GNU Compiler Collection

https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/
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### Initialize global variables using +initialize

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Executing-code-before-main.html

An example showing the problematic approach of using +initialize for global variable setup, which may occur too late.

```objective-c

FileStream *Stdin = nil;
FileStream *Stdout = nil;
FileStream *Stderr = nil;

@implementation FileStream

+ (void)initialize
{
    Stdin = [[FileStream new] initWithFd:0];
    Stdout = [[FileStream new] initWithFd:1];
    Stderr = [[FileStream new] initWithFd:2];
}

/* Other methods here */
@end


```

--------------------------------

### Insert Bits Examples

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/AVR-Built-in-Functions.html

Examples demonstrating how to use __builtin_avr_insert_bits to manipulate bit fields and port layouts.

```c
// same as val, bits is unused
__builtin_avr_insert_bits (0xffffffff, bits, val);
```

```c
// same as bits, val is unused
__builtin_avr_insert_bits (0x76543210, bits, val);
```

```c
// same as rotating bits by 4
__builtin_avr_insert_bits (0x32107654, bits, 0);
```

```c
// high nibble of result is the high nibble of val
// low nibble of result is the low nibble of bits
__builtin_avr_insert_bits (0xffff3210, bits, val);
```

```c
// reverse the bit order of bits
__builtin_avr_insert_bits (0x01234567, bits, 0);
```

--------------------------------

### Compile with command-line option

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/LoongArch-Attributes.html

Command-line example demonstrating how to disable lasx via command-line options.

```bash
$ gcc test.c -o test.s -O2 -mlasx -mno-lasx
```

--------------------------------

### Compile with target attribute

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/LoongArch-Attributes.html

Command-line example for compiling the test.c file with the WITH_ATTR macro defined.

```bash
$ gcc test.c -o test.s -O2 -mlasx -DWITH_ATTR
```

--------------------------------

### Define structures with zero-length bit-field alignment

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/x86-Options.html

Examples demonstrating how zero-length bit-fields affect the alignment and size of subsequent structure members.

```c
struct
 {
   char foo : 4;
   short : 0;
   char bar;
 } t2;

struct
 {
   char foo : 4;
   short : 0;
   double bar;
 } t3;
```

--------------------------------

### Define structure with trailing zero-length bit-field

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/x86-Options.html

Example showing how a zero-length bit-field can affect the alignment of the entire structure.

```c
struct
 {
   char foo : 6;
   long : 0;
 } t4;
```

--------------------------------

### Declare a structure for compound literal examples

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Compound-Literals.html

Defines the structure used in subsequent examples.

```c
struct foo {int a; char b[2];} structure;
```

--------------------------------

### Initialize EIND in .init3 section

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/AVR-Options.html

Example of setting the EIND register early in the startup sequence using a naked function in the .init3 section.

```c
#include <avr/io.h>

static void
__attribute__((section(".init3"),naked,used,no_instrument_function))
init3_set_eind (void)
{
  __asm volatile ("ldi r24,pm_hh8(__trampolines_start)\n\t"
                  "out %i0,r24" :: "n" (&EIND) : "r24","memory");
}
```

--------------------------------

### Define structure with zero-length bit-field

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/x86-Options.html

Example of using a zero-length bit-field to prevent coalescing of adjacent bit-fields.

```c
struct
 {
   unsigned long bf_1 : 12;
   unsigned long : 0;
   unsigned long bf_2 : 12;
 } t1;
```

--------------------------------

### Example of --prime-paths-lines output

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Invoking-Gcov.html

Sample output showing path coverage statistics and instructions for covering specific paths.

```text
paths covered 12 of 15
path  2 not covered: lines 8 8(false) 11(true) 11 13(true) 13(true) 14 17
path  3 not covered: lines 8 8(false) 11(true) 11 13(true) 13(false) 16 17
path  4 not covered: lines 8 8(false) 11(true) 11 13(false) 16 17
```

--------------------------------

### Conditional Branching Example

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Directly-mapped-SX-Builtin-Functions.html

Example usage of __lsx_bz_v for conditional branching based on vector state.

```c
  #include <lsxintrin.h>

  extern __m128i a;

  void
  test (void)
  {
    if (__lsx_bz_v (a))
      printf ("1\n");
    else
      printf ("2\n");
  }
```

--------------------------------

### Initializing Static Storage with __memx

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Named-Address-Spaces.html

Shows how to initialize a static pointer variable with a 24-bit address using the __memx address space.

```C
extern const __memx char foo;
const __memx void *pfoo = &foo;
```

