		if runtime.GOOS == "darwin" {
-			bound += 16 << 20 // Be more lax on Darwin, see issue 73136.
+			bound += 24 << 20 // Be more lax on Darwin, see issue 73136.
 		}
 		start := time.Now()
 		for time.Since(start) < 200*time.Millisecond {
diff --git a/src/runtime/testdata/testprog/stw_trace.go b/src/runtime/testdata/testprog/stw_trace.go
index 0fed55b875..0fa15da09e 100644
--- a/src/runtime/testdata/testprog/stw_trace.go
+++ b/src/runtime/testdata/testprog/stw_trace.go
@@ -7,15 +7,18 @@ package main
 import (
 	"context"
 	"log"
+	"math/rand/v2"
 	"os"
 	"runtime"
 	"runtime/debug"
+	"runtime/metrics"
 	"runtime/trace"
 	"sync/atomic"
 )
 
 func init() {
 	register("TraceSTW", TraceSTW)
+	register("TraceGCSTW", TraceGCSTW)
 }
 
 // The parent writes to ping and waits for the children to write back
@@ -53,7 +56,7 @@ func TraceSTW() {
 	// https://go.dev/issue/65694). Alternatively, we could just ignore the
 	// trace if the GC runs.
 	runtime.GOMAXPROCS(4)
-	debug.SetGCPercent(0)
+	debug.SetGCPercent(-1)
 
 	if err := trace.Start(os.Stdout); err != nil {
 		log.Fatalf("failed to start tracing: %v", err)
@@ -86,6 +89,112 @@ func TraceSTW() {
 	stop.Store(true)
 }
 
+// Variant of TraceSTW for GC STWs. We want the GC mark workers to start on
+// previously-idle Ps, rather than bumping the current P.
+func TraceGCSTW() {
+	ctx := context.Background()
+
+	// The idea here is to have 2 target goroutines that are constantly
+	// running. When the world restarts after STW, we expect these
+	// goroutines to continue execution on the same M and P.
+	//
+	// Set GOMAXPROCS=8 to make room for the 2 target goroutines, 1 parent,
+	// 2 dedicated workers, and a bit of slack.
+	//
+	// Disable the GC initially so we can be sure it only triggers once we
+	// are ready.
+	runtime.GOMAXPROCS(8)
+	debug.SetGCPercent(-1)
+
+	if err := trace.Start(os.Stdout); err != nil {
+		log.Fatalf("failed to start tracing: %v", err)
+	}
+	defer trace.Stop()
+
+	for i := range 2 {
+		go traceSTWTarget(i)
+	}
+
+	// Wait for children to start running.
+	ping.Store(1)
+	for pong[0].Load() != 1 {}
+	for pong[1].Load() != 1 {}
+
+	trace.Log(ctx, "TraceSTW", "start")
+
+	// STW
+	triggerGC()
+
+	// Make sure to run long enough for the children to schedule again
+	// after STW. This is included for good measure, but the goroutines
+	// really ought to have already scheduled since the entire GC
+	// completed.
+	ping.Store(2)
+	for pong[0].Load() != 2 {}
+	for pong[1].Load() != 2 {}
+
+	trace.Log(ctx, "TraceSTW", "end")
+
+	stop.Store(true)
+}
+
+func triggerGC() {
+	// Allocate a bunch to trigger the GC rather than using runtime.GC. The
+	// latter blocks until the GC is complete, which is convenient, but
+	// messes with scheduling as it gives this P a chance to steal the
+	// other goroutines before their Ps get up and running again.
+
+	// Bring heap size up prior to enabling the GC to ensure that there is
+	// a decent amount of work in case the GC triggers immediately upon
+	// re-enabling.
+	for range 1000 {
+		alloc()
+	}
+
+	sample := make([]metrics.Sample, 1)
+	sample[0].Name = "/gc/cycles/total:gc-cycles"
+	metrics.Read(sample)
+
+	start := sample[0].Value.Uint64()
+
+	debug.SetGCPercent(100)
+
+	// Keep allocating until the GC is complete. We really only need to
+	// continue until the mark workers are scheduled, but there isn't a
+	// good way to measure that.
+	for {
+		metrics.Read(sample)
+		if sample[0].Value.Uint64() != start {
+			return
+		}
+
+		alloc()
+	}
+}
+
+// Allocate a tree data structure to generate plenty of scan work for the GC.
+
+type node struct {
+	children []*node
+}
+
+var gcSink node
+
+func alloc() {
+	// 10% chance of adding a node a each layer.
+
+	curr := &gcSink
+	for {
+		if len(curr.children) == 0 || rand.Float32() < 0.1 {
+			curr.children = append(curr.children, new(node))
+			return
+		}
+
+		i := rand.IntN(len(curr.children))
+		curr = curr.children[i]
+	}
+}
+
 // Manually insert a morestack call. Leaf functions can omit morestack, but
 // non-leaf functions should include them.