diff --git a/llvm/test/Transforms/ConstraintElimination/monotonic-phis.ll b/llvm/test/Transforms/ConstraintElimination/monotonic-phis.ll
new file mode 100644
index 0000000000000..cc76bb9897fa4
--- /dev/null
+++ b/llvm/test/Transforms/ConstraintElimination/monotonic-phis.ll
@@ -0,0 +1,628 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -passes=constraint-elimination -S %s | FileCheck %s
+
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+
+
+declare void @use(ptr)
+declare void @llvm.assume(i1)
+
+define void @test_monotonic_ptr_iv_inc_1_eq_to_uge(ptr %start, i16 %len) {
+; CHECK-LABEL: @test_monotonic_ptr_iv_inc_1_eq_to_uge(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[UPPER:%.*]] = getelementptr inbounds i32, ptr [[START:%.*]], i16 [[LEN:%.*]]
+; CHECK-NEXT:    [[LEN_NEG:%.*]] = icmp slt i16 [[LEN]], 0
+; CHECK-NEXT:    br i1 [[LEN_NEG]], label [[EXIT:%.*]], label [[LOOP_PH:%.*]]
+; CHECK:       loop.ph:
+; CHECK-NEXT:    br label [[LOOP_HEADER:%.*]]
+; CHECK:       loop.header:
+; CHECK-NEXT:    [[PTR_IV:%.*]] = phi ptr [ [[START]], [[LOOP_PH]] ], [ [[PTR_IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
+; CHECK-NEXT:    [[C:%.*]] = icmp eq ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    br i1 [[C]], label [[EXIT]], label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[T_1:%.*]] = icmp uge ptr [[PTR_IV]], [[START]]
+; CHECK-NEXT:    [[T_2:%.*]] = icmp ult ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    [[AND:%.*]] = and i1 [[T_1]], [[T_2]]
+; CHECK-NEXT:    br i1 [[AND]], label [[LOOP_LATCH]], label [[EXIT]]
+; CHECK:       loop.latch:
+; CHECK-NEXT:    call void @use(ptr [[PTR_IV]])
+; CHECK-NEXT:    [[PTR_IV_NEXT]] = getelementptr inbounds i32, ptr [[PTR_IV]], i16 1
+; CHECK-NEXT:    br label [[LOOP_HEADER]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %upper = getelementptr inbounds i32, ptr %start, i16 %len
+  %len.neg = icmp slt i16 %len, 0
+  br i1 %len.neg, label %exit, label %loop.ph
+
+loop.ph:
+  br label %loop.header
+
+loop.header:
+  %ptr.iv = phi ptr [ %start, %loop.ph ], [ %ptr.iv.next, %loop.latch ]
+  %c = icmp eq ptr %ptr.iv, %upper
+  br i1 %c, label %exit, label %for.body
+
+for.body:
+  %t.1 = icmp uge ptr %ptr.iv, %start
+  %t.2 = icmp ult ptr %ptr.iv, %upper
+  %and = and i1 %t.1, %t.2
+  br i1 %and, label %loop.latch, label %exit
+
+loop.latch:
+  call void @use(ptr %ptr.iv)
+  %ptr.iv.next = getelementptr inbounds i32, ptr %ptr.iv, i16 1
+  br label %loop.header
+
+exit:
+  ret void
+}
+
+define void @test_monotonic_ptr_iv_inc_1_eq_to_uge_incoming_values_reordered(ptr %start, i16 %len) {
+; CHECK-LABEL: @test_monotonic_ptr_iv_inc_1_eq_to_uge_incoming_values_reordered(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[UPPER:%.*]] = getelementptr inbounds i32, ptr [[START:%.*]], i16 [[LEN:%.*]]
+; CHECK-NEXT:    [[LEN_NEG:%.*]] = icmp slt i16 [[LEN]], 0
+; CHECK-NEXT:    br i1 [[LEN_NEG]], label [[EXIT:%.*]], label [[LOOP_PH:%.*]]
+; CHECK:       loop.ph:
+; CHECK-NEXT:    br label [[LOOP_HEADER:%.*]]
+; CHECK:       loop.header:
