================
Comment at: lib/CodeGen/TargetInfo.cpp:3481
@@ -3457,1 +3480,3 @@
+    // the stack.
+    AllocatedVFP = 17;
     return;
----------------
Renato Golin wrote:
> Oliver Stannard wrote:
> > Renato Golin wrote:
> > > Why are you saturating? Is there any place that especially check against 
> > > 17? Or are all of them like this, >=16?
> > On line 3336, we check whether AllocatedVFP > 16, as we need to know 
> > whether some CPRCs have been allocated on the stack.
> Shouldn't we just change that check, then? I think it makes more sense.
This can't be done just by changing the check.

Without the line "AllocatedVFP = 17;", AllocatedVFPs will be set to 16 for the 
following two cases:
 * 8 doubles - exactly fills the VFP registers
 * 9 doubles - fills the VFP registers with no gaps, plus one double on the 
stack

However, we need to differentiate between the two cases, as in the first we can 
split a struct between the GPRs and stack, but in the second case we cannot. 
(AAPCS rule C.5)

Because of this, I am using (AllocatedVFPs > NumVFPs) to signify that at least 
one CPRC has been allocated to the stack, and the same with AllocatedGPRs. Once 
AllocatedVFPs > NumVFPs, we don't actually need to track the exact number of 
bytes used on the stack, only that this is non-zero.


http://llvm-reviews.chandlerc.com/D2726
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