--------------------------------

### Zero-Check Intrinsics Usage Example

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Directly-mapped-ASX-Builtin-Functions.html

Example demonstrating the use of the __lasx_xbz_v intrinsic for conditional branching.

```c
eg:
  #include <lasxintrin.h>

  extern __m256i a;

  void
  test (void)
  {
    if (__lasx_xbz_v (a))
      printf ("1\n");
    else
      printf ("2\n");
  }
```

--------------------------------

### Zero-Length Array Initialization Examples

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Zero-Length.html

Demonstrates valid and invalid initialization patterns for structures containing zero-length arrays.

```c
struct foo { int x; int y[]; };
struct bar { struct foo z; };

struct foo a = { 1, { 2, 3, 4 } };        // Valid.
struct bar b = { { 1, { 2, 3, 4 } } };    // Invalid.
struct bar c = { { 1, { } } };            // Valid.
struct foo d[1] = { { 1, { 2, 3, 4 } } };  // Invalid.
```

--------------------------------

### Dangling reference examples

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/C_002b_002b-Dialect-Options.html

Examples of code that triggers -Wdangling-reference warnings due to temporary lifetime issues.

```cpp
int n = 1;
const int& r = std::max(n - 1, n + 1); // r is dangling
```

```cpp
const int& f(const int& i) { return i; }
struct S {
  const int &r; // r is dangling
  S() : r(f(10)) { }
};
```

```cpp
struct S {
   const S& self () { return *this; }
};
const S& s = S().self(); // s is dangling
```

```cpp
auto p = std::minmax(1, 2);
```

--------------------------------

### Loop Distribution Transformation Example

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Optimize-Options.html

Demonstrates how loop distribution splits a single loop body into multiple loops to improve cache performance.

```Fortran
DO I = 1, N
  A(I) = B(I) + C
  D(I) = E(I) * F
ENDDO
```

```Fortran
DO I = 1, N
   A(I) = B(I) + C
ENDDO
DO I = 1, N
   D(I) = E(I) * F
ENDDO
```

--------------------------------

### x86 Assembler Dialect Example

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Extended-Asm.html

An example showing how dialect-specific instructions are expanded based on the target assembler dialect.

```asm
"bt{l %[Offset],%[Base] | %[Base],%[Offset]}; jc %l2"
```

```asm
"btl %[Offset],%[Base] ; jc %l2"   /* att dialect */
"bt %[Base],%[Offset]; jc %l2"     /* intel dialect */
```

--------------------------------

### Compile an Objective-C file

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Objective-C-and-Objective-C_002b_002b-Dialect-Options.html

Example command for compiling an Objective-C source file using the GNU runtime.

```bash
gcc -g -fgnu-runtime -O -c some_class.m
```

--------------------------------

### HP-UX assembler warning example

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Interoperation.html

Example of a warning message emitted by the HP-UX assembler when processing GCC-compiled code.

```text
(warning) Use of GR3 when
  frame >= 8192 may cause conflict.
```

--------------------------------

### Demonstrating __FUNCTION__ and __PRETTY_FUNCTION__ in C++

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Function-Names.html

Example showing the difference between __FUNCTION__ and __PRETTY_FUNCTION__ within a class method.

```cpp
extern "C" int printf (const char *, ...);

class a {
 public:
  void sub (int i)
    {
      printf ("__FUNCTION__ = %s\n", __FUNCTION__);
      printf ("__PRETTY_FUNCTION__ = %s\n", __PRETTY_FUNCTION__);
    }
};

int
main (void)
{
  a ax;
  ax.sub (0);
  return 0;
}
```

--------------------------------

### Mask Rotation Examples

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/AVR-Built-in-Functions.html

Examples showing how __builtin_avr_mask1 provides an efficient alternative to standard bitwise shift expressions.

```c
__builtin_avr_mask1 (1, offs)      // same like  1 << offs
__builtin_avr_mask1 (~1, offs)     // same like  ~(1 << offs)
__builtin_avr_mask1 (0x80, offs)   // same like  0x80 >> offs
__builtin_avr_mask1 (~0x80, offs)  // same like  ~(0x80 >> offs)
```

