Merging r168186: into the 3.2 release branch.

InstructionSimplify should be able to simplify A+B==B+A to 'true'
but wasn't due to the same logic bug that caused PR14361.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_32@168593 91177308-0d34-0410-b5e6-96231b3b80d8

Author: 32bitmicro

lib/Analysis/InstructionSimplify.cpp

@@ -2065,8 +2065,20 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
     if (A && C && (A == C || A == D || B == C || B == D) &&
         NoLHSWrapProblem && NoRHSWrapProblem) {
       // Determine Y and Z in the form icmp (X+Y), (X+Z).
-      Value *Y = (A == C || A == D) ? B : A;
-      Value *Z = (C == A || C == B) ? D : C;
+      Value *Y, *Z;
+      if (A == C) {
+        Y = B;
+        Z = D;
+      } else if (A == D) {
+        Y = B;
+        Z = C;
+      } else if (B == C) {
+        Y = A;
+        Z = D;
+      } else if (B == D) {
+        Y = A;
+        Z = C;
+      }
       if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse-1))
         return V;
     }

test/Transforms/InstSimplify/compare.ll

@@ -266,6 +266,15 @@ define i1 @add5(i32 %x, i32 %y) {
 ; CHECK: ret i1 true
 }
 
+define i1 @add6(i64 %A, i64 %B) {
+; CHECK: @add6
+  %s1 = add i64 %A, %B
+  %s2 = add i64 %B, %A
+  %cmp = icmp eq i64 %s1, %s2
+  ret i1 %cmp
+; CHECK: ret i1 true
+}
+
 define i1 @addpowtwo(i32 %x, i32 %y) {
 ; CHECK: @addpowtwo
   %l = lshr i32 %x, 1