Register allocation

Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation
Control Flow Graph
CFG models flow of control in the program (procedure)
G = (N, E) as a directed graph
Node n ? N: basic blocks
• A basic block is a maximal sequence of stmts with a single entry point, single exit point, and no internal from branches
• For simplicity, we assume a unique entry node n0 and a unique exit node nf in later discussions
Edge e=(ni, nj) ? E: possible transfer of control block ni to block nj






Basic Blocks
A basic block is a maximal sequence of consecutive statements with a single entry point, a single exit point, and no internal
branches
• Basic unit in control flow analysis
• Local level of code optimizations
1. Redundancy elimination
2. Register-allocation