[PATCH] D10826: Fix AArch64 prologue for empty frame with dynamic allocas

[Kristof Beyls]

kristof.beyls added inline comments.

================
Comment at: lib/Target/AArch64/AArch64FrameLowering.cpp:361-362
@@ -357,4 +360,4 @@
+    assert(MF.getRegInfo().isPhysRegUsed(scratchSPReg) &&
            "No scratch register to align SP!");
-    scratchSPReg = AArch64::X9;
   }
 
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t.p.northover wrote:
> eugenis wrote:
> > t.p.northover wrote:
> > > But X9 isn't callee-saved (AAPCS says it's temporary), so I don't think we need to worry about stack layouts: it's basically dead at this point.
> > > 
> > > Unless there's some assertion that *everything* is fixed by now?
> > Well, all tests pass.
> > Would you like me to switch to your variant?
> It seems like the simplest variant so far. I'd say so, unless Kristof objects.
I can't think of a reason not to do the simpler variant (always using X9 as the scratch register) - so no objections from my side.


http://reviews.llvm.org/D10826