[PATCH] D20627: Do not rename registers that do not start an independent live range

Krzysztof Parzyszek via llvm-commits llvm-commits at lists.llvm.org
Wed May 25 10:08:42 PDT 2016

kparzysz added inline comments.

Comment at: lib/CodeGen/AggressiveAntiDepBreaker.cpp:918
@@ +917,3 @@
+            if (R == AntiDepReg || TRI->isSubRegister(AntiDepReg, R))
+              continue;
+            AntiDepReg = 0;
kparzysz wrote:
> An output dependency could still defeat this test (i.e. we'd need to make sure that the later def in the output dependency starts a new live range), but I'll wait for more comments before making this change.
On the second thought, if the only aliased dependency was an output dependency on a register covered by the anti-dep register, renaming should be fine...



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