--------------------------------

### Loop Distribution Pattern Transformation Example

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Optimize-Options.html

Shows how loop distribution identifies patterns like initialization loops and replaces them with library calls such as memset.

```Fortran
DO I = 1, N
  A(I) = 0
  B(I) = A(I) + I
ENDDO
```

```Fortran
DO I = 1, N
   A(I) = 0
ENDDO
DO I = 1, N
   B(I) = A(I) + I
ENDDO
```

--------------------------------

### Intent Operand Usage Example

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Directly-mapped-SX-Builtin-Functions.html

Example showing that the first parameter is used as the intent operand when modifying part of a bitfield.

```c
  #include <lsxintrin.h>

  extern __m128i dst;
  extern int src;

  void
  test (void)
  {
    dst = __lsx_vinsgr2vr_b (dst, src, 3);
  }
```

--------------------------------

### Compile and Link with LTO

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Optimize-Options.html

Demonstrates the standard workflow for using link-time optimization by specifying flags during both compilation and linking stages.

```bash
gcc -c -O2 -flto foo.c
gcc -c -O2 -flto bar.c
gcc -o myprog -flto -O2 foo.o bar.o
```

--------------------------------

### Intent Operand Intrinsics Usage Example

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Directly-mapped-ASX-Builtin-Functions.html

Example showing how to use intrinsics where the first parameter serves as the intent operand.

```c
eg:
  #include <lasxintrin.h>
  extern __m256i dst;
  int src;

  void
  test (void)
  {
    dst = __lasx_xvinsgr2vr_w (dst, src, 3);
  }
```

--------------------------------

### Loop Optimization Example

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Non-bugs.html

An example of a loop that GCC may remove entirely if the expression does not affect global state and the result is unused.

```c
{
   int sum = 0;
   int ix;

   for (ix = 0; ix != 10000; ix++)
      sum += some_expression;
}
```

--------------------------------

### Defining Multiple Alternative Constraints

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Multi-Alternative.html

Example showing how to combine multiple alternatives for output and input operands using comma-separated constraint strings.

```c
"+m,r" (output) : "ir,irm" (input)
```

--------------------------------

### Example of machine-parseable fix-it hints

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Diagnostic-Message-Formatting-Options.html

Format of fix-it hints emitted for IDE consumption, showing the replacement range and string.

```text
fix-it:"test.c":{45:3-45:21}:"gtk_widget_show_all"
```

```text
00000000011111111112222222222
12345678901234567890123456789
  gtk_widget_showall (dlg);
  ^^^^^^^^^^^^^^^^^^
  gtk_widget_show_all
```

--------------------------------

### Redundant std::move warning examples

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/C_002b_002b-Dialect-Options.html

Examples demonstrating scenarios where std::move is redundant due to compiler-enforced rvalue treatment.

```cpp
struct T {
…
};
T fn(T t)
{
  …
  return std::move (t);
}
```

```cpp
struct T { // convertible to U
…
};
struct U {
…
};
U fn()
{
  T t;
  …
  return std::move (t);
}
```

--------------------------------

### Diagnostic Escape Format Examples

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Diagnostic-Message-Formatting-Options.html

Examples showing how different escape formats represent non-printable ASCII characters in source lines.

```text
 before<U+03C0><BF>after
```

```text
 before<CF><80><BF>after
```

--------------------------------

### Interactive Mode Startup Notice Template

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Copying.html

Short notice to display when a program starts in interactive mode to inform users of license terms and warranty status.

```text
program Copyright (C) year name of author 
This program comes with ABSOLUTELY NO WARRANTY; for details type ‘show w’.
This is free software, and you are welcome to redistribute it
under certain conditions; type ‘show c’ for details.
```

--------------------------------

### Infinite Loop Detection Example

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Static-Analyzer-Options.html

Example of code structure that triggers an infinite loop warning due to an implicit default case in a switch statement.

```c
  while (1)
    {
      char opcode = *cpu_state.pc;
      switch (opcode)
       {
       case OPCODE_FOO:
         handle_opcode_foo (&cpu_state);
         break;
       case OPCODE_BAR:
         handle_opcode_bar (&cpu_state);
         break;
       }
    }
```

--------------------------------

### Display Predefined Macros

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Preprocessor-Options.html

Example command to list all macros defined during preprocessor execution using the -dM flag.

```bash
touch foo.h; cpp -dM foo.h
```

