Refer to the given 3-address code sequence. This code sequence is split into basic blocks. The number of basic blocks is ________. (Answer in integer)1001: i = 1 1002: j = 1 1003: t1 = 10*i 1004: t2 = t1+j 1005: t3 = 8*t2 1006: t4 = t3-88 1007: a[t4] = 0.0 1008: j = j+1 1009: if j <= 10 goto 1003 1010: i = i+1 1011: if i <= 10 goto 1002 1012: i = 1 1013: t5 = i-1 1014: t6 = 88*t5 1015: a[t6] = 1.0 1016: i = i+1 1017: if i <= 10 goto 1013

To determine the number of basic blocks, we identify the leaders using the standard rules:

1. Rule 1 (First instruction): The first three-address instruction is a leader.

   • 1001

2. Rule 2 (Target of a jump): Any instruction that is the target of a conditional or unconditional jump is a leader.

   • Instruction 1009 jumps to 1003.

   • Instruction 1011 jumps to 1002.

   • Instruction 1017 jumps to 1013.

3. Rule 3 (Follows a jump): Any instruction that immediately follows a conditional or unconditional jump is a leader.

   • Instruction immediately following 1009 is 1010.

   • Instruction immediately following 1011 is 1012.

Thus, the set of leader instructions is:

Each leader begins a new basic block extending up to (but not including) the next leader or the end of the code:

• Block 1 ($B_1$):1001

• Block 2 ($B_2$):1002

• Block 3 ($B_3$):1003 to 1009

• Block 4 ($B_4$):1010 to 1011

• Block 5 ($B_5$):1012

• Block 6 ($B_6$):1013 to 1017

Therefore, the total number of basic blocks is 6.