+; CHECK-NEXT:    [[PTR_IV:%.*]] = phi ptr [ [[PTR_IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ], [ [[START]], [[LOOP_PH]] ]
+; CHECK-NEXT:    [[C:%.*]] = icmp eq ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    br i1 [[C]], label [[EXIT]], label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[T_1:%.*]] = icmp uge ptr [[PTR_IV]], [[START]]
+; CHECK-NEXT:    [[T_2:%.*]] = icmp ult ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    [[AND:%.*]] = and i1 [[T_1]], [[T_2]]
+; CHECK-NEXT:    br i1 [[AND]], label [[LOOP_LATCH]], label [[EXIT]]
+; CHECK:       loop.latch:
+; CHECK-NEXT:    call void @use(ptr [[PTR_IV]])
+; CHECK-NEXT:    [[PTR_IV_NEXT]] = getelementptr inbounds i32, ptr [[PTR_IV]], i16 1
+; CHECK-NEXT:    br label [[LOOP_HEADER]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %upper = getelementptr inbounds i32, ptr %start, i16 %len
+  %len.neg = icmp slt i16 %len, 0
+  br i1 %len.neg, label %exit, label %loop.ph
+
+loop.ph:
+  br label %loop.header
+
+loop.header:
+  %ptr.iv = phi ptr [ %ptr.iv.next, %loop.latch ], [ %start, %loop.ph ]
+  %c = icmp eq ptr %ptr.iv, %upper
+  br i1 %c, label %exit, label %for.body
+
+for.body:
+  %t.1 = icmp uge ptr %ptr.iv, %start
+  %t.2 = icmp ult ptr %ptr.iv, %upper
+  %and = and i1 %t.1, %t.2
+  br i1 %and, label %loop.latch, label %exit
+
+loop.latch:
+  call void @use(ptr %ptr.iv)
+  %ptr.iv.next = getelementptr inbounds i32, ptr %ptr.iv, i16 1
+  br label %loop.header
+
+exit:
+  ret void
+}
+
+define void @test_monotonic_ptr_iv_inc_1_eq_to_uge_no_preheader(ptr %start, i16 %len) {
+; CHECK-LABEL: @test_monotonic_ptr_iv_inc_1_eq_to_uge_no_preheader(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[UPPER:%.*]] = getelementptr inbounds i32, ptr [[START:%.*]], i16 [[LEN:%.*]]
+; CHECK-NEXT:    [[LEN_NEG:%.*]] = icmp slt i16 [[LEN]], 0
+; CHECK-NEXT:    br i1 [[LEN_NEG]], label [[EXIT:%.*]], label [[LOOP_HEADER:%.*]]
+; CHECK:       loop.header:
+; CHECK-NEXT:    [[PTR_IV:%.*]] = phi ptr [ [[START]], [[ENTRY:%.*]] ], [ [[PTR_IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
+; CHECK-NEXT:    [[C:%.*]] = icmp eq ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    br i1 [[C]], label [[EXIT]], label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[T_1:%.*]] = icmp uge ptr [[PTR_IV]], [[START]]
+; CHECK-NEXT:    [[T_2:%.*]] = icmp ult ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    [[AND:%.*]] = and i1 [[T_1]], [[T_2]]
+; CHECK-NEXT:    br i1 [[AND]], label [[LOOP_LATCH]], label [[EXIT]]
+; CHECK:       loop.latch:
+; CHECK-NEXT:    call void @use(ptr [[PTR_IV]])
+; CHECK-NEXT:    [[PTR_IV_NEXT]] = getelementptr inbounds i32, ptr [[PTR_IV]], i16 1
+; CHECK-NEXT:    br label [[LOOP_HEADER]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %upper = getelementptr inbounds i32, ptr %start, i16 %len
+  %len.neg = icmp slt i16 %len, 0
+  br i1 %len.neg, label %exit, label %loop.header
+
+loop.header:
+  %ptr.iv = phi ptr [ %start, %entry ], [ %ptr.iv.next, %loop.latch ]
+  %c = icmp eq ptr %ptr.iv, %upper
+  br i1 %c, label %exit, label %for.body
+
+for.body:
