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Hey everybody, I am struggling to get rid of a problem which seems to be related to a multi-return value optimization: I generate bitcode for a c++-function with llvm-g++ which is then linked, transformed and optimized at runtime using LLVM. The function has quite a few parameters, including structs and struct-pointers with 3 float fields. The problem is, that I require the function to preserve

Uh, sorry, did not pay attention where I was replying ;) Hey Duncan, I do not understand why this behaviour is required. What is the problem in having a function receive a single struct-parameter with three floats compared to two scalar parameters? source-code (C++): struct Test3Float { float a, b, c; }; void test(Test3Float param, Test3Float* result) { ... } bitcode: %"struct.Test3Float" = type { float, float, float } define void @_Z4test10Test3FloatPS_(double %param.0, float %param.1, %"struct.Test3Float"* %result) { ... } Best, Ralf Duncan Sands wrot...

Hi Ralf, > I do not understand why this behaviour is required. What is the problem > in having a function receive a single struct-parameter with three floats > compared to two scalar parameters? > > source-code (C++): > struct Test3Float { float a, b, c; }; > void test(Test3Float param, Test3Float* result) { ... } if you compile this with GCC, you will see that it too passes the first two floats in one double register, and the remaining float in a different register. The GCC people didn't make this behaviour up, they are fo...