[LLVMdev] Patch - big stackframes on SPU

[Kalle.Raiskila at nokia.com]

Hello all,

currently the SPU backend does not handle big stack frames (>16*511
bytes) nicely. llc asserts on malformed machine instructions.
(Assertion `MI->getOperand(OpNo).isImm() && "printDFormAddr first
operand is not immediate")

E.g. the function:
define i32 @foo() nounwind {
entry:
    %retval = alloca i32
    %big_data = alloca [1000 x i32]
    store i32 3840, i32* %retval, align 4
    br label %return

return:
    %retval2 = load i32* %retval
    ret i32 %retval2
}
demonstrates this issue.


Attached is a patch to fix this. It
-fixes a few small errors in function prologue and epilogue insertion
-enables register scavenging for frame index elimination
and
- implements the frame index elimination for big stacks.

Patch is made against latest svn head.


best regards,
Kalle Raiskila
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