+  %t.1 = icmp uge ptr %ptr.iv, %start
+  %t.2 = icmp ult ptr %ptr.iv, %upper
+  %and = and i1 %t.1, %t.2
+  br i1 %and, label %loop.latch, label %exit
+
+loop.latch:
+  call void @use(ptr %ptr.iv)
+  %ptr.iv.next = getelementptr inbounds i32, ptr %ptr.iv, i16 1
+  br label %loop.header
+
+exit:
+  ret void
+}
+
+define void @test_ptr_iv_upper_may_be_less_than_start(ptr %start, i16 %len) {
+; CHECK-LABEL: @test_ptr_iv_upper_may_be_less_than_start(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[UPPER:%.*]] = getelementptr inbounds i32, ptr [[START:%.*]], i16 [[LEN:%.*]]
+; CHECK-NEXT:    br label [[LOOP_HEADER:%.*]]
+; CHECK:       loop.header:
+; CHECK-NEXT:    [[PTR_IV:%.*]] = phi ptr [ [[START]], [[ENTRY:%.*]] ], [ [[PTR_IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
+; CHECK-NEXT:    [[C:%.*]] = icmp eq ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    br i1 [[C]], label [[EXIT:%.*]], label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[T_1:%.*]] = icmp uge ptr [[PTR_IV]], [[START]]
+; CHECK-NEXT:    [[T_2:%.*]] = icmp ult ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    [[AND:%.*]] = and i1 [[T_1]], [[T_2]]
+; CHECK-NEXT:    br i1 [[AND]], label [[LOOP_LATCH]], label [[EXIT]]
+; CHECK:       loop.latch:
+; CHECK-NEXT:    call void @use(ptr [[PTR_IV]])
+; CHECK-NEXT:    [[PTR_IV_NEXT]] = getelementptr inbounds i32, ptr [[PTR_IV]], i16 1
+; CHECK-NEXT:    br label [[LOOP_HEADER]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %upper = getelementptr inbounds i32, ptr %start, i16 %len
+  br label %loop.header
+
+loop.header:
+  %ptr.iv = phi ptr [ %start, %entry ], [ %ptr.iv.next, %loop.latch ]
+  %c = icmp eq ptr %ptr.iv, %upper
+  br i1 %c, label %exit, label %for.body
+
+for.body:
+  %t.1 = icmp uge ptr %ptr.iv, %start
+  %t.2 = icmp ult ptr %ptr.iv, %upper
+  %and = and i1 %t.1, %t.2
+  br i1 %and, label %loop.latch, label %exit
+
+loop.latch:
+  call void @use(ptr %ptr.iv)
+  %ptr.iv.next = getelementptr inbounds i32, ptr %ptr.iv, i16 1
+  br label %loop.header
+
+exit:
+  ret void
+}
+
+define void @test_no_ptr_iv_step_inst_doesnt_use_phi(ptr %start, ptr %p, i16 %len) {
+; CHECK-LABEL: @test_no_ptr_iv_step_inst_doesnt_use_phi(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[UPPER:%.*]] = getelementptr inbounds i32, ptr [[START:%.*]], i16 [[LEN:%.*]]
+; CHECK-NEXT:    [[LEN_NEG:%.*]] = icmp slt i16 [[LEN]], 0
+; CHECK-NEXT:    br i1 [[LEN_NEG]], label [[EXIT:%.*]], label [[LOOP_PH:%.*]]
+; CHECK:       loop.ph:
+; CHECK-NEXT:    br label [[LOOP_HEADER:%.*]]
+; CHECK:       loop.header:
+; CHECK-NEXT:    [[PTR_IV:%.*]] = phi ptr [ [[START]], [[LOOP_PH]] ], [ [[PTR_IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
+; CHECK-NEXT:    [[C:%.*]] = icmp eq ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    br i1 [[C]], label [[EXIT]], label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[T_1:%.*]] = icmp uge ptr [[PTR_IV]], [[START]]
+; CHECK-NEXT:    [[T_2:%.*]] = icmp ult ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    [[AND:%.*]] = and i1 [[T_1]], [[T_2]]
