FCC

• FCC
  • Try it out on your machine
  • Implemented Optimization Passes
  • Currently Lowered C Features
    • Functions
    • Variables
    • Expressions
      • Assignment Operators
      • Binary arithmetic
      • Comparison operators
      • Unary operators
      • Logical operators
    • Control Flow
  • References

FCC is a optimizing compiler for a (growing) C99 subset.

Try it out on your machine

Build:

./bd

Run tests:

python tests.py

Use:

./build/fcc test.c

Requirements:

• CMake
• clang (22.1.8)
• clang development libraries
• graphviz (15.1.0)
• mold (optional)
• python

Implemented Optimization Passes

• Constant Folding
• Dead Branch Elimination
• Dead Block Elimination
• Constant Hoisting
• Dead Definition Elimination
• Block Merge

Currently Lowered C Features

Functions

• Function declarations and definitions
• Function calls

Variables

• Variable declarations
• Variable assignment
• SSA variable reads / writes with phi insertion

Expressions

Assignment Operators

• +=
• -=
• *=
• /=
• %=

Binary arithmetic

• Addition (+)
• Subtraction (-)
• Multiplication (*)
• Division (/)
• Modulus / Remainder (%)

Comparison operators

• Less than (<)
• Less than or equal (<=)
• Greater than (>)
• Greater than or equal (>=)
• Equal (==)
• Not equal (!=)

Unary operators

• Unary plus (+x)
• Unary minus (-x)
• Logical NOT (!x)
• Increment (pre & post)
• Decrement (pre & post)

Logical operators

• Logical AND (&&)
• Logical OR (||)

Control Flow

• if
• if-else
• while
• for
• break
• continue

References

• libclang: C Interface to Clang
• Simple and Efficient Construction of Static Single Assignment Form by Braun et al.