Improve bool folding

src/IceTargetLoweringX86Base.h

Index: src/IceTargetLoweringX86Base.h
diff --git a/src/IceTargetLoweringX86Base.h b/src/IceTargetLoweringX86Base.h
index bd09b5d2eb01b5f47dce3e052eda616daa342d31..ff054b2b347c8112da0d600676dea196cc5f3c5a 100644
--- a/src/IceTargetLoweringX86Base.h
+++ b/src/IceTargetLoweringX86Base.h
@@ -722,6 +722,10 @@ private:
 
   /// Emit the code for a combined compare and branch, or sets the destination

[Jim Stichnoth, 2015/11/11 14:05:20]

Nit 1: "set" instead of "sets".
Nit 2: "if Br == nullptr" (for accuracy, and agreement with setccOrBr).
Nit 3: Document both methods with the same comment.

Suggestion:

  /// Emit the code for a combined icmp/branch or fcmp/branch, or set the
  /// destination variable of the compare if Br == nullptr.
  void lowerIcmpAndBr(const InstIcmp *Icmp, const InstBr *Br);
  void lowerFcmpAndBr(const InstIcmp *Icmp, const InstBr *Br);

Even better if you know how to make this combined comment doxygen-friendly.

[sehr, 2015/11/13 06:00:52]

Doxygen is over my head :-).  Done otherwise.

   /// variable of the compare if branch is nullptr.
+  void lowerFcmpAndBr(const InstFcmp *Fcmp, const InstBr *Br);
+
+  /// Emit the code for a combined compare and branch, or sets the destination
+  /// variable of the compare if branch is nullptr.
   void lowerIcmpAndBr(const InstIcmp *Icmp, const InstBr *Br);
 
   /// Emit a setcc instruction if Br == nullptr; otherwise emit a branch.
@@ -731,6 +735,9 @@ private:
   /// Emit a mov [1|0] instruction if Br == nullptr; otherwise emit a branch.
   void movOrBr(bool IcmpResult, Variable *Dest, const InstBr *Br);
 
+  /// Emit the code for a combined arithmetic instruction and branch.
+  void lowerArithAndBr(const InstArithmetic *Arith, const InstBr *Br);
+
   /// Complains loudly if invoked because the cpu can handle 64-bit types
   /// natively.
   template <typename T = Traits>