+; CHECK-NEXT:    br i1 [[AND]], label [[LOOP_LATCH]], label [[EXIT]]
+; CHECK:       loop.latch:
+; CHECK-NEXT:    call void @use(ptr [[PTR_IV]])
+; CHECK-NEXT:    [[PTR_IV_NEXT]] = getelementptr inbounds i32, ptr [[P:%.*]], i16 1
+; CHECK-NEXT:    br label [[LOOP_HEADER]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %upper = getelementptr inbounds i32, ptr %start, i16 %len
+  %len.neg = icmp slt i16 %len, 0
+  br i1 %len.neg, label %exit, label %loop.ph
+
+loop.ph:
+  br label %loop.header
+
+loop.header:
+  %ptr.iv = phi ptr [ %start, %loop.ph ], [ %ptr.iv.next, %loop.latch ]
+  %c = icmp eq ptr %ptr.iv, %upper
+  br i1 %c, label %exit, label %for.body
+
+for.body:
+  %t.1 = icmp uge ptr %ptr.iv, %start
+  %t.2 = icmp ult ptr %ptr.iv, %upper
+  %and = and i1 %t.1, %t.2
+  br i1 %and, label %loop.latch, label %exit
+
+loop.latch:
+  call void @use(ptr %ptr.iv)
+  %ptr.iv.next = getelementptr inbounds i32, ptr %p, i16 1
+  br label %loop.header
+
+exit:
+  ret void
+}
+
+define void @test_no_ptr_iv_different_start(ptr %start, ptr %p, i16 %len) {
+; CHECK-LABEL: @test_no_ptr_iv_different_start(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[UPPER:%.*]] = getelementptr inbounds i32, ptr [[START:%.*]], i16 [[LEN:%.*]]
+; CHECK-NEXT:    [[LEN_NEG:%.*]] = icmp slt i16 [[LEN]], 0
+; CHECK-NEXT:    br i1 [[LEN_NEG]], label [[EXIT:%.*]], label [[LOOP_PH:%.*]]
+; CHECK:       loop.ph:
+; CHECK-NEXT:    br label [[LOOP_HEADER:%.*]]
+; CHECK:       loop.header:
+; CHECK-NEXT:    [[PTR_IV:%.*]] = phi ptr [ [[P:%.*]], [[LOOP_PH]] ], [ [[PTR_IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
+; CHECK-NEXT:    [[C:%.*]] = icmp eq ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    br i1 [[C]], label [[EXIT]], label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[T_1:%.*]] = icmp uge ptr [[PTR_IV]], [[START]]
+; CHECK-NEXT:    [[T_2:%.*]] = icmp ult ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    [[AND:%.*]] = and i1 [[T_1]], [[T_2]]
+; CHECK-NEXT:    br i1 [[AND]], label [[LOOP_LATCH]], label [[EXIT]]
+; CHECK:       loop.latch:
+; CHECK-NEXT:    call void @use(ptr [[PTR_IV]])
+; CHECK-NEXT:    [[PTR_IV_NEXT]] = getelementptr inbounds i32, ptr [[PTR_IV]], i16 1
+; CHECK-NEXT:    br label [[LOOP_HEADER]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %upper = getelementptr inbounds i32, ptr %start, i16 %len
+  %len.neg = icmp slt i16 %len, 0
+  br i1 %len.neg, label %exit, label %loop.ph
+
+loop.ph:
+  br label %loop.header
+
+loop.header:
+  %ptr.iv = phi ptr [ %p, %loop.ph ], [ %ptr.iv.next, %loop.latch ]
+  %c = icmp eq ptr %ptr.iv, %upper
+  br i1 %c, label %exit, label %for.body
+
+for.body:
+  %t.1 = icmp uge ptr %ptr.iv, %start
+  %t.2 = icmp ult ptr %ptr.iv, %upper
+  %and = and i1 %t.1, %t.2
+  br i1 %and, label %loop.latch, label %exit
+
+loop.latch:
+  call void @use(ptr %ptr.iv)
+  %ptr.iv.next = getelementptr inbounds i32, ptr %ptr.iv, i16 1
+  br label %loop.header
+
+exit:
+  ret void
+}
+
+define void @test_ptr_iv_not_inbounds(ptr %start, i16 %len) {