--------------------------------

### Example of --prime-paths-source output

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Invoking-Gcov.html

Sample output providing a detailed breakdown of basic blocks and line numbers for uncovered paths.

```text
path 10 not covered:
BB  3:           8:  for (i = 0; i < 10; i++)
BB  3:           9:    total += i;
BB  4: (false)   8:  for (i = 0; i < 10; i++)
BB  5: (true)   11:  int v = total > 100 ? 1 : 2;
BB  6:          11:  int v = total > 100 ? 1 : 2;
BB  8: (false)  13:  if (total != 45 && v == 1)
BB 11:          16:    printf ("Success\n");
BB 12:          17:  return 0;
```

--------------------------------

### x86 Floating-Point asm Operand Examples

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Extended-Asm.html

Examples demonstrating the use of stack-like registers, early-clobber modifiers, and clobbering for stack management in x86 asm.

```c
asm ("foo" : "=t" (a) : "f" (b));
```

```c
asm ("foo" : "=&t" (a) : "f" (b));
```

```c
asm ("fsincos" : "=t" (cos), "=u" (sin) : "0" (inp));
```

```c
asm ("fyl2xp1" : "=t" (result) : "0" (x), "u" (y) : "st(1)");
```

--------------------------------

### __builtin_tbeginc

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/S_002f390-System-z-Built-in-Functions.html

Starts a constrained hardware transaction.

```APIDOC
## void __builtin_tbeginc(void)

### Description
Generates the tbeginc machine instruction starting a constrained hardware transaction.
```

--------------------------------

### Configure Offload Target Options

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/OpenMP-and-OpenACC-Options.html

Examples of passing specific compiler options to offload targets, either globally or for specific target architectures.

```bash
-foffload-options='-fno-math-errno -ffinite-math-only' \
        -foffload-options=nvptx-none=-latomic
-foffload-options=amdgcn-amdhsa=-march=gfx906
```

--------------------------------

### Vector Type Encoding

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Type-encoding.html

Example of encoding a vector type with a specified size.

```Objective-C
int a __attribute__ ((vector_size (16)));
```

--------------------------------

### Dump profiling information in freestanding environments

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Instrumentation-Options.html

Example C code demonstrating how to access and dump profiling information registered in a linker set for embedded systems.

```c
#include <gcov.h>
#include <stdio.h>
#include <stdlib.h>

extern const struct gcov_info *const __gcov_info_start[];
extern const struct gcov_info *const __gcov_info_end[];

static void
dump (const void *d, unsigned n, void *arg)
{
  const unsigned char *c = d;

  for (unsigned i = 0; i < n; ++i)
    printf ("%02x", c[i]);
}

static void
filename (const char *f, void *arg)
{
  __gcov_filename_to_gcfn (f, dump, arg );
}

static void *
allocate (unsigned length, void *arg)
{
  return malloc (length);
}

static void
dump_gcov_info (void)
{
  const struct gcov_info *const *info = __gcov_info_start;
  const struct gcov_info *const *end = __gcov_info_end;

  /* Obfuscate variable to prevent compiler optimizations.  */
  __asm__ ("" : "+r" (info));

  while (info != end)
  {
    void *arg = NULL;
    __gcov_info_to_gcda (*info, filename, dump, allocate, arg);
    putchar ('\n');
    ++info;
  }
}

int
main (void)
{
  dump_gcov_info ();
  return 0;
}
```

--------------------------------

### Array Type Encoding

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Type-encoding.html

Example of encoding an integer array of size 10.

```Objective-C
int a[10];
```

--------------------------------

### Sample gcov output file

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Invoking-Gcov.html

An example of the contents of a generated .gcov file.

```text
        -:    0:Source:tmp.cpp
        -:    0:Working directory:/home/gcc/testcase
        -:    0:Graph:tmp.gcno
        -:    0:Data:tmp.gcda
        -:    0:Runs:1
        -:    0:Programs:1
        -:    1:#include <stdio.h>
        -:    2:
        -:    3:template<class T>
        -:    4:class Foo
        -:    5:{
        -:    6:  public:
       1*:    7:  Foo(): b (1000) {}
------------------
Foo<char>::Foo():
    #####:    7:  Foo(): b (1000) {}
------------------
Foo<int>::Foo():
        1:    7:  Foo(): b (1000) {}
------------------
       2*:    8:  void inc () { b++; }
------------------
Foo<char>::inc():
    #####:    8:  void inc () { b++; }
------------------
Foo<int>::inc():
        2:    8:  void inc () { b++; }
------------------
        -:    9:
        -:   10:  private:
        -:   11:  int b;
        -:   12:};
        -:   13:
        -:   14:template class Foo<int>;
        -:   15:template class Foo<char>;
        -:   16:
        -:   17:int
        1:   18:main (void)
        -:   19:{
        -:   20:  int i, total;
        1:   21:  Foo<int> counter;
        -:   22:
        1:   23:  counter.inc();
        1:   24:  counter.inc();
        1:   25:  total = 0;
        -:   26:
       11:   27:  for (i = 0; i < 10; i++)
       10:   28:    total += i;
        -:   29:
       1*:   30:  int v = total > 100 ? 1 : 2;
        -:   31:
        1:   32:  if (total != 45)
    #####:   33:    printf ("Failure\n");
        -:   34:  else
        1:   35:    printf ("Success\n");
        1:   36:  return 0;
        -:   37:}
```

