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Re: [PATCH, powerpc], Fix PR48857, pass/return V2DI as other vector types
On Tue, May 03, 2011 at 10:51:51PM -0400, David Edelsohn wrote:
> What does this do to the ABI? Haven't we now broken the ABI and
> broken backwards compatibility?
In this case, GCC wasn't following the ABI. My patch will have GCC follow the
ABI. The XL compiler also follows the ABI. So we have to decide whether to
keep the current calling sequence which violates the ABI, or change the
compiler to follow the ABI, and break backwards compatiblity.
Given the machine doesn't have native VD2Imode operations, except for
conversion to/from floating point, and the bitwise operations, I suspect not to
many people use the data type. Note, V2DImode was added in GCC 4.5 when the
VSX support was added. It was not in the earlier Altivec support.
The MODES_TIEABLE_P part of the patch will need to go in to fix PR 48495 (it
was in looking at the bug we discovered that the compiler was not following the
ABI).
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Michael Meissner, IBM
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