+; CHECK-LABEL: @test_ptr_iv_not_inbounds(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[UPPER:%.*]] = getelementptr inbounds i32, ptr [[START:%.*]], i16 [[LEN:%.*]]
+; CHECK-NEXT:    [[LEN_NEG:%.*]] = icmp slt i16 [[LEN]], 0
+; CHECK-NEXT:    br i1 [[LEN_NEG]], label [[EXIT:%.*]], label [[LOOP_PH:%.*]]
+; CHECK:       loop.ph:
+; CHECK-NEXT:    br label [[LOOP_HEADER:%.*]]
+; CHECK:       loop.header:
+; CHECK-NEXT:    [[PTR_IV:%.*]] = phi ptr [ [[START]], [[LOOP_PH]] ], [ [[PTR_IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
+; CHECK-NEXT:    [[C:%.*]] = icmp eq ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    br i1 [[C]], label [[EXIT]], label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[T_1:%.*]] = icmp uge ptr [[PTR_IV]], [[START]]
+; CHECK-NEXT:    [[T_2:%.*]] = icmp ult ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    [[AND:%.*]] = and i1 [[T_1]], [[T_2]]
+; CHECK-NEXT:    br i1 [[AND]], label [[LOOP_LATCH]], label [[EXIT]]
+; CHECK:       loop.latch:
+; CHECK-NEXT:    call void @use(ptr [[PTR_IV]])
+; CHECK-NEXT:    [[PTR_IV_NEXT]] = getelementptr i32, ptr [[PTR_IV]], i16 1
+; CHECK-NEXT:    br label [[LOOP_HEADER]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %upper = getelementptr inbounds i32, ptr %start, i16 %len
+  %len.neg = icmp slt i16 %len, 0
+  br i1 %len.neg, label %exit, label %loop.ph
+
+loop.ph:
+  br label %loop.header
+
+loop.header:
+  %ptr.iv = phi ptr [ %start, %loop.ph ], [ %ptr.iv.next, %loop.latch ]
+  %c = icmp eq ptr %ptr.iv, %upper
+  br i1 %c, label %exit, label %for.body
+
+for.body:
+  %t.1 = icmp uge ptr %ptr.iv, %start
+  %t.2 = icmp ult ptr %ptr.iv, %upper
+  %and = and i1 %t.1, %t.2
+  br i1 %and, label %loop.latch, label %exit
+
+loop.latch:
+  call void @use(ptr %ptr.iv)
+  %ptr.iv.next = getelementptr i32, ptr %ptr.iv, i16 1
+  br label %loop.header
+
+exit:
+  ret void
+}
+
+define void @test_var_step_not_monotonic(ptr %start, i16 %len, i16 %step) {
+; CHECK-LABEL: @test_var_step_not_monotonic(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[UPPER:%.*]] = getelementptr inbounds i32, ptr [[START:%.*]], i16 [[LEN:%.*]]
+; CHECK-NEXT:    [[LEN_NEG:%.*]] = icmp slt i16 [[LEN]], 0
+; CHECK-NEXT:    br i1 [[LEN_NEG]], label [[EXIT:%.*]], label [[LOOP_PH:%.*]]
+; CHECK:       loop.ph:
+; CHECK-NEXT:    br label [[LOOP_HEADER:%.*]]
+; CHECK:       loop.header:
+; CHECK-NEXT:    [[PTR_IV:%.*]] = phi ptr [ [[START]], [[LOOP_PH]] ], [ [[PTR_IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
+; CHECK-NEXT:    [[C:%.*]] = icmp eq ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    br i1 [[C]], label [[EXIT]], label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[T_1:%.*]] = icmp uge ptr [[PTR_IV]], [[START]]
+; CHECK-NEXT:    [[T_2:%.*]] = icmp ult ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    [[AND:%.*]] = and i1 [[T_1]], [[T_2]]
+; CHECK-NEXT:    br i1 [[AND]], label [[LOOP_LATCH]], label [[EXIT]]
+; CHECK:       loop.latch:
+; CHECK-NEXT:    call void @use(ptr [[PTR_IV]])
+; CHECK-NEXT:    [[PTR_IV_NEXT]] = getelementptr inbounds i32, ptr [[PTR_IV]], i16 [[STEP:%.*]]
