Intel i960 - Superblock Formation

Optimization
11-21
11
function is called from multiple sites, it is better to inline the function at
frequently executed call sites. The inlining decisions are made by the
gcdm960 program during the profiling decision-making step. After the
decisions have been made, the compiler performs the inlining during
profile-driven recompilation.
Superblock Formation
A superblock is a group of basic blocks that tend to execute in sequence (a
path) and can be entered only from their initial block. A superblock loop
is a superblock whose first block is the header of a loop, and for which
execution flow out of the last block usually goes to the first block. In
other words, a superblock loop is a heavily iterated loop where a single
path through the loop is taken quite frequently.
These concepts are illustrated in the following figure:
Figure 11-1 Superblock Formation Process
A
B
C
D
B
C
D D'
A
B
C
D D'
A
H
1
100
104
100
1
5
5
Trace ABD Superblock Loop ABD
Superblock ABD
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