Make the ptrtoint comparison simplification work if one side is a global.

llvm-svn: 91624

llvm/lib/Transforms/Scalar/InstructionCombining.cpp

@@ -6452,7 +6452,7 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
     //   if (X) ...
     // For generality, we handle any zero-extension of any operand comparison
     // with a constant or another cast from the same type.
-    if (isa<ConstantInt>(Op1) || isa<CastInst>(Op1))
+    if (isa<Constant>(Op1) || isa<CastInst>(Op1))
       if (Instruction *R = visitICmpInstWithCastAndCast(I))
         return R;
   }

llvm/test/Transforms/InstCombine/cast_ptr.ll

@@ -27,3 +27,12 @@ define i1 @test2(i8* %a, i8* %b) {
         ret i1 %r
 }
 
+; These casts should also be folded away.
+; CHECK: @test3
+; CHECK: icmp eq i8* %a, @global
+@global = global i8 0
+define i1 @test3(i8* %a) {
+        %tmpa = ptrtoint i8* %a to i32
+        %r = icmp eq i32 %tmpa, ptrtoint (i8* @global to i32)
+        ret i1 %r
+}