[LLVMdev] subtle issue with soft-float and new attribute scheme (possibly an issue with other attributes)
rkotler at mips.com
Fri May 17 03:04:20 PDT 2013
I can't say this is a bug it is changed behavior from before the new
This issue may appear with other attributes. (there are other attributes
that clang will now place
on each function)
If you run clang as a single pass to create a .ll and don't say
-msoft-float, it puts the attribute use-soft-float=false on every
function. (It used to be that in that case -msoft-float had no effect
attributes where not preserved in the IL. )
Then if you run llc and say -soft-float, what happens is that the code
generator will compile everything as soft-float, but the value of the
following will be false in XXXISelLowering
When the constructor for XXXISelLowering is called,
TM.Options.UseSoftFloat will be true.
What is interesting is that code for "make check" won't have any of the
new attributes there so
it will work as before.
I was seeing this behavior and could not figure out how my tests could
possibly pass if getTargetMachine().Options.UseSoftFloat was returning
the wrong result.
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