[tests] Precommmit tests for reasoning about equality of recurrences

diff --git a/llvm/test/Analysis/ValueTracking/known-non-equal.ll b/llvm/test/Analysis/ValueTracking/known-non-equal.ll
index 0942045..e531149 100644 (file)
--- a/llvm/test/Analysis/ValueTracking/known-non-equal.ll
+++ b/llvm/test/Analysis/ValueTracking/known-non-equal.ll
@@ -485,4 +485,730 @@ define i1 @shl_shl_may_be_equal(i8 %A, i8 %B, i8 %shift) {
   ret i1 %cmp
 }
 
+define i1 @recurrence_add_neq(i8 %A) {
+; CHECK-LABEL: @recurrence_add_neq(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[B:%.*]] = add i8 [[A:%.*]], 1
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[A_IV:%.*]] = phi i8 [ [[A]], [[ENTRY]] ], [ [[A_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[B_IV:%.*]] = phi i8 [ [[B]], [[ENTRY]] ], [ [[B_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[A_IV_NEXT]] = add i8 [[A_IV]], 1
+; CHECK-NEXT:    [[B_IV_NEXT]] = add i8 [[B_IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A_IV]], [[B_IV]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  %B = add i8 %A, 1
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = add i8 %A.iv, 1
+  %B.iv.next = add i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_add_eq(i8 %A) {
+; CHECK-LABEL: @recurrence_add_eq(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[A_IV:%.*]] = phi i8 [ [[A:%.*]], [[ENTRY]] ], [ [[A_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[B_IV:%.*]] = phi i8 [ [[A]], [[ENTRY]] ], [ [[B_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[A_IV_NEXT]] = add i8 [[A_IV]], 1
+; CHECK-NEXT:    [[B_IV_NEXT]] = add i8 [[B_IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A_IV]], [[B_IV]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  %B = add i8 %A, 0
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = add i8 %A.iv, 1
+  %B.iv.next = add i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_add_unknown(i8 %A, i8 %B) {
+; CHECK-LABEL: @recurrence_add_unknown(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[A_IV:%.*]] = phi i8 [ [[A:%.*]], [[ENTRY]] ], [ [[A_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[B_IV:%.*]] = phi i8 [ [[B:%.*]], [[ENTRY]] ], [ [[B_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[A_IV_NEXT]] = add i8 [[A_IV]], 1
+; CHECK-NEXT:    [[B_IV_NEXT]] = add i8 [[B_IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A_IV]], [[B_IV]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = add i8 %A.iv, 1
+  %B.iv.next = add i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+
+define i1 @recurrence_sub_neq(i8 %A) {
+; CHECK-LABEL: @recurrence_sub_neq(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[B:%.*]] = sub i8 [[A:%.*]], 1
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[A_IV:%.*]] = phi i8 [ [[A]], [[ENTRY]] ], [ [[A_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[B_IV:%.*]] = phi i8 [ [[B]], [[ENTRY]] ], [ [[B_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[A_IV_NEXT]] = sub i8 [[A_IV]], 1
+; CHECK-NEXT:    [[B_IV_NEXT]] = sub i8 [[B_IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A_IV]], [[B_IV]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  %B = sub i8 %A, 1
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = sub i8 %A.iv, 1
+  %B.iv.next = sub i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_sub_eq(i8 %A) {
+; CHECK-LABEL: @recurrence_sub_eq(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[A_IV:%.*]] = phi i8 [ [[A:%.*]], [[ENTRY]] ], [ [[A_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[B_IV:%.*]] = phi i8 [ [[A]], [[ENTRY]] ], [ [[B_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[A_IV_NEXT]] = sub i8 [[A_IV]], 1
+; CHECK-NEXT:    [[B_IV_NEXT]] = sub i8 [[B_IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A_IV]], [[B_IV]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  %B = sub i8 %A, 0
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = sub i8 %A.iv, 1
+  %B.iv.next = sub i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_sub_unknown(i8 %A, i8 %B) {
+; CHECK-LABEL: @recurrence_sub_unknown(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[A_IV:%.*]] = phi i8 [ [[A:%.*]], [[ENTRY]] ], [ [[A_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[B_IV:%.*]] = phi i8 [ [[B:%.*]], [[ENTRY]] ], [ [[B_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[A_IV_NEXT]] = sub i8 [[A_IV]], 1
+; CHECK-NEXT:    [[B_IV_NEXT]] = sub i8 [[B_IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A_IV]], [[B_IV]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = sub i8 %A.iv, 1
+  %B.iv.next = sub i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_mul_neq(i8 %A) {
+; CHECK-LABEL: @recurrence_mul_neq(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret i1 false
+;
+entry:
+  %B = add i8 %A, 1
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = mul nuw i8 %A.iv, 1