+; CHECK-NEXT:    br label [[LOOP_HEADER]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %upper = getelementptr inbounds i32, ptr %start, i16 %len
+  %len.neg = icmp slt i16 %len, 0
+  br i1 %len.neg, label %exit, label %loop.ph
+
+loop.ph:
+  br label %loop.header
+
+loop.header:
+  %ptr.iv = phi ptr [ %start, %loop.ph ], [ %ptr.iv.next, %loop.latch ]
+  %c = icmp eq ptr %ptr.iv, %upper
+  br i1 %c, label %exit, label %for.body
+
+for.body:
+  %t.1 = icmp uge ptr %ptr.iv, %start
+  %t.2 = icmp ult ptr %ptr.iv, %upper
+  %and = and i1 %t.1, %t.2
+  br i1 %and, label %loop.latch, label %exit
+
+loop.latch:
+  call void @use(ptr %ptr.iv)
+  %ptr.iv.next = getelementptr inbounds i32, ptr %ptr.iv, i16 %step
+  br label %loop.header
+
+exit:
+  ret void
+}
+
+define void @test_monotonic_ptr_iv_step_neg_1(ptr %start, i16 %len) {
+; CHECK-LABEL: @test_monotonic_ptr_iv_step_neg_1(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[UPPER:%.*]] = getelementptr inbounds i32, ptr [[START:%.*]], i16 [[LEN:%.*]]
+; CHECK-NEXT:    [[LEN_NEG:%.*]] = icmp slt i16 [[LEN]], 0
+; CHECK-NEXT:    br i1 [[LEN_NEG]], label [[EXIT:%.*]], label [[LOOP_PH:%.*]]
+; CHECK:       loop.ph:
+; CHECK-NEXT:    br label [[LOOP_HEADER:%.*]]
+; CHECK:       loop.header:
+; CHECK-NEXT:    [[PTR_IV:%.*]] = phi ptr [ [[START]], [[LOOP_PH]] ], [ [[PTR_IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
+; CHECK-NEXT:    [[C:%.*]] = icmp eq ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    br i1 [[C]], label [[EXIT]], label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[T_1:%.*]] = icmp uge ptr [[PTR_IV]], [[START]]
+; CHECK-NEXT:    [[T_2:%.*]] = icmp ult ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    [[AND:%.*]] = and i1 [[T_1]], [[T_2]]
+; CHECK-NEXT:    br i1 [[AND]], label [[LOOP_LATCH]], label [[EXIT]]
+; CHECK:       loop.latch:
+; CHECK-NEXT:    call void @use(ptr [[PTR_IV]])
+; CHECK-NEXT:    [[PTR_IV_NEXT]] = getelementptr inbounds i32, ptr [[PTR_IV]], i16 -1
+; CHECK-NEXT:    br label [[LOOP_HEADER]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %upper = getelementptr inbounds i32, ptr %start, i16 %len
+  %len.neg = icmp slt i16 %len, 0
+  br i1 %len.neg, label %exit, label %loop.ph
+
+loop.ph:
+  br label %loop.header
+
+loop.header:
+  %ptr.iv = phi ptr [ %start, %loop.ph ], [ %ptr.iv.next, %loop.latch ]
+  %c = icmp eq ptr %ptr.iv, %upper
+  br i1 %c, label %exit, label %for.body
+
+for.body:
+  %t.1 = icmp uge ptr %ptr.iv, %start
+  %t.2 = icmp ult ptr %ptr.iv, %upper
+  %and = and i1 %t.1, %t.2
+  br i1 %and, label %loop.latch, label %exit
+
+loop.latch:
+  call void @use(ptr %ptr.iv)
+  %ptr.iv.next = getelementptr inbounds i32, ptr %ptr.iv, i16 -1
+  br label %loop.header
+
+exit:
+  ret void
+}
+
+define void @test_monotonic_ptr_iv_step_sign_unknown(ptr %start, i16 %len, i16 %step) {
+; CHECK-LABEL: @test_monotonic_ptr_iv_step_sign_unknown(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[UPPER:%.*]] = getelementptr inbounds i32, ptr [[START:%.*]], i16 [[LEN:%.*]]
+; CHECK-NEXT:    [[LEN_NEG:%.*]] = icmp slt i16 [[LEN]], 0
