Steve, Thanks for raising my attention, I've got a proposal below.
> The MIPS32 architecture supports madd, msub, nmadd, and nmsub instructions > as well as rsqrt and recip instructions even when it doesn't have a 64 bit > floating point unit. This was not clear in the original MIPS32 architecture > document (MD00086) but was clarified in 2011 (version 3.0.2, March 21, 2011). > This patch updates the ISA_HAS_FP4 and ISA_HAS_NMADD4_NMSUB4 macros and the > recip_condition mode attribute to allow the use of these instructions for all > MIPS32 architectures (with or without FLOAT64). > > Testing showed one new test failure (gcc.target/mips/rsqrt-4.c) which I > updated to reflect that we can now generate and use a rsqrt.d instruction. > > I put Chao-ying and Maciej's names on the patch since they did the > original changes in GCC but those changes were never checked in upstream. I've got the changes scheduled for upstream submission, but testing against upstream GCC used to be problematic for various reasons and then disappeared from the radar owing to other stuff; in any case apologies for the delay incurred. However I believe I have a more complete version of the change, including in particular a number of code simplifications as well as a documentation update, although no update for the reciprocals (that I think should be handled separately; I reckon there was some peculiarity there). Given that, how about we coordinate these submissions -- I'll dig out the most recent version of the madd change and push it through testing before I post it and you do the reciprocals? Maciej