+  %B.iv.next = mul nuw i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_mul_eq(i8 %A) {
+; CHECK-LABEL: @recurrence_mul_eq(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret i1 true
+;
+entry:
+  %B = add i8 %A, 0
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = mul nuw i8 %A.iv, 1
+  %B.iv.next = mul nuw i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_mul_unknown(i8 %A, i8 %B) {
+; CHECK-LABEL: @recurrence_mul_unknown(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A:%.*]], [[B:%.*]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = mul nuw i8 %A.iv, 1
+  %B.iv.next = mul nuw i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_mul_noflags(i8 %A, i8 %B) {
+; CHECK-LABEL: @recurrence_mul_noflags(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A:%.*]], [[B:%.*]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = mul i8 %A.iv, 1
+  %B.iv.next = mul i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_shl_neq(i8 %A) {
+; CHECK-LABEL: @recurrence_shl_neq(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[B:%.*]] = add i8 [[A:%.*]], 1
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[A_IV:%.*]] = phi i8 [ [[A]], [[ENTRY]] ], [ [[A_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[B_IV:%.*]] = phi i8 [ [[B]], [[ENTRY]] ], [ [[B_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[A_IV_NEXT]] = shl nuw i8 [[A_IV]], 1
+; CHECK-NEXT:    [[B_IV_NEXT]] = shl nuw i8 [[B_IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A_IV]], [[B_IV]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  %B = add i8 %A, 1
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = shl nuw i8 %A.iv, 1
+  %B.iv.next = shl nuw i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_shl_eq(i8 %A) {
+; CHECK-LABEL: @recurrence_shl_eq(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[A_IV:%.*]] = phi i8 [ [[A:%.*]], [[ENTRY]] ], [ [[A_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[B_IV:%.*]] = phi i8 [ [[A]], [[ENTRY]] ], [ [[B_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[A_IV_NEXT]] = shl nuw i8 [[A_IV]], 1
+; CHECK-NEXT:    [[B_IV_NEXT]] = shl nuw i8 [[B_IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A_IV]], [[B_IV]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  %B = add i8 %A, 0
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = shl nuw i8 %A.iv, 1
+  %B.iv.next = shl nuw i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_shl_unknown(i8 %A, i8 %B) {
+; CHECK-LABEL: @recurrence_shl_unknown(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[A_IV:%.*]] = phi i8 [ [[A:%.*]], [[ENTRY]] ], [ [[A_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[B_IV:%.*]] = phi i8 [ [[B:%.*]], [[ENTRY]] ], [ [[B_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[A_IV_NEXT]] = shl nuw i8 [[A_IV]], 1
+; CHECK-NEXT:    [[B_IV_NEXT]] = shl nuw i8 [[B_IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A_IV]], [[B_IV]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = shl nuw i8 %A.iv, 1
+  %B.iv.next = shl nuw i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_shl_noflags(i8 %A, i8 %B) {
+; CHECK-LABEL: @recurrence_shl_noflags(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[A_IV:%.*]] = phi i8 [ [[A:%.*]], [[ENTRY]] ], [ [[A_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[B_IV:%.*]] = phi i8 [ [[B:%.*]], [[ENTRY]] ], [ [[B_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[A_IV_NEXT]] = shl i8 [[A_IV]], 1
+; CHECK-NEXT:    [[B_IV_NEXT]] = shl i8 [[B_IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A_IV]], [[B_IV]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = shl i8 %A.iv, 1
+  %B.iv.next = shl i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_lshr_neq(i8 %A) {
+; CHECK-LABEL: @recurrence_lshr_neq(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[B:%.*]] = add i8 [[A:%.*]], 1
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[A_IV:%.*]] = phi i8 [ [[A]], [[ENTRY]] ], [ [[A_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[B_IV:%.*]] = phi i8 [ [[B]], [[ENTRY]] ], [ [[B_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[A_IV_NEXT]] = lshr exact i8 [[A_IV]], 1
+; CHECK-NEXT:    [[B_IV_NEXT]] = lshr exact i8 [[B_IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A_IV]], [[B_IV]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  %B = add i8 %A, 1
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = lshr exact i8 %A.iv, 1
+  %B.iv.next = lshr exact i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_lshr_eq(i8 %A) {
+; CHECK-LABEL: @recurrence_lshr_eq(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[A_IV:%.*]] = phi i8 [ [[A:%.*]], [[ENTRY]] ], [ [[A_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[B_IV:%.*]] = phi i8 [ [[A]], [[ENTRY]] ], [ [[B_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[A_IV_NEXT]] = lshr exact i8 [[A_IV]], 1
