[LLVMbugs] [Bug 4059] New: ARM: double arguments may be split between registers and stack with AAPCS ABI

[bugzilla-daemon at cs.uiuc.edu]

http://llvm.org/bugs/show_bug.cgi?id=4059

           Summary: ARM: double arguments may be split between registers and
                    stack with AAPCS ABI
           Product: libraries
           Version: trunk
          Platform: Macintosh
        OS/Version: MacOS X
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Backend: ARM
        AssignedTo: unassignedbugs at nondot.org
        ReportedBy: bob.wilson at apple.com
                CC: llvmbugs at cs.uiuc.edu


Created an attachment (id=2871)
 --> (http://llvm.org/bugs/attachment.cgi?id=2871)
testcase

This is similar to pr4058, which involves ia64 arguments.  Double
floating-point arguments (f64) work correctly if the target architecture
includes the VFP floating-point registers.  Otherwise, f64 arguments get split
up into i32/i32 pairs and the tests for f64 in ARMCallingConv.td fail.  The
base AAPCS ABI requires f64 arguments to be passed in even/odd register pairs
or on the stack, and the ABI applies whether you have VFP support or not. 
(There is an optional hard-float variant of AAPCS but LLVM does not support
that yet.)  f64 arguments cannot be split between r3 and the stack when using
AAPCS.  The attached testcase demonstrates the problem.


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