!!! tip "Tipp"

!!! tip

//go:build !faketime

#include "go_asm.h"
#include "textflag.h"
#include "time_windows.h"

TEXT time·now(SB),NOSPLIT,$0-20
loop:
	MOVL	(_INTERRUPT_TIME+time_hi1), AX
	MOVL	(_INTERRUPT_TIME+time_lo), CX
	MOVL	(_INTERRUPT_TIME+time_hi2), DI
	CMPL	AX, DI
	JNE	loop

	// w = DI:CX
	// multiply by 100
	MOVL	$100, AX
	MULL	CX
	IMULL	$100, DI
	ADDL	DI, DX
	// w*100 = DX:AX
	MOVL	AX, mono+12(FP)

loop: // test that labeled select can be inlined.
	select {
	case <-x:
		break loop
	case <-y:
	}
}

func inlineSelect2(x, y chan bool) { // ERROR "can inline inlineSelect2" ERROR "x does not escape" "y does not escape"
loop:
	for i := 0; i < 5; i++ {
		if i == 3 {
			break loop
		}
		select2(x, y) // ERROR "inlining call to select2"
	}

	HotPgoInitial          = HotPgo | HotInitial                // special case; single block loop, initial block is header block has a flow-in entry, but PGO says it is hot
	HotPgoInitialNotFLowIn = HotPgo | HotInitial | HotNotFlowIn // PGO says it is hot, and the loop is rotated so flow enters loop with a branch

	// make sure we don't get into an infinite loop with phi values.
	c := testConfig(t)
	ptrType := c.config.Types.BytePtr
	fun := c.Fun("entry",
		Bloc("entry",
			Valu("start", OpInitMem, types.TypeMem, 0, nil),
			Valu("sb", OpSB, c.config.Types.Uintptr, 0, nil),
			Valu("v", OpConstBool, c.config.Types.Bool, 1, nil),
			Valu("addr", OpAddr, ptrType, 0, nil, "sb"),
			Goto("loop")),
		Bloc("loop",

	c := make(chan bool)
	go func() {
		defer func() { c <- true }()
		C.msanGoLoop()
	}()

	for C.msanGoReady() == 0 {
		time.Sleep(time.Microsecond)
	}

loop:
	for {
		select {
		case <-c:
			break loop
		default:
			C.msanGoSendSignal()
			time.Sleep(time.Microsecond)
		}
	}

	// For each moveable value, record the block that dominates all uses found so far.
	target := f.Cache.allocBlockSlice(f.NumValues())
	defer f.Cache.freeBlockSlice(target)

	// Grab loop information.
	// We use this to make sure we don't tighten a value into a (deeper) loop.
	idom := f.Idom()
	loops := f.loopnest()
	loops.calculateDepths()

	changed := true
	for changed {
		changed = false

		// Reset target

	MOVQ 16(DI), R10 // h2
	MOVQ 24(DI), R11 // r0
	MOVQ 32(DI), R12 // r1

	CMPQ R15, $16
	JB   bytes_between_0_and_15

loop:
	POLY1305_ADD(SI, R8, R9, R10)

multiply:
	POLY1305_MUL(R8, R9, R10, R11, R12, BX, CX, R13, R14)
	SUBQ $16, R15
	CMPQ R15, $16
	JAE  loop

bytes_between_0_and_15:
	TESTQ R15, R15
	JZ    done
	MOVQ  $1, BX
	XORQ  CX, CX
	XORQ  R13, R13
	ADDQ  R15, SI

    loop.
  }];

  let description = [{
    More details can be found in Tensorflow Control Flow white paper:
    https://storage.googleapis.com/download.tensorflow.org/paper/white_paper_tf_control_flow_implementation_2017_11_1.pdf

    Each tensor needs its own tf_executor.Enter to be made available inside a
    while loop.

    This is defined in Tensorflow as: