[PATCH] D17633: [X86] Reuse EFLAGS and form LOCKed ops when only user is SETCC.

[JF Bastien via llvm-commits]

jfb added inline comments.

================
Comment at: lib/Target/X86/X86ISelLowering.cpp:25538
@@ +25537,3 @@
+  if (Cmp.getOpcode() != X86ISD::CMP &&
+      (Cmp.getOpcode() != X86ISD::SUB || Cmp.getNode()->hasAnyUseOfValue(0)))
+    return SDValue();
----------------
I find the inverted condition hard to read: IIUC you're trying to continue if the opcode is CMP, or if the opcode is SUB and its result is unused? I know checkBoolTestSetCCCombine does the same, and it's equally confusing IMO :)

================
Comment at: lib/Target/X86/X86ISelLowering.cpp:25571
@@ +25570,3 @@
+
+  SDValue LockOp = lowerAtomicArithWithLOCK(LHS, DAG);
+  DAG.ReplaceAllUsesOfValueWith(LHS.getValue(0),
----------------
Implementation for `lowerAtomicArithWithLOCK`?


http://reviews.llvm.org/D17633