[llvm-dev] Replicate Individual O3 optimizations

[hameeza ahmed via llvm-dev]

Hello,
I want to study the individual O3 optimizations. For this I am using
following commands, but unable to replicate O3 behavior.

1. Documents/clang+llvm-9.0.0-x86_64-linux-gnu-ubuntu-18.04/bin/clang -O1
-Xclang -disable-llvm-passes -emit-llvm -S vecsum.c -o vecsum-noopt.ll

2. Documents/clang+llvm-9.0.0-x86_64-linux-gnu-ubuntu-18.04/bin/clang -O3
-mllvm -debug-pass=Arguments -emit-llvm -S vecsum.c

3. Documents/clang+llvm-9.0.0-x86_64-linux-gnu-ubuntu-18.04/bin/opt
<optimization sequence obtained in step 2> -S vecsum-noopt.ll -S -o
o3-chk.ll

Why the IR obtained by above step i.e individual O3 sequences, is not same
when O3 is passed?

Where I am doing mistake?

Please help.

Thank You
Regards
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