[IndVars,LV] Add tests with pointer-based loop guards.

Add tests with pointer-based loop guards.

Author: fhahn

llvm/test/Transforms/IndVarSimplify/pointer-loop-guards.ll

@@ -0,0 +1,50 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
+; RUN: opt -p indvars -S %s | FileCheck %s
+
+declare i1 @cond()
+
+define i64 @test_ptr_compare_guard(ptr %start, ptr %end) {
+; CHECK-LABEL: define i64 @test_ptr_compare_guard(
+; CHECK-SAME: ptr [[START:%.*]], ptr [[END:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*]]:
+; CHECK-NEXT:    [[C_0:%.*]] = icmp eq ptr [[START]], [[END]]
+; CHECK-NEXT:    br i1 [[C_0]], label %[[EXIT:.*]], label %[[LOOP_HEADER_PREHEADER:.*]]
+; CHECK:       [[LOOP_HEADER_PREHEADER]]:
+; CHECK-NEXT:    br label %[[LOOP_HEADER:.*]]
+; CHECK:       [[LOOP_HEADER]]:
+; CHECK-NEXT:    [[PTR_IV:%.*]] = phi ptr [ [[PTR_IV_NEXT:%.*]], %[[LOOP_LATCH:.*]] ], [ [[START]], %[[LOOP_HEADER_PREHEADER]] ]
+; CHECK-NEXT:    [[I64_IV:%.*]] = phi i64 [ [[I64_IV_NEXT:%.*]], %[[LOOP_LATCH]] ], [ 0, %[[LOOP_HEADER_PREHEADER]] ]
+; CHECK-NEXT:    [[C_1:%.*]] = call i1 @cond()
+; CHECK-NEXT:    br i1 [[C_1]], label %[[LOOP_LATCH]], label %[[EXIT_LOOPEXIT:.*]]
+; CHECK:       [[LOOP_LATCH]]:
+; CHECK-NEXT:    [[PTR_IV_NEXT]] = getelementptr i8, ptr [[PTR_IV]], i64 1
+; CHECK-NEXT:    [[I64_IV_NEXT]] = add i64 [[I64_IV]], 1
+; CHECK-NEXT:    [[C_2:%.*]] = icmp eq ptr [[PTR_IV_NEXT]], [[END]]
+; CHECK-NEXT:    br i1 [[C_2]], label %[[EXIT_LOOPEXIT]], label %[[LOOP_HEADER]]
+; CHECK:       [[EXIT_LOOPEXIT]]:
+; CHECK-NEXT:    [[RES_PH:%.*]] = phi i64 [ 0, %[[LOOP_HEADER]] ], [ [[I64_IV]], %[[LOOP_LATCH]] ]
+; CHECK-NEXT:    br label %[[EXIT]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    [[RES:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[RES_PH]], %[[EXIT_LOOPEXIT]] ]
+; CHECK-NEXT:    ret i64 [[RES]]
+;
+entry:
+  %c.0 = icmp eq ptr %start, %end
+  br i1 %c.0, label %exit, label %loop.header
+
+loop.header:
+  %ptr.iv = phi ptr [ %start, %entry ], [ %ptr.iv.next, %loop.latch ]
+  %i64.iv = phi i64 [ 0, %entry ], [ %i64.iv.next, %loop.latch ]
+  %c.1 = call i1 @cond()
+  br i1 %c.1, label %loop.latch, label %exit
+
+loop.latch:
+  %ptr.iv.next = getelementptr i8, ptr %ptr.iv, i64 1
+  %i64.iv.next = add i64 %i64.iv, 1
+  %c.2 = icmp eq ptr %ptr.iv.next, %end
+  br i1 %c.2, label %exit, label %loop.header
+
+exit:
+  %res = phi i64 [ 0, %entry ], [ %i64.iv, %loop.latch ], [ 0, %loop.header ]
+  ret i64 %res
+}