[PATCH] D17533: CXX_FAST_TLS calling convention: performance improvement for PPC64

[Kit Barton via llvm-commits]

kbarton added inline comments.

================
Comment at: lib/Target/PowerPC/PPCISelLowering.cpp:5821
@@ +5820,3 @@
+  if (I) {
+    for (; *I; ++I) {
+
----------------
Is this guaranteed to be a null-terminated list?
I looked quickly but could not find the answer.

================
Comment at: lib/Target/PowerPC/PPCISelLowering.h:446
@@ +445,3 @@
+    bool supportSplitCSR(MachineFunction *MF) const override {
+            return
+              MF->getFunction()->getCallingConv() == CallingConv::CXX_FAST_TLS &&
----------------
It could be my browser, but the indentation of the return looks way off.

================
Comment at: lib/Target/PowerPC/PPCRegisterInfo.cpp:145
@@ +144,3 @@
+    bool SaveR2 = !getReservedRegs(*MF).test(PPC::X2);
+    return TM.isPPC64()
+      ? (Subtarget.hasAltivec()
----------------
I thought this was disabled for 32-bit on line 11613 of PPCISelLowering.cpp.
Can you combine the check for 32-bit with the check for DarwinABI on line 138? That should simplify this logic a bit. 

================
Comment at: lib/Target/PowerPC/PPCRegisterInfo.cpp:153
@@ +152,3 @@
+            : CSR_SVR464_ViaCopy_SaveList))
+      : nullptr;
+  }
----------------
I find this nesting of conditional operators very difficult to read.


http://reviews.llvm.org/D17533