How is GCC IR different from LLVM IR?
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I'm a complete newbie to compilers, and wasn't able to find anything relevant even after many hours of searching for an answer. Any insights would be helpful.
The most important fact is that LLVM IR and GCC IR (called GIMPLE) are not that different in their core - both are standard control-flow graphs of basic blocks, each block being a linear sequence of 2 inputs, 1 output instructions (so called "three-address code") which have been converted to SSA form. Most production compilers have been using this design since 1990-s. In pre-Clang times LLVM IR was even generated directly from GIMPLE via a GCC plugin.
Main advantages of LLVM IR are that it's less tightly bound to compiler implementation, more formally defined and has nicer C++ API. This allows for easier processing, transformation and analysis, which makes it IR of choice these days, both for compiler and for other related tools.
