identifiers not by parsing C code but by feeding carefully constructed
programs into the system C compiler and interpreting the generated
error messages, debug information, and object files. In practice,
parsing these is significantly less work and more robust than parsing
C source.

Cgo first invokes gcc -E -dM on the preamble, in order to find out
about simple #defines for constants and the like. These are recorded
for later use.

	instructions["JL"] = x86.AJLT   /* alternate */
	instructions["JLE"] = x86.AJLE  /* less than or equal (signed) (ZF = 1 || SF != OF) */
	instructions["JLO"] = x86.AJCS  /* alternate */
	instructions["JLS"] = x86.AJLS  /* lower or same (unsigned) (CF = 1 || ZF = 1) */
	instructions["JLT"] = x86.AJLT  /* less than (signed) (SF != OF) */
	instructions["JMI"] = x86.AJMI  /* negative (minus) (SF = 1) */

and not yet overwritten.
These implementation constraints make Go more like Java or JavaScript,
in that most races have a limited number of outcomes,
and less like C and C++, where the meaning of any program with a race
is entirely undefined, and the compiler may do anything at all.
Go's approach aims to make errant programs more reliable and easier to debug,

		return false
	}
	// R1<<...
	if lex.IsRegisterShift(p.peek()) {
		return true
	}
	// R(1)<<...   Ugly check. TODO: Rethink how we handle ARM register shifts to be
	// less special.
	if p.peek() != '(' || len(p.input)-p.inputPos < 4 {
		return false
	}
	return p.at('(', scanner.Int, ')') && lex.IsRegisterShift(p.input[p.inputPos+3].ScanToken)
}

	// abc
	// abc
	// dbc
}

func ExampleCompare() {
	// Interpret Compare's result by comparing it to zero.
	var a, b []byte
	if bytes.Compare(a, b) < 0 {
		// a less b
	}
	if bytes.Compare(a, b) <= 0 {
		// a less or equal b
	}
	if bytes.Compare(a, b) > 0 {
		// a greater b
	}
	if bytes.Compare(a, b) >= 0 {
		// a greater or equal b
	}

		if sr.pos >= holeEnd && len(sr.sp) > 1 {
			sr.sp = sr.sp[1:] // Ensure last fragment always remains
		}
	}

	n = len(b0) - len(b)
	switch {
	case err == io.EOF:
		return n, errMissData // Less data in dense file than sparse file
	case err != nil:
		return n, err
	case sr.logicalRemaining() == 0 && sr.physicalRemaining() > 0:
		return n, errUnrefData // More data in dense file than sparse file
	case finished:

	FMSUBS	F1, F2, F3, F4				// 47822018
	FNMSUBS	F1, F2, F3, F4				// 4b822018
	FNMADDS	F1, F2, F3, F4				// 4f822018

	// 20.8: Single-Precision Floating-Point Compare Instructions
	FEQS	F0, F1, X7				// d3a300a0
	FLTS	F0, F1, X7				// d39300a0
	FLES	F0, F1, X7				// d38300a0

	// 20.9: Single-Precision Floating-Point Classify Instruction
	FCLASSS	F0, X5					// d31200e0