[PATCH] [MIPS] fix extension of integer types (function calls)

[Daniel Sanders]

This seems to be a backend bug rather than a frontend bug. The backend should be able to handle functions like `declare void @foo(i32 signext, i128 signext)` correctly but it currently doesn't. The backend has everything it needs (including the alignment) to handle it correctly though. The alignment can be found in ArgFlags.getOrigAlign() and can be checked with CCIfAlign.

It should be possible to fix this in a frontend-independent way by adding something like 'CCIfType<[i64], CCIfAlign<"8", CCAssignToRegWithShadow<[A0_64, A2_64, ...], [D12_64, D14_64, ...]>>>' but it also needs something to mark the skipped registers as being allocated so that subsequent arguments don't try to fill in the gaps this leaves behind.
Another possibility is adding a new action to tablegen (CCRegAlign?) which walks through the unallocated argument registers and marks them allocated until it finds a register with a suitable alignment.

Would you be willing to look into a backend fix for this?


http://reviews.llvm.org/D9198

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