[FIX] Handle pointer-pointer comparisons

  This should fix a problem introduced by r225464.

llvm-svn: 227404

polly/lib/CodeGen/IslExprBuilder.cpp

@@ -175,9 +175,33 @@ Value *IslExprBuilder::createOpBin(__isl_take isl_ast_expr *Expr) {
 
   LHS = create(isl_ast_expr_get_op_arg(Expr, 0));
   RHS = create(isl_ast_expr_get_op_arg(Expr, 1));
+  Type *LHSType = LHS->getType();
+  Type *RHSType = RHS->getType();
 
-  MaxType = LHS->getType();
-  MaxType = getWidestType(MaxType, RHS->getType());
+  // Handle <pointer> +/- <integer> and <integer> +/- <pointer>
+  if (LHSType->isPointerTy() || RHSType->isPointerTy()) {
+    isl_ast_expr_free(Expr);
+
+    assert((LHSType->isIntegerTy() || RHSType->isIntegerTy()) &&
+           "Arithmetic operations might only performed on one but not two "
+           "pointer types.");
+
+    if (LHSType->isIntegerTy())
+      std::swap(LHS, RHS);
+
+    switch (OpType) {
+    default:
+      llvm_unreachable(
+          "Only additive binary operations are allowed on pointer types.");
+    case isl_ast_op_sub:
+      RHS = Builder.CreateNeg(RHS);
+    // Fall through
+    case isl_ast_op_add:
+      return Builder.CreateGEP(LHS, RHS);
+    }
+  }
+
+  MaxType = getWidestType(LHSType, RHSType);
 
   // Take the result into account when calculating the widest type.
   //

polly/test/Isl/CodeGen/pointer-type-pointer-type-comparison.ll

@@ -0,0 +1,47 @@
+; RUN: opt %loadPolly -polly-ast -analyze < %s | FileCheck %s
+; RUN: opt %loadPolly -polly-codegen-isl -S < %s | FileCheck %s -check-prefix=CODEGEN
+;
+;    void f(int a[], int N, float *P, float *Q) {
+;      int i;
+;      for (i = 0; i < N; ++i)
+;        if ((P + 1) != Q)
+;          a[i] = i;
+;    }
+;
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+define void @f(i64* nocapture %a, i64 %N, float * %P, float * %Q) nounwind {
+entry:
+  br label %bb
+
+bb:
+  %i = phi i64 [ 0, %entry ], [ %i.inc, %bb.backedge ]
+  %brcond = icmp ne float* %P, %Q
+  br i1 %brcond, label %store, label %bb.backedge
+
+store:
+  %scevgep = getelementptr i64* %a, i64 %i
+  store i64 %i, i64* %scevgep
+  br label %bb.backedge
+
+bb.backedge:
+  %i.inc = add nsw i64 %i, 1
+  %exitcond = icmp eq i64 %i.inc, %N
+  br i1 %exitcond, label %return, label %bb
+
+return:
+  ret void
+}
+
+; CHECK: if (Q >= P + 1) {
+; CHECK:   for (int c0 = 0; c0 < N; c0 += 1)
+; CHECK:     Stmt_store(c0);
+; CHECK: } else if (P >= Q + 1)
+; CHECK:   for (int c0 = 0; c0 < N; c0 += 1)
+; CHECK:     Stmt_store(c0);
+; CHECK: }
+
+; CODEGEN:       %[[Pinc:[_a-zA-Z0-9]+]] = getelementptr float* %P, i64 1
+; CODEGEN-NEXT:                             icmp uge float* %Q, %[[Pinc]]
+; CODEGEN:       %[[Qinc:[_a-zA-Z0-9]+]] = getelementptr float* %Q, i64 1
+; CODEGEN-NEXT:                             icmp uge float* %P, %[[Qinc]]