+; CHECK-NEXT:    br i1 [[LEN_NEG]], label [[EXIT:%.*]], label [[LOOP_PH:%.*]]
+; CHECK:       loop.ph:
+; CHECK-NEXT:    br label [[LOOP_HEADER:%.*]]
+; CHECK:       loop.header:
+; CHECK-NEXT:    [[PTR_IV:%.*]] = phi ptr [ [[START]], [[LOOP_PH]] ], [ [[PTR_IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
+; CHECK-NEXT:    [[C:%.*]] = icmp eq ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    br i1 [[C]], label [[EXIT]], label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[T_1:%.*]] = icmp uge ptr [[PTR_IV]], [[START]]
+; CHECK-NEXT:    [[T_2:%.*]] = icmp ult ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    [[AND:%.*]] = and i1 [[T_1]], [[T_2]]
+; CHECK-NEXT:    br i1 [[AND]], label [[LOOP_LATCH]], label [[EXIT]]
+; CHECK:       loop.latch:
+; CHECK-NEXT:    call void @use(ptr [[PTR_IV]])
+; CHECK-NEXT:    [[PTR_IV_NEXT]] = getelementptr inbounds i32, ptr [[PTR_IV]], i16 [[STEP:%.*]]
+; CHECK-NEXT:    br label [[LOOP_HEADER]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %upper = getelementptr inbounds i32, ptr %start, i16 %len
+  %len.neg = icmp slt i16 %len, 0
+  br i1 %len.neg, label %exit, label %loop.ph
+
+loop.ph:
+  br label %loop.header
+
+loop.header:
+  %ptr.iv = phi ptr [ %start, %loop.ph ], [ %ptr.iv.next, %loop.latch ]
+  %c = icmp eq ptr %ptr.iv, %upper
+  br i1 %c, label %exit, label %for.body
+
+for.body:
+  %t.1 = icmp uge ptr %ptr.iv, %start
+  %t.2 = icmp ult ptr %ptr.iv, %upper
+  %and = and i1 %t.1, %t.2
+  br i1 %and, label %loop.latch, label %exit
+
+loop.latch:
+  call void @use(ptr %ptr.iv)
+  %ptr.iv.next = getelementptr inbounds i32, ptr %ptr.iv, i16 %step
+  br label %loop.header
+
+exit:
+  ret void
+}
+
+define void @test_monotonic_ptr_iv_step_sign_positive_through_assume(ptr %start, i16 %len, i16 %step) {
+; CHECK-LABEL: @test_monotonic_ptr_iv_step_sign_positive_through_assume(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[STEP_POS:%.*]] = icmp sge i16 [[STEP:%.*]], 0
+; CHECK-NEXT:    call void @llvm.assume(i1 [[STEP_POS]])
+; CHECK-NEXT:    [[UPPER:%.*]] = getelementptr inbounds i32, ptr [[START:%.*]], i16 [[LEN:%.*]]
+; CHECK-NEXT:    [[LEN_NEG:%.*]] = icmp slt i16 [[LEN]], 0
+; CHECK-NEXT:    br i1 [[LEN_NEG]], label [[EXIT:%.*]], label [[LOOP_PH:%.*]]
+; CHECK:       loop.ph:
+; CHECK-NEXT:    br label [[LOOP_HEADER:%.*]]
+; CHECK:       loop.header:
+; CHECK-NEXT:    [[PTR_IV:%.*]] = phi ptr [ [[START]], [[LOOP_PH]] ], [ [[PTR_IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
+; CHECK-NEXT:    [[C:%.*]] = icmp eq ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    br i1 [[C]], label [[EXIT]], label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[T_1:%.*]] = icmp uge ptr [[PTR_IV]], [[START]]
+; CHECK-NEXT:    [[T_2:%.*]] = icmp ult ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    [[AND:%.*]] = and i1 [[T_1]], [[T_2]]
+; CHECK-NEXT:    br i1 [[AND]], label [[LOOP_LATCH]], label [[EXIT]]
+; CHECK:       loop.latch:
+; CHECK-NEXT:    call void @use(ptr [[PTR_IV]])
+; CHECK-NEXT:    [[PTR_IV_NEXT]] = getelementptr inbounds i32, ptr [[PTR_IV]], i16 [[STEP]]
+; CHECK-NEXT:    br label [[LOOP_HEADER]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %step.pos = icmp sge i16 %step, 0
+  call void @llvm.assume(i1 %step.pos)
+  %upper = getelementptr inbounds i32, ptr %start, i16 %len
+  %len.neg = icmp slt i16 %len, 0
+  br i1 %len.neg, label %exit, label %loop.ph
+
+loop.ph:
+  br label %loop.header
+
+loop.header:
+  %ptr.iv = phi ptr [ %start, %loop.ph ], [ %ptr.iv.next, %loop.latch ]
+  %c = icmp eq ptr %ptr.iv, %upper
+  br i1 %c, label %exit, label %for.body
+
+for.body:
+  %t.1 = icmp uge ptr %ptr.iv, %start
+  %t.2 = icmp ult ptr %ptr.iv, %upper
+  %and = and i1 %t.1, %t.2
+  br i1 %and, label %loop.latch, label %exit
+
+loop.latch:
+  call void @use(ptr %ptr.iv)
+  %ptr.iv.next = getelementptr inbounds i32, ptr %ptr.iv, i16 %step
+  br label %loop.header
+
+exit:
+  ret void
+}
+
+define void @test_monotonic_ptr_iv_step_sign_negative_through_assume(ptr %start, i16 %len, i16 %step) {
+; CHECK-LABEL: @test_monotonic_ptr_iv_step_sign_negative_through_assume(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[STEP_POS:%.*]] = icmp sle i16 [[STEP:%.*]], 0
+; CHECK-NEXT:    call void @llvm.assume(i1 [[STEP_POS]])
+; CHECK-NEXT:    [[UPPER:%.*]] = getelementptr inbounds i32, ptr [[START:%.*]], i16 [[LEN:%.*]]
+; CHECK-NEXT:    [[LEN_NEG:%.*]] = icmp slt i16 [[LEN]], 0
+; CHECK-NEXT:    br i1 [[LEN_NEG]], label [[EXIT:%.*]], label [[LOOP_PH:%.*]]
+; CHECK:       loop.ph:
+; CHECK-NEXT:    br label [[LOOP_HEADER:%.*]]
+; CHECK:       loop.header:
+; CHECK-NEXT:    [[PTR_IV:%.*]] = phi ptr [ [[START]], [[LOOP_PH]] ], [ [[PTR_IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
+; CHECK-NEXT:    [[C:%.*]] = icmp eq ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    br i1 [[C]], label [[EXIT]], label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[T_1:%.*]] = icmp uge ptr [[PTR_IV]], [[START]]
+; CHECK-NEXT:    [[T_2:%.*]] = icmp ult ptr [[PTR_IV]], [[UPPER]]
+; CHECK-NEXT:    [[AND:%.*]] = and i1 [[T_1]], [[T_2]]
+; CHECK-NEXT:    br i1 [[AND]], label [[LOOP_LATCH]], label [[EXIT]]
+; CHECK:       loop.latch:
+; CHECK-NEXT:    call void @use(ptr [[PTR_IV]])
+; CHECK-NEXT:    [[PTR_IV_NEXT]] = getelementptr inbounds i32, ptr [[PTR_IV]], i16 [[STEP]]
+; CHECK-NEXT:    br label [[LOOP_HEADER]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %step.pos = icmp sle i16 %step, 0
+  call void @llvm.assume(i1 %step.pos)
+  %upper = getelementptr inbounds i32, ptr %start, i16 %len
+  %len.neg = icmp slt i16 %len, 0
+  br i1 %len.neg, label %exit, label %loop.ph
+
+loop.ph:
+  br label %loop.header
+
+loop.header:
+  %ptr.iv = phi ptr [ %start, %loop.ph ], [ %ptr.iv.next, %loop.latch ]
+  %c = icmp eq ptr %ptr.iv, %upper
+  br i1 %c, label %exit, label %for.body
+
+for.body:
+  %t.1 = icmp uge ptr %ptr.iv, %start
+  %t.2 = icmp ult ptr %ptr.iv, %upper
+  %and = and i1 %t.1, %t.2
+  br i1 %and, label %loop.latch, label %exit
+
+loop.latch:
+  call void @use(ptr %ptr.iv)
+  %ptr.iv.next = getelementptr inbounds i32, ptr %ptr.iv, i16 %step
+  br label %loop.header
+
+exit:
+  ret void
+}