[SCEV] Add tests with multiple NE guards and different orders.

Add additional test coverage for using NE guards added in 2d02726
(#160500)

Author: fhahn

llvm/test/Analysis/ScalarEvolution/ne-guard-multiple-trip-count.ll

@@ -0,0 +1,72 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -passes='print<scalar-evolution>' -disable-output %s 2>&1 | FileCheck %s
+
+declare void @foo()
+
+; Tests with multiple guards for the same value and different values.
+
+define void @test_guard_order_b_then_c_and_d(ptr %a, ptr %b, ptr %c, ptr %d) {
+; CHECK-LABEL: 'test_guard_order_b_then_c_and_d'
+; CHECK-NEXT:  Classifying expressions for: @test_guard_order_b_then_c_and_d
+; CHECK-NEXT:    %iv = phi ptr [ %a, %entry ], [ %iv.next, %loop ]
+; CHECK-NEXT:    --> {%a,+,1}<%loop> U: full-set S: full-set Exits: (-1 + (-1 * (ptrtoint ptr %a to i64)) + (ptrtoint ptr %b to i64) + %a) LoopDispositions: { %loop: Computable }
+; CHECK-NEXT:    %iv.next = getelementptr i8, ptr %iv, i64 1
+; CHECK-NEXT:    --> {(1 + %a),+,1}<%loop> U: full-set S: full-set Exits: ((-1 * (ptrtoint ptr %a to i64)) + (ptrtoint ptr %b to i64) + %a) LoopDispositions: { %loop: Computable }
+; CHECK-NEXT:  Determining loop execution counts for: @test_guard_order_b_then_c_and_d
+; CHECK-NEXT:  Loop %loop: backedge-taken count is (-1 + (-1 * (ptrtoint ptr %a to i64)) + (ptrtoint ptr %b to i64))
+; CHECK-NEXT:  Loop %loop: constant max backedge-taken count is i64 -2
+; CHECK-NEXT:  Loop %loop: symbolic max backedge-taken count is (-1 + (-1 * (ptrtoint ptr %a to i64)) + (ptrtoint ptr %b to i64))
+; CHECK-NEXT:  Loop %loop: Trip multiple is 1
+;
+entry:
+  %cmp.eq.b = icmp ne ptr %a, %b
+  %cmp.eq.c = icmp ne ptr %a, %c
+  %cmp.eq.d = icmp ne ptr %b, %d
+  call void @llvm.assume(i1 %cmp.eq.b)
+  call void @llvm.assume(i1 %cmp.eq.c)
+  call void @llvm.assume(i1 %cmp.eq.d)
+  br label %loop
+
+loop:
+  %iv = phi ptr [ %a, %entry ], [ %iv.next, %loop ]
+  %iv.next = getelementptr i8, ptr %iv, i64 1
+  call void @foo()
+  %ec = icmp eq ptr %iv.next, %b
+  br i1 %ec, label %exit, label %loop
+
+exit:
+  ret void
+}
+
+define void @test_guard_order_d_then_c_and_b(ptr %a, ptr %b, ptr %c, ptr %d) {
+; CHECK-LABEL: 'test_guard_order_d_then_c_and_b'
+; CHECK-NEXT:  Classifying expressions for: @test_guard_order_d_then_c_and_b
+; CHECK-NEXT:    %iv = phi ptr [ %a, %entry ], [ %iv.next, %loop ]
+; CHECK-NEXT:    --> {%a,+,1}<%loop> U: full-set S: full-set Exits: (-1 + (-1 * (ptrtoint ptr %a to i64)) + (ptrtoint ptr %b to i64) + %a) LoopDispositions: { %loop: Computable }
+; CHECK-NEXT:    %iv.next = getelementptr i8, ptr %iv, i64 1
+; CHECK-NEXT:    --> {(1 + %a),+,1}<%loop> U: full-set S: full-set Exits: ((-1 * (ptrtoint ptr %a to i64)) + (ptrtoint ptr %b to i64) + %a) LoopDispositions: { %loop: Computable }
+; CHECK-NEXT:  Determining loop execution counts for: @test_guard_order_d_then_c_and_b
+; CHECK-NEXT:  Loop %loop: backedge-taken count is (-1 + (-1 * (ptrtoint ptr %a to i64)) + (ptrtoint ptr %b to i64))
+; CHECK-NEXT:  Loop %loop: constant max backedge-taken count is i64 -2
+; CHECK-NEXT:  Loop %loop: symbolic max backedge-taken count is (-1 + (-1 * (ptrtoint ptr %a to i64)) + (ptrtoint ptr %b to i64))
+; CHECK-NEXT:  Loop %loop: Trip multiple is 1
+;
+entry:
+  %cmp.eq.b = icmp ne ptr %a, %b
+  %cmp.eq.c = icmp ne ptr %a, %c
+  %cmp.eq.d = icmp ne ptr %b, %d
+  call void @llvm.assume(i1 %cmp.eq.d)
+  call void @llvm.assume(i1 %cmp.eq.c)
+  call void @llvm.assume(i1 %cmp.eq.b)
+  br label %loop
+
+loop:
+  %iv = phi ptr [ %a, %entry ], [ %iv.next, %loop ]
+  %iv.next = getelementptr i8, ptr %iv, i64 1
+  call void @foo()
+  %ec = icmp eq ptr %iv.next, %b
+  br i1 %ec, label %exit, label %loop
+
+exit:
+  ret void
+}