--------------------------------

### Example C source file for assembly generation

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Code-Gen-Options.html

A simple C function used to demonstrate the effect of assembly generation options.

```c
int test (int n)
{
  int i;
  int total = 0;

  for (i = 0; i < n; i++)
    total += i * i;

  return total;
}
```

--------------------------------

### Retrieve Source Location and Function Name

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Other-Builtins.html

Demonstrates using __builtin_FUNCTION, __builtin_FILE, and __builtin_LINE to capture context information.

```C
const char*
function (const char *func = __builtin_FUNCTION ())
{
  return func;
}

void foo (void)
{
  printf ("%s:%i: %s: message\n", file (), line (), function ());
}
```

--------------------------------

### __builtin_tbegin_nofloat

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/S_002f390-System-z-Built-in-Functions.html

Starts a non-constrained hardware transaction without FPR saves and restores.

```APIDOC
## int __builtin_tbegin_nofloat(void*)

### Description
Same as __builtin_tbegin but without FPR saves and restores. Using this variant in code making use of FPRs will leave the FPRs in undefined state when entering the transaction abort handler code.
```

--------------------------------

### __builtin_tbegin

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/S_002f390-System-z-Built-in-Functions.html

Generates the tbegin machine instruction to start a non-constrained hardware transaction.

```APIDOC
## int __builtin_tbegin(void*)

### Description
Generates the tbegin machine instruction starting a non-constrained hardware transaction. If the parameter is non-NULL, the memory area is used to store the transaction diagnostic buffer (TDB).

### Parameters
- **void*** (pointer) - Optional - Pointer to a transaction diagnostic buffer (TDB) or constant zero to prevent TDB writing.
```

--------------------------------

### Demonstrate Strub Mode Compatibility and Calls

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Common-Attributes.html

Shows how to assign functions with different strub modes to pointers and the resulting compatibility behavior.

```C
void __attribute__ ((strub))
bap (void)
{
  /* Assign a callable function to pointer-to-disabled.
     Flagged as not quite compatible with -Wpedantic.  */
  int __attribute__ ((strub ("disabled"))) (*d_p) (void) = bac;
  /* Not allowed: calls disabled type in a strub context.  */
  d_p ();

  /* Assign a disabled function to pointer-to-callable.
     Flagged as not quite compatible with -Wpedantic.  */
  int __attribute__ ((strub ("callable"))) (*c_p) (void) = bad;
  /* Ok, safe.  */
  c_p ();

  /* Assign an internal function to pointer-to-callable.
     Flagged as not quite compatible with -Wpedantic.  */
  c_p = bar;
  /* Ok, safe.  */
  c_p ();

  /* Assign an at-calls function to pointer-to-callable.
     Flaggged as incompatible.  */
  c_p = bal;
  /* The call through an interface-incompatible type will not use the
     modified interface expected by the at-calls function, so it is
     likely to misbehave at runtime.  */
  c_p ();
}
```

--------------------------------

### Preamble line format

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Invoking-Gcov.html

The format for preamble lines at the start of gcov output.

```text
-:0:tag:value
```

--------------------------------

### Perform Simple Arithmetic with Extended Asm

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Extended-Asm.html

An example for i386 demonstrating how to move a value between C variables and perform an addition using assembly.

```c
int src = 1;
int dst;   

asm ("mov %1, %0\n\t"
    "add $1, %0"
    : "=r" (dst) 
    : "r" (src));

printf("%d\n", dst);
```

--------------------------------

### Initialize v2sf values

Source: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/MIPS-Paired-Single-Support.html

Demonstrates initialization and assignment of v2sf vector types using aggregate syntax.

```c
v2sf a = {1.5, 9.1};
v2sf b;
float e, f;
b = (v2sf) {e, f};
```
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