+; CHECK-NEXT:    [[B_IV_NEXT]] = lshr exact i8 [[B_IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A_IV]], [[B_IV]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  %B = add i8 %A, 0
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = lshr exact i8 %A.iv, 1
+  %B.iv.next = lshr exact i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_lshr_unknown(i8 %A, i8 %B) {
+; CHECK-LABEL: @recurrence_lshr_unknown(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[A_IV:%.*]] = phi i8 [ [[A:%.*]], [[ENTRY]] ], [ [[A_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[B_IV:%.*]] = phi i8 [ [[B:%.*]], [[ENTRY]] ], [ [[B_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[A_IV_NEXT]] = lshr exact i8 [[A_IV]], 1
+; CHECK-NEXT:    [[B_IV_NEXT]] = lshr exact i8 [[B_IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A_IV]], [[B_IV]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = lshr exact i8 %A.iv, 1
+  %B.iv.next = lshr exact i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_lshr_noflags(i8 %A, i8 %B) {
+; CHECK-LABEL: @recurrence_lshr_noflags(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[A_IV:%.*]] = phi i8 [ [[A:%.*]], [[ENTRY]] ], [ [[A_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[B_IV:%.*]] = phi i8 [ [[B:%.*]], [[ENTRY]] ], [ [[B_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[A_IV_NEXT]] = lshr i8 [[A_IV]], 1
+; CHECK-NEXT:    [[B_IV_NEXT]] = lshr i8 [[B_IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A_IV]], [[B_IV]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = lshr i8 %A.iv, 1
+  %B.iv.next = lshr i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_ashr_neq(i8 %A) {
+; CHECK-LABEL: @recurrence_ashr_neq(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[B:%.*]] = add i8 [[A:%.*]], 1
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[A_IV:%.*]] = phi i8 [ [[A]], [[ENTRY]] ], [ [[A_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[B_IV:%.*]] = phi i8 [ [[B]], [[ENTRY]] ], [ [[B_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[A_IV_NEXT]] = ashr exact i8 [[A_IV]], 1
+; CHECK-NEXT:    [[B_IV_NEXT]] = ashr exact i8 [[B_IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A_IV]], [[B_IV]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  %B = add i8 %A, 1
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = ashr exact i8 %A.iv, 1
+  %B.iv.next = ashr exact i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_ashr_eq(i8 %A) {
+; CHECK-LABEL: @recurrence_ashr_eq(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[A_IV:%.*]] = phi i8 [ [[A:%.*]], [[ENTRY]] ], [ [[A_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[B_IV:%.*]] = phi i8 [ [[A]], [[ENTRY]] ], [ [[B_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[A_IV_NEXT]] = ashr exact i8 [[A_IV]], 1
+; CHECK-NEXT:    [[B_IV_NEXT]] = ashr exact i8 [[B_IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A_IV]], [[B_IV]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  %B = add i8 %A, 0
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = ashr exact i8 %A.iv, 1
+  %B.iv.next = ashr exact i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_ashr_unknown(i8 %A, i8 %B) {
+; CHECK-LABEL: @recurrence_ashr_unknown(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[A_IV:%.*]] = phi i8 [ [[A:%.*]], [[ENTRY]] ], [ [[A_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[B_IV:%.*]] = phi i8 [ [[B:%.*]], [[ENTRY]] ], [ [[B_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[A_IV_NEXT]] = ashr exact i8 [[A_IV]], 1
+; CHECK-NEXT:    [[B_IV_NEXT]] = ashr exact i8 [[B_IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A_IV]], [[B_IV]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = ashr exact i8 %A.iv, 1
+  %B.iv.next = ashr exact i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
+define i1 @recurrence_ashr_noflags(i8 %A, i8 %B) {
+; CHECK-LABEL: @recurrence_ashr_noflags(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[A_IV:%.*]] = phi i8 [ [[A:%.*]], [[ENTRY]] ], [ [[A_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[B_IV:%.*]] = phi i8 [ [[B:%.*]], [[ENTRY]] ], [ [[B_IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[A_IV_NEXT]] = ashr i8 [[A_IV]], 1
+; CHECK-NEXT:    [[B_IV_NEXT]] = ashr i8 [[B_IV]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i64 [[IV_NEXT]], 10
+; CHECK-NEXT:    br i1 [[CMP]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i8 [[A_IV]], [[B_IV]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+entry:
+  br label %loop
+loop:
+  %iv = phi i64 [0, %entry], [%iv.next, %loop]
+  %A.iv = phi i8 [%A, %entry], [%A.iv.next, %loop]
+  %B.iv = phi i8 [%B, %entry], [%B.iv.next, %loop]
+  %iv.next = add i64 %iv, 1
+  %A.iv.next = ashr i8 %A.iv, 1
+  %B.iv.next = ashr i8 %B.iv, 1
+  %cmp = icmp ne i64 %iv.next, 10
+  br i1 %cmp, label %loop, label %exit
+exit:
+  %res = icmp eq i8 %A.iv, %B.iv
+  ret i1 %res
+}
+
 !0 = !{ i8